Document:

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                                                                   EXHIBIT 10.13

                           PHASE FORWARD INCORPORATED

                            INDEMNIFICATION AGREEMENT

         This Indemnification Agreement ("AGREEMENT") is made as of
______________, 2004 by and between Phase Forward Incorporated, a Delaware
corporation (the "COMPANY"), and the undersigned ("INDEMNITEE").

         WHEREAS, the Company and Indemnitee recognize the increasing difficulty
in obtaining directors' and officers' liability insurance, the significant
increases in the cost of such insurance and the general reductions in the
coverage of such insurance;

         WHEREAS, the Company and Indemnitee further recognize the substantial
increase in corporate litigation in general, subjecting officers and directors
to expensive litigation risks at the same time as the availability and coverage
of liability insurance has been severely limited;

         WHEREAS, Indemnitee does not regard the current protection available as
adequate under the present circumstances, and Indemnitee and other officers and
directors of the Company may not be willing to continue to serve as officers and
directors without additional protection; and

         WHEREAS, the Company desires to attract and retain the services of
highly qualified individuals, such as Indemnitee, to serve as officers and
directors of the Company and to indemnify its officers and directors so as to
provide them with the maximum protection permitted by law.

         NOW, THEREFORE, the Company and Indemnitee hereby agree as follows:

         1.       INDEMNIFICATION.

                  (a)      Third Party Proceedings. The Company shall indemnify
Indemnitee if Indemnitee is or was a party or is threatened to be made a party
to any threatened, pending or completed action or proceeding, whether civil,
criminal, administrative or investigative (other than an action by or in the
right of the Company) by reason of the fact that Indemnitee is or was a
director, officer, employee or agent of the Company, or any subsidiary of the
Company, by reason of any action or inaction on the part of Indemnitee while an
officer or director or by reason of the fact that Indemnitee is or was serving
at the request of the Company as a director, officer, employee or agent of
another corporation, partnership, joint venture, trust or other enterprise,
against expenses (including attorneys' fees), judgments, fines and amounts paid
in settlement (if such settlement is approved in advance by the Company, which
approval shall not be unreasonably withheld) actually and reasonably incurred by
Indemnitee in connection with such action or proceeding if Indemnitee acted in
good faith and in a manner Indemnitee reasonably believed to be in or not
opposed to the best interests of the Company, and, with respect to any criminal
action or proceeding, had no reasonable cause to believe Indemnitee's conduct
was unlawful. The termination of any action or proceeding by judgment, order,
settlement, conviction, or upon a plea of nolo contendere or its equivalent,
shall not, of itself, create a presumption that (i) Indemnitee did not act in
good faith and in a manner which Indemnitee reasonably believed to be in or not
opposed to the best interests of the Company, or (ii) with respect to any
criminal action or proceeding, Indemnitee had reasonable cause to believe that
Indemnitee's conduct was unlawful.

                  (b)      Proceedings By or in the Right of the Company. The
Company shall indemnify Indemnitee if Indemnitee was or is a party or is
threatened to be made a party to any threatened, pending or completed action or
proceeding by or in the right of the Company or any subsidiary of the Company to
procure a judgment in its favor by reason of the fact that Indemnitee is or was
a director, officer, employee or agent of the Company, or any subsidiary of the
Company, by reason of any action or inaction on the part of Indemnitee while an
officer or director or by reason of the fact that Indemnitee is or was serving
at the request of the Company as a director, officer, employee or agent of
another corporation, partnership, joint venture, trust or other enterprise,
against expenses (including attorneys' fees) and, to the fullest extent
permitted by law, amounts paid in settlement, in each case to the extent
actually and reasonably incurred by Indemnitee in connection with the defense or
settlement of such action or proceeding if Indemnitee acted in good faith and in
a manner Indemnitee reasonably

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believed to be in or not opposed to the best interests of the Company and its
shareholders, except that no indemnification shall be made in respect of any
claim, issue or matter as to which Indemnitee shall have been finally
adjudicated by court orders or judgment to be liable to the Company in the
performance of Indemnitee's duty to the Company and its shareholders unless and
only to the extent that the court in which such action or proceeding is or was
pending shall determine upon application that, in view of all the circumstances
of the case, Indemnitee is fairly and reasonably entitled to indemnity for
expenses and then only to the extent that the court shall determine.

         2.       EXPENSES; INDEMNIFICATION PROCEDURE.

                  (a)      Advancement of Expenses. The Company shall advance
all expenses incurred by Indemnitee in connection with the investigation,
defense, settlement or appeal of any civil or criminal action or proceeding
referenced in Section 1(a) or (b) hereof (but not amounts actually paid in
settlement of any such action or proceeding). Indemnitee hereby undertakes to
repay such amounts advanced only if, and to the extent that, it shall ultimately
be determined that Indemnitee is not entitled to be indemnified by the Company
as authorized hereby. The advances to be made hereunder shall be paid by the
Company to Indemnitee within twenty (20) days following delivery of a written
request therefor by Indemnitee to the Company.

                  (b)      Notice/Cooperation by Indemnitee. Indemnitee shall,
as a condition precedent to his right to be indemnified under this Agreement,
give the Company notice in writing as soon as practicable of any claim made
against Indemnitee for which indemnification is or will be sought under this
Agreement. Notice to the Company shall be directed to the Chief Executive
Officer of the Company at the address shown on the signature page of this
Agreement (or such other address as the Company shall designate in writing to
Indemnitee). Notice shall be deemed received three (3) business days after the
date postmarked if sent by domestic certified or registered mail, properly
addressed; otherwise notice shall be deemed received when such notice shall
actually be received by the Company. In addition, Indemnitee shall give the
Company such information and cooperation as it may reasonably require and as
shall be within Indemnitee's power.

                  (c)      Procedure. Any indemnification and advances provided
for in Section 1 and this Section 2 shall be made no later than forty-five (45)
days after receipt of the written request of Indemnitee (or at such earlier time
as is provided in the applicable section). If a claim under this Agreement,
under any statute, or under any provision of the Company's Articles of
Incorporation or Bylaws providing for indemnification, is not paid in full by
the Company within the time allowed, Indemnitee may, but need not, at any time
thereafter bring an action against the Company to recover the unpaid amount of
the claim and, subject to Section 12 of this Agreement, Indemnitee shall also be
entitled to be paid for the expenses (including attorneys' fees) of bringing
such action. It shall be a defense to any such action (other than an action
brought to enforce a claim for expenses incurred in connection with any action
or proceeding in advance of its final disposition) that Indemnitee has not met
the standards of conduct which make it permissible under applicable law for the
Company to indemnify Indemnitee for the amount claimed, but the burden of
proving such defense shall be on the Company and Indemnitee shall be entitled to
receive interim payments of expenses pursuant to Subsection 2(a) unless and
until such defense may be finally adjudicated by court order or judgment from
which no further right of appeal exists. It is the parties' intention that if
the Company contests Indemnitee's right to indemnification, the question of
Indemnitee's right to indemnification shall be for the court to decide, and
neither the failure of the Company (including its Board of Directors, any
committee or subgroup of the Board of Directors, independent legal counsel, or
its shareholders) to have made a determination that indemnification of
Indemnitee is proper in the circumstances because Indemnitee has met the
applicable standard of conduct required by applicable law, nor an actual
determination by the Company (including its Board of Directors, any committee or
subgroup of the Board of Directors, independent legal counsel, or its
shareholders) that Indemnitee has not met such applicable standard of conduct,
shall create a presumption that Indemnitee has or has not met the applicable
standard of conduct.

                  (d)      Notice to Insurers. If, at the time of the receipt of
a notice of a claim pursuant to Section 3(b) hereof, the Company has director
and officer liability insurance in effect, the Company shall give prompt notice
of the commencement of such proceeding to the insurers in accordance with the
procedures set forth in the respective policies. The Company shall thereafter
take all necessary or desirable action to cause such

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insurers to pay, on behalf of the Indemnitee, all amounts payable as a result of
such proceeding in accordance with the terms of such policies.

                  (e)      Selection of Counsel. In the event the Company shall
be obligated under Section 2(a) hereof to pay the expenses of any proceeding
against Indemnitee, the Company, if appropriate, shall be entitled to assume the
defense of such proceeding, with counsel approved by Indemnitee, which approval
shall not be unreasonably withheld, upon the delivery to Indemnitee of written
notice of its election so to do. Notwithstanding the foregoing, the Company
shall not be permitted to settle any action or claim on behalf of Indemnitee in
any manner which would require any acknowledgment of wrongdoing on the part of
Indemnitee without Indemnitee's written consent, which consent shall not be
unreasonably withheld. After delivery of such notice, approval of such counsel
by Indemnitee and the retention of such counsel by the Company, the Company will
not be liable to Indemnitee under this Agreement for any fees of counsel
subsequently incurred by Indemnitee with respect to the same proceeding,
provided that (i) Indemnitee shall have the right to employ his counsel in any
such proceeding at Indemnitee's expense; and (ii) if (A) the employment of
counsel by Indemnitee has been previously authorized by the Company, (B)
Indemnitee shall have reasonably concluded that there may be a conflict of
interest between the Company and Indemnitee in the conduct of any such defense,
or (C) the Company shall not, in fact, have employed counsel to assume the
defense of such proceeding, then the fees and expenses of Indemnitee's counsel
shall be at the expense of the Company.

         3.       ADDITIONAL INDEMNIFICATION RIGHTS; NONEXCLUSIVITY.

                  (a)      Scope. Notwithstanding any other provision of this
Agreement, the Company hereby agrees to indemnify the Indemnitee to the fullest
extent permitted by law, notwithstanding that such indemnification is not
specifically authorized by the other provisions of this Agreement, the Company's
Articles of Incorporation, the Company's Bylaws or by statute. In the event of
any change, after the date of this Agreement, in any applicable law, statute or
rule which expands the right of a Delaware corporation to indemnify a member of
its Board of Directors, an officer or other corporate agent, such changes shall
be ipso facto, within the preview of Indemnitee's rights and Company's
obligations, under this Agreement. In the event of any change in any applicable
law, statute or rule which narrows the right of a Delaware corporation to
indemnify a member of its Board of Directors, an officer or other corporate
agent, such changes, to the extent not otherwise required by such law, statute
or rule to be applied to this Agreement shall have no effect on this Agreement
or the parties' rights and obligations hereunder.

                  (b)      Nonexclusivity. The indemnification provided by this
Agreement shall not be deemed exclusive of any rights to which Indemnitee may be
entitled under the Company's Articles of Incorporation, its Bylaws, any
agreement, any vote of shareholders or disinterested Directors, the General
Corporation Law of the State of Delaware (the "DGCL"), or otherwise, both as to
action in Indemnitee's official capacity and as to action in another capacity
while holding such office. The indemnification provided under this Agreement
shall continue as to Indemnitee for any action taken or not taken while serving
in an indemnified capacity even though he may have ceased to serve in such
capacity at the time of any action, suit or other covered proceeding.

         4.       PARTIAL INDEMNIFICATION. If Indemnitee is entitled under any
provision of this Agreement to indemnification by the Company for some or a
portion of the expenses, judgments, fines or penalties actually or reasonably
incurred by him in the investigation, defense, appeal or settlement of any civil
or criminal action or proceeding, but not, however, for the total amount
thereof, the Company shall nevertheless indemnify Indemnitee for the portion of
such expenses, judgments, fines or penalties to which Indemnitee is entitled.

         5.       MUTUAL ACKNOWLEDGMENT. Both the Company and Indemnitee
acknowledge that in certain instances, Federal law or applicable public policy
may prohibit the Company from indemnifying its directors and officers under this
Agreement or otherwise. Indemnitee understands and acknowledges that the Company
has undertaken or may be required in the future to undertake with the Securities
and Exchange Commission to submit the question of indemnification to a court in
certain circumstances for a determination of the Company's right under public
policy to indemnify Indemnitee.

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         6.       OFFICER AND DIRECTOR LIABILITY INSURANCE. The Company shall,
from time to time, make the good faith determination whether or not it is
desirable for the Company to obtain and maintain a policy or policies of
insurance with reputable insurance companies providing the officers and
directors of the Company with coverage for losses from wrongful acts, or to
ensure the Company's performance of its indemnification obligations under this
Agreement. Among other considerations, the Company will weigh the costs of
obtaining such insurance coverage against the protection afforded by such
coverage. In all policies of director and officer liability insurance,
Indemnitee shall be named as an insured in such a manner as to provide
Indemnitee the same rights and benefits as are accorded to the most favorably
insured of the Company's directors, if Indemnitee is a director; or of the
Company's officers, if Indemnitee is not a director of the Company but is an
officer; or of the Company's key employees, if Indemnitee is not an officer or
director but is a key employee. Notwithstanding the foregoing, the Company shall
have no obligation to obtain or maintain such insurance if the Company
determines in good faith that such insurance is not reasonably available, if the
premium costs for such insurance are disproportionate to the amount of coverage
provided, if the coverage provided by such insurance is limited by exclusions so
as to provide an insufficient benefit, or if Indemnitee is covered by similar
insurance maintained by a subsidiary or parent of the Company.

         7.       SEVERABILITY. Nothing in this Agreement is intended to require
or shall be construed as requiring the Company to do or fail to do any act in
violation of applicable law. The Company's inability, pursuant to court order,
to perform its obligations under this Agreement shall not constitute a breach of
this Agreement. The provisions of this Agreement shall be severable as provided
in this Section 7. If this Agreement or any portion hereof shall be invalidated
on any ground by any court of competent jurisdiction, then the Company shall
nevertheless indemnify Indemnitee to the full extent permitted by any applicable
portion of this Agreement that shall not have been invalidated, and the balance
of this Agreement not so invalidated shall be enforceable in accordance with its
terms.

         8.       EXCEPTIONS. Any other provision herein to the contrary
notwithstanding, the Company shall not be obligated pursuant to the terms of
this Agreement:

                  (a)      Excluded Acts. To indemnify Indemnitee for any acts
or omissions or transactions from which a director may not be relieved of
liability under the DGCL.

                  (b)      Claims Initiated by Indemnitee. To indemnify or
advance expenses to Indemnitee with respect to proceedings or claims initiated
or brought voluntarily by Indemnitee and not by way of defense, except with
respect to proceedings brought to establish or enforce a right to
indemnification under this Agreement or any other statute or law or otherwise as
required under the DGCL, but such indemnification or advancement of expenses may
be provided by the Company in specific cases if the Board of Directors has
approved the initiation or bringing of such suit.

                  (c)      Lack of Good Faith. To indemnify Indemnitee for any
expenses incurred by the Indemnitee with respect to any proceeding instituted by
Indemnitee to enforce or interpret this Agreement, if a court of competent
jurisdiction determines that each of the material assertions made by the
Indemnitee in such proceeding was not made in good faith or was frivolous.

                  (d)      Insured Claims. To indemnify Indemnitee for expenses
or liabilities of any type whatsoever (including, but not limited to, judgments,
fines, ERISA excise taxes or penalties, and amounts paid in settlement), but
such exception shall only apply to the extent such expenses or liabilities have
been paid directly to Indemnitee by an insurance carrier, provided that such
limitation shall not apply to any expenses incurred by Indemnitee which except
for this paragraph would be paid hereunder and which remain outstanding after
all payments are received from an insurance company.

                  (e)      Claims Under Section 16(b). To indemnify Indemnitee
for expenses and the payment of profits arising from the purchase and sale by
Indemnitee of securities in violation of Section 16(b) of the Securities
Exchange Act of 1934, as amended, or any similar successor statute.

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         9.       CONSTRUCTION OF CERTAIN PHRASES.

                  (a)      For purposes of this Agreement, references to the
"Company" shall include, in addition to the resulting corporation, any
constituent corporation (including any constituent of a constituent) absorbed in
a consolidation or merger which, if its separate existence had continued, would
have had power and authority to indemnify its directors, officers, and employees
or agents, so that if Indemnitee is or was a director, officer, employee or
agent of such constituent corporation, or is or was serving at the request of
such constituent corporation as a director, officer, employee or agent of
another corporation, partnership, joint venture, trust or other enterprise,
Indemnitee shall stand in the same position under the provisions of this
Agreement with respect to the resulting or surviving corporation as Indemnitee
would have with respect to such constituent corporation if its separate
existence had continued.

                  (b)      For purposes of this Agreement, references to "other
enterprises" shall include employee benefit plans; references to "fines" shall
include any excise taxes assessed on Indemnitee with respect to an employee
benefit plan; and references to "serving at the request of the Company" shall
include any service as a director, officer, employee or agent of the Company
which imposes duties on, or involves services by, such director, officer,
employee or agent with respect to an employee benefit plan, its participants, or
beneficiaries; and if Indemnitee acted in good faith and in a manner Indemnitee
reasonably believed to be in the interest of the participants and beneficiaries
of an employee benefit plan, Indemnitee shall be deemed to have acted in a
manner "not opposed to the best interests of the Company" as referred to in this
Agreement.

         10.      COUNTERPARTS. This Agreement may be executed in counterparts,
each of which shall constitute an original.

         11.      SUCCESSORS AND ASSIGNS. This Agreement shall be binding upon
the Company and its successors and assigns, and shall inure to the benefit of
Indemnitee and Indemnitee's estate, heirs, legal representatives and assigns.

         12.      ATTORNEYS' FEES. In the event that any action is instituted by
Indemnitee under this Agreement to enforce or interpret any of the terms hereof,
Indemnitee shall be entitled to be paid all costs and expenses, including
reasonable attorneys' fees, incurred by Indemnitee with respect to such action,
unless as a part of such action, the court of competent jurisdiction determines
that each of the material assertions made by Indemnitee as a basis for such
action were not made in good faith or were frivolous. In the event of an action
instituted by or in the name of the Company under this Agreement or to enforce
or interpret any of the terms of this Agreement, Indemnitee shall be entitled to
be paid all costs and expenses, including reasonable attorneys' fees, incurred
by Indemnitee in defense of such action (including with respect to Indemnitee's
counterclaims and cross-claims made in such action), unless as a part of such
action the court determines that each of Indemnitee's material defenses to such
action were made in bad faith or were frivolous.

         13.      NOTICE. All notices, requests, demands and other
communications under this Agreement shall be in writing and shall be deemed duly
given (i) if delivered by hand and receipted for by the party addressee, on the
date of such receipt, or (ii) if mailed by domestic certified or registered mail
with postage prepaid, on the third business day after the date postmarked.
Addresses for notice to either party are as shown on the signature page of this
Agreement, or as subsequently modified by written notice.

         14.      CONSENT TO JURISDICTION. The Company and Indemnitee each
hereby irrevocably consent to the jurisdiction of the courts of the State of
Delaware for all purposes in connection with any action or proceeding which
arises out of or relates to this Agreement and agree that any action instituted
under this Agreement shall be brought only in the state courts of the State of
Delaware.

         15.      CHOICE OF LAW. This Agreement shall be governed by and its
provisions construed in accordance with the laws of the State of Delaware,
without regard to principles of conflict of laws.

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         16.      SUBROGATION. In the event of payment under this Agreement, the
Company shall be subrogated to the extent of such payment to all of the rights
of recovery of Indemnitee, who shall execute all documents required and shall do
all acts that may be necessary to secure such rights and to enable to
corporation effectively to bring suit to enforce such rights.

         17.      CONTINUATION OF INDEMNIFICATION. All agreements and
obligations of the Company contained herein shall continue during the period
that Indemnitee is a director, officer or agent of the Company and shall
continue thereafter so long as Indemnitee shall be subject to any possible claim
or threatened, pending or completed action, suit or proceeding, whether civil,
criminal, arbitrational, administrative or investigative, by reason of the fact
that Indemnitee was serving in the capacity referred to herein.

         18.      AMENDMENT AND TERMINATION. Subject to Section 17, no
amendment, modification, termination or cancellation of this Agreement shall be
effective unless in writing signed by both parties hereto.

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the date first above written.

                                              PHASE FORWARD INCORPORATED

                                              By:_______________________________

                                                 Name:
                                                 Title:
                                                 Phase Forward Incorporated
                                                 880 Winter Street
                                                 Waltham, MA  02451

AGREED TO AND ACCEPTED:

INDEMNITEE:

____________________________
Signature

____________________________
Name

____________________________
Street Address

____________________________
City, State, Zip

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                                                                   EXHIBIT 10.14

                               SUBLEASE AGREEMENT

         THIS SUBLEASE AGREEMENT (the "Sublease") dated as of November 3, 2003
is entered into by and between BMC SOFTWARE, INC., a Delaware corporation,
successor by merger to BGS Systems, Inc., a Massachusetts corporation
("Sublessor"), and PHASE FORWARD INCORPORATED, a Delaware corporation
("Sublessee").

                                    RECITALS:

         A.       Sublessor and 880 Winter Street, LLC ("Landlord") entered into
that certain Lease dated as of July 15, 1998 (as from time to time amended, the
"Base Lease") wherein Landlord leased to Sublessor and Sublessor leased from
Landlord certain premises (the "Leased Premises") in the office building located
at 880 Winter Street, Waltham, Massachusetts (the "Building") located in a
multiple building office park known as Waltham Woods Corporate Center (the
"Complex").

         B.       Sublessee desires to sublease from Sublessor and Sublessor
desires to sublease to Sublessee the Subleased Premises (as hereinafter defined)
subject to the terms and conditions hereof.

                                   AGREEMENTS:

         NOW, THEREFORE, in consideration of the mutual promises and covenants
herein contained, and for other good and valuable consideration paid by each
party hereto to the other, Sublessor and Sublessee agree as follows:

         1.       Terms. Capitalized terms used herein but not defined herein
shall have the meanings specified in the Base Lease.

         2.       Sublease Grant.

                  (a)      Agreement to Sublease. Sublessor subleases to
Sublessee, and Sublessee subleases from Sublessor, a portion of the Leased
Premises located on the first (1st) and second (2nd) floors of the Building (the
"Subleased Premises") in accordance with and subject to the Base Lease and the
terms, conditions and provisions of this Sublease. Sublessor and Sublessee agree
that the Subleased Premises consist of approximately 98,968 rentable square feet
of space. A floor plan depicting the Subleased Premises is attached hereto as
Exhibit A.

                  (b)      Appurtenant Rights. Sublessee shall have, as
appurtenant to the Subleased Premises, the non-exclusive right to use all
parking areas, driveways, sidewalks and other common facilities to the extent
permitted under the Base Lease, but such rights shall always be subject to the
terms and conditions of the Base Lease, the rules and regulations from time to
time established by Landlord, and the right of Landlord to designate and change
from time to time the areas and facilities to be so used.

                                      -1-
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         3.       Term. This Sublease shall be binding on the parties hereto as
of the date hereof, even though the term (the "Sublease Term") of this Sublease
shall commence on the later of (a) December 15, 2003 and (b) the date as of
which both (i) this Sublease Agreement has been fully executed by Sublessor and
Sublessee and (ii) Landlord has given its written consent to this Sublease
Agreement (such later date is referred to herein as the "Commencement Date"),
and shall expire on February 28, 2009, unless earlier terminated pursuant to the
terms of this Sublease. Delivery of the Subleased Premises to Sublessee shall
occur on the Commencement Date. If the Commencement Date does not occur by
December 15, 2003, Sublessee shall have the right, by written notice to
Sublessor delivered by December 31, 2003 to terminate this Sublease, in which
event the Security Deposit shall be returned by Sublessor to Sublessee, any
amount of the Tenant Allowance funded by Sublessor shall be returned by
Sublessee to Sublessor (and if the Tenant Allowance is not returned along with
the notice of termination, Sublessor may draw under the Security Deposit), and
neither party shall have any additional obligations hereunder.

         4.       Rent.

                  (a)      Sublessee agrees to pay to Sublessor, or as directed
by Sublessor, commencing on the Commencement Date, without offset, abatement
(except as provided herein), deduction or demand, as rent (the "Base Rental")
for the Subleased Premises, the following amounts for the following periods of
time:

<TABLE>
<CAPTION>
                                         ANNUAL BASE RENTAL RATE
                                         PER RENTABLE SQUARE FOOT
                                     (NET OF ELECTRICITY FOR LIGHTS       MONTHLY
           TIME PERIOD                   AND  CONVENIENCE PLUGS)        BASE RENTAL
---------------------------------    -------------------------------    -----------
<S>                                  <C>                                <C>
Commencement Date- March 31, 2006              $17.50                   $144,328.33
April 1, 2006 - March 31, 2007                 $18.75                   $154,637.50
April 1, 2007 - March 31, 2008                 $19.75                   $162,884.83
April 1, 2008 - February 28, 2009              $21.00                   $173,194.00
</TABLE>

Such Base Rental shall be payable monthly, in advance, on the first day of each
and every calendar month during the Sublease Term, at 2101 CityWest Blvd.,
Houston, Texas 77042, Attn: Manager of Corporate Real Estate, or at such other
place as Sublessor shall from time to time designate by notice, in lawful money
of the United States. Sublessor and Sublessee agree that all amounts due from
Sublessee under or in respect of this Sublease, whether labeled Base Rental,
Additional Charges or otherwise, shall be considered as rental reserved under
this Sublease for all purposes, including without limitation, regulations
promulgated pursuant to the Bankruptcy Code, including further without
limitation, Section 502(b) thereof.

                                      -2-
<PAGE>

Notwithstanding anything to the contrary in this Sublease, Base Rental shall be
accrued for the period commencing on the Commencement Date and ending March 31,
2005 (the "Accrued Base Rental"), but shall conditionally not be due and owing
by Sublessee as provided below. Commencing April 1, 2005, Sublessee shall (i)
make Base Rental payments as otherwise provided in this Sublease and (ii) the
Accrued Base Rental shall be permanently abated in installments of $144,328.33
per month for the period from April 1, 2005 through June 30, 2006, with the
final installment of $72,164.17 being permanently abated on July 15, 2006. The
portion of the Accrued Base Rental not yet abated is the "Unabated Amount."
Notwithstanding the deferral of the obligation to pay the Accrued Base Rental,
if at any time during the Sublease Term prior to the full permanent abatement
thereof, a Major Default by Sublessee occurs hereunder, then the Unabated Amount
shall be due and owing as of the date originally payable and Sublessee shall
promptly pay to Sublessor in addition to all other amounts due to Sublessor
under this Lease, the full amount of the Unabated Amount. A "Major Default"
shall be any Default in the payment of an amount due under this Sublease or a
material non-monetary Default under this Sublease.

                  (b)      Base Rental for any partial month of the Term shall
be prorated on a daily basis.

         5.       Additional Charges.

                  (a)      Sublessee shall pay to Sublessor, as Additional
Charges (herein so called), an amount equal to Sublessee's Proportionate Share
(defined below) of the charges for Taxes and for Operating Expenses (as such
terms are defined in the Base Lease) that are payable by Sublessor pursuant to
Sections 8 and 9 of the Base Lease; provided, however, that for purposes of
calculating Sublessee's Proportionate Share of such Additional Charges, the
calendar year 2005 will serve as a base year, and Sublessee will only be
obligated to pay such charges for Taxes and for Operating Expenses to the extent
that such charges for Taxes and for Operating Expenses exceed the charges for
Taxes and for Operating Expenses payable by Sublessor for the calendar year 2005
under the Base Lease. Such Additional Charges shall be apportioned for any
portion of a lease year in which the Sublease Term ends. As used herein,
"Sublessee's Proportionate Share" shall mean 56.37%, which is the percentage
obtained by dividing the number of rentable square feet of space in the
Subleased Premises (98,968) by the number of rentable square feet of space in
the Leased Premises (175,584). All such payments of Additional Charges shall be
made by Sublessee to Sublessor at the address provided herein for payment of
Base Rental, in the manner and at the times upon which payments of Additional
Charges are due and payable by Sublessor to Landlord under Sections 8 and 9 of
the Base Lease (including estimated monthly payments).

                  (b)      Sublessee acknowledges that the Base Rental does not
include the cost of providing convenience electricity to the Premises. In
addition to Base Rental and the other amounts payable by Sublessee pursuant to
this Section 5, Sublessee shall pay to Sublessor, as part of Additional Charges
payable by Sublessee to Sublessor under this Sublease, the cost of such
electricity for the Subleased Premises in accordance with the terms and
provisions set out in Section 7.5 of the Base Lease. Sublessee further
acknowledges that pursuant to Section 7.5 of the Base Lease Sublessee's use of
electric energy in the Subleased Premises shall not at any time exceed the
electrical capacity set forth in Section 7.5. Furthermore, Sublessee shall not
make

                                      -3-
<PAGE>

any alteration or addition to the electric system of the Subleased Premises
existing from time to time without Sublessor's and Landlord's prior written
consent in each instance. Nothing in this Section 5(b) shall be deemed to change
any of the provisions of Section 7.5 of the Base Lease or Section 11 of this
Sublease or to impose any obligations on Sublessor to provide any electrical
service.

                  (c)      Sublessor, at Sublessor's option, may make a good
faith estimate of the Additional Charges to be due by Sublessee under Sections
5(a) and (b) for any calendar year (or part thereof) during the Sublease Term
that such amounts are due (i.e., commencing on the Commencement Date, as to the
cost of any electrical service, and beginning on January 1, 2006 as to charges
for Taxes and Operating Expenses), and Sublessee shall pay to Sublessor, on the
first day of each calendar month of such calendar year or applicable portion
thereof, an amount equal to such estimated Additional Charges for such calendar
year or part thereof divided by the number of months therein. From time to time,
Sublessor may estimate and re-estimate the Additional Charges to be due to
Sublessor under Sections 5(a) and (b) and deliver a copy of the estimate or
re-estimate to Sublessee. Thereafter, monthly installments of Additional Charges
payable by Sublessor under Sections 5(a) and (b) shall be appropriately adjusted
in accordance with the estimations so that, by the end of the calendar year in
question, Sublessee shall have paid all of such Additional Charges as estimated
by Sublessor.

                  (d)      After the end of each calendar year during the
Sublease Term, Sublessor will forward to Sublessee any documents submitted to
Sublessor by Landlord for the purpose of showing the actual Operating Expenses
for such lease year. If Sublessee has paid more in estimated Additional Charges
than the actual amount payable under Sections 5(a) and (b) for the year for
which such statement was prepared, the Sublessor shall credit such excess
against subsequent obligations of Sublessee with respect to Base Rental and
Additional Charges (or refund within 30 days if the Term has ended and Sublessee
has no further obligation to Sublessor); likewise, if Sublessee paid less in
estimated Additional Charges than the actual amount payable under Sections 5(a)
and (b), then Sublessee shall promptly pay to Sublessor such deficiency.

                  (e)      In the event Sublessor shall be obligated under the
Base Lease to pay to Landlord any amounts for any additional services provided
by Landlord to Sublessee or the Subleased Premises (for example, additional
air-conditioning service), Sublessee shall pay to Sublessor, upon the receipt by
Sublessee of an invoice for such additional services, as Additional Charges, the
amounts required with respect thereto. In addition, to the extent that any
utilities provided to the Subleased Premises are not separately metered,
Sublessee shall pay to Sublessor, as Additional Charges, the cost of all such
utilities provided to the Subleased Premises as allocated to the Subleased
Premises by Sublessor on a reasonable basis. All payments of Additional Charges
payable by Sublessee under this Section 5(e) shall be made by Sublessee to
Sublessor at the address provided herein for payment of Base Rental, in the
manner and at the times upon which payments of the amounts for such services are
due and payable by Sublessor to Landlord under the Base Lease.

         6.       Condition. SUBLESSEE AGREES THAT IT HAS INSPECTED THE
SUBLEASED PREMISES AND THAT THE SUBLEASED PREMISES ARE SUITABLE FOR ITS PURPOSE.
SUBLESSEE ACCEPTS THE SUBLEASED PREMISES IN ITS

                                      -4-
<PAGE>

"AS IS" CONDITION AND ACKNOWLEDGES THAT NO REPRESENTATION OR WARRANTY, EITHER
EXPRESS OR IMPLIED, WRITTEN OR ORAL, HAS BEEN MADE BY SUBLESSOR WITH RESPECT TO
THE CONDITION OF THE SUBLEASED PREMISES OR ITS SUITABILITY FOR ANY USE OR
PURPOSE BY SUBLESSEE. THE PROVISIONS OF THIS SECTION ARE A MATERIAL PART OF THE
CONSIDERATION FOR SUBLESSOR ENTERING INTO THIS SUBLEASE. NOTWITHSTANDING THE
FOREGOING, SUBLESSOR AGREES TO DELIVER THE SUBLEASED PREMISES IN BROOM-CLEAN
CONDITION, FREE OF ALL TENANTS AND OCCUPANTS AND FREE OF ALL PERSONAL PROPERTY,
OTHER THAN THE PERSONAL PROPERTY LISTED IN EXHIBIT C HEREOF.

         7.       Improvements to the Subleased Premises.

                  (a)      Sublessee acknowledges and agrees that Sublessor has
no obligation with regard to any improvements made or required to be made by
Landlord to the Subleased Premises. Sublessee shall not make any improvements,
alterations or additions to the Subleased Premises without the prior written
consent of and approval of the plans and specifications therefor by (i)
Sublessor and (ii) if required under the Base Lease, Landlord.

                  (b)      Sublessor shall provide Sublessee with an allowance
of $494,840.00 (the "Tenant Improvement Allowance") equal to $5.00 per rentable
square foot contained in the Subleased Premises to be paid as follows:

                           (i)      $247,420.00 paid to Sublessee as of the
         execution of this Sublease by all parties hereto; and

                           (ii)     the remainder ($247,420.00) paid against
         presentation to Sublandlord of paid invoices and related lien releases
         (in form reasonably acceptable to Sublessor), reflecting payments made
         in excess of the amount described in (i) above to contractors,
         suppliers and consultants of Sublessee for the costs incurred by
         Sublessee to construct improvements in the Subleased Premises
         (including space planning/interior architect, engineering and other
         similar consultants' fees, costs of cabling, costs of relocation, costs
         of installation of information technology, and costs of furniture and
         fixtures for the Subleased Premises) in accordance with the terms and
         conditions of this Sublease and the Base Lease. Sublessor shall
         promptly provide (and Sublessor shall have no obligation to fund any
         part of the amount described in this subsection (ii) until) paid
         invoices and related liens releases of the type and for the purpose
         described in this subsection (ii) have been received by Sublessor for
         the amount funded to Sublessee under (i) above. To the extent that any
         of the Tenant Improvement Allowance is not required to be funded by
         Sublessor as provided for in this Section 7(b) by June 30, 2004,
         Sublessor shall credit any such unused amount against the
         installment(s) of Base Rental next coming due hereunder.

         8.       Performance Obligations. Sublessee hereby agrees, for the
benefit of Sublessor and Landlord, to comply with all of the provisions of the
Base Lease with respect to the Subleased premises that are to be observed or
performed during the Sublease Term by Sublessor

                                      -5-
<PAGE>

as "Tenant" thereunder, including the rules and regulations applicable to the
Building, except as otherwise inconsistent with the agreements and
understandings expressly provided herein.

         9.       Assignment and Subletting.

         (a)      Sublessee shall not assign this Sublease or sublease the
Subleased Premises or any part thereof without first obtaining the prior written
consent of Sublessor, which consent shall not be unreasonably withheld, delayed
or conditioned. In no event shall Sublessor be obligated to consent to an
assignment or sublease of the Subleased Premises to any of the following
entities: Compuware, NEON Systems, Inc., Computer Associates International,
Inc., Envive Corporation, Micromuse, Inc., Net IQ, HP Openview, Tivoli Systems,
Inc., or any entity controlling, controlled by or under common control with any
of the foregoing or any other entity in direct competition with Sublessor.

         (b)      Any assignment or sublease shall be in accordance with and
subject to the terms of the Base Lease, including, without limitation,
Landlord's right of consent and approval of any assignment or sublease.
Notwithstanding any assignment or sublease by Sublessee, Sublessee shall remain
primarily liable and shall continue to make all rental payments and all other
payments that may become due and payable hereunder to Sublessor in a timely
manner. Sublessee shall pay to Sublessor, immediately upon receipt thereof,
fifty percent (50%) of the excess of (1) all compensation received by Sublessee
for an assignment or subletting by Sublessee less the costs reasonably incurred
by Sublessee with unaffiliated third parties in connection therewith (i.e.,
brokerage commissions, tenant finish work, rent concessions, moving expenses and
attorneys' fees) over (2) the Base Rental allocable to the portion of the
Subleased Premises covered thereby. The right of Sublessee to receive fifty
percent (50%) of such excess shall apply only until such time as under the Base
Lease Sublessor is obligated to make payments to Landlord under the terms of the
Base Lease, and as to any amounts received thereafter Sublessee shall have no
rights to share in such excess. Any assignment or subletting by Sublessee in
violation of this Section 9 shall constitute an event of Default under this
Sublease, entitling Sublessor to exercise any and all of the remedies herein
provided for an event of Default by Sublessee, including, but not limited to,
termination of this Sublease. Sublessor may assign this Sublease in accordance
with the provisions of the Base Lease. Sublessee shall reimburse Sublessor upon
request for its reasonably attorneys' fees incurred in connection with
considering (and documentation of) any request for consent to an assignment or
subletting.

         (c)      In order to comply with the terms of Section 6.5(d) of the
Base Lease: (i) this Sublease shall not be valid, and Sublessee shall not take
possession of all or any part of the Subleased Premises until a fully executed
counterpart of this Sublease has been delivered to Landlord; (ii) this Sublease
is subject and subordinate to this Lease; (iii) Landlord may enforce the
provisions of this Sublease, including collection of rents; and (iv) in the
event of termination of the Base Lease or reentry or repossession of the
Premises by Landlord, Landlord may, at its option, take over all of the right,
title and interest of Sublessor, under the Sublease, and Sublessee shall, at
Landlord's option, attorn to Landlord but nevertheless Landlord shall not (A) be
liable for any previous act or omission of Sublessor under the Sublease; (B) be
subject to any defense or offset previously accrued in favor of Sublessee
against Sublessor; or (C) be bound by

                                      -6-
<PAGE>

any previous modification of such sublease made without Landlord's written
consent or by any previous prepayment of more than one month's rent.

         10.      Default. In the event of a default by Sublessee in the full
and timely performance of its obligations under (or compliance with the terms
of) this Sublease, including, without limitation, its obligations to pay Base
Rental or Additional Charges and to comply with and perform the provisions
incorporated herein under Article 14, then in the case of a payment default,
after three (3) Business Days (or, in the case on a non-payment default, fifteen
(15) days after written notice from Sublessor), it shall constitute a "Default"
under this Sublease, and Sublessor shall have all of the rights and remedies
available to the "Landlord" under the Base Lease, or at law or equity, for a
Default of Tenant thereunder as though Sublessor were "Landlord" and Sublessee
were "Tenant", including, without limitation, the rights and remedies set forth
in Section 13.1 of the Lease. The foregoing shall survive the expiration or
early termination of this Sublease.

         11.      Relationship of Parties. Building Services. Sublessee
recognizes that Sublessor is not the owner of the Subleased Premises, and that
the Landlord is the party with whom Sublessee would normally deal regarding
matters concerning the Subleased Premises and the Building, and that Sublessor
shall have no obligation to deliver or provide any services (including repairs)
to Sublessee or the Subleased Premises. Specifically, but without limitation,
with regard to the services and repairs to be provided by the Landlord under
Articles 7 and 12 of the Base Lease, Sublessee acknowledges that Landlord shall
be solely responsible for providing such services and repairs, and in the event
Sublessee desires any extra services (for example, additional air-conditioning
services) other than those provided to the Subleased Premises under the Base
Lease, has any complaints concerning any services or repairs required to be
provided by Landlord under the Base Lease to the Subleased Premises, or the
improvements thereto, or has any other matters which would normally be discussed
with a landlord, Sublessee agrees to contact Landlord directly to handle such
matters; it being the intention of the parties hereto that, as to such matters,
the only connection between Sublessee and Sublessor shall be (a) the
flow-through of rights and obligations of Sublessor under the Base Lease, and
(b) the payment of all amounts payable hereunder by Sublessee to Sublessor as
herein provided. Sublessee also acknowledges that all of the covenants and
obligations of Sublessor hereunder are expressly subject to the terms and
conditions of the Base Lease. As provided in Section 5 above, in the event
Sublessee acquires any additional services from Landlord for which additional
costs are incurred and Sublessee does not pay Landlord directly for such
services, then Sublessee shall pay Sublessor such amounts incurred by Sublessee
within ten (10) days following receipt from Sublessor of Landlord's invoice for
such services. If for any reason Sublessor receives an abatement of Base Rent
under the Base Lease, Sublessee shall receive an abatement of Base Rental under
this Sublease for the same period as Sublessor receives such abatement under the
Base Lease, to the extent the abatement received by Sublessor is attributable to
the Subleased Premises during the Sublease Term.

         12.      Holding Over. In the event Sublessee remains in possession of
the Subleased Premises after the expiration or earlier termination of this
Sublease, then Sublessee, at Sublessor's option, shall be deemed to be occupying
the Subleased Premises as a Sublessee at sufferance at a base rental equal to
one hundred and fifty percent (150%) of the Base Rental in

                                      -7-
<PAGE>

effect prior to expiration or termination, and shall otherwise remain subject to
all the conditions, provisions and obligations of this Sublease insofar as the
same are applicable to a tenancy at sufferance, including without limitation,
the payment of all additions to Base Rental provided and all other sums payable
hereunder. No holding over by Sublessee after the expiration or termination of
this Sublease shall be construed to extend or renew the Sublease Terra or in any
other manner be construed as permission by Sublessor to holdover. Sublessee
shall indemnify and hold Sublessor harmless from and against any and all damages
(actual, consequential or otherwise), losses, costs and expenses, including
reasonable attorneys' fees, incurred by Sublessor arising out of or in any way
attributable to such holding over.

         13.      Care of the Subleased Premises by Sublessee. Sublessee shall
maintain and repair the Subleased Premises in the manner required of Sublessor
by the Base Lease and shall not commit or allow any waste to be committed on any
portion of the Subleased Premises. At the expiration or earlier termination of
this Sublease, Sublessee shall surrender the Subleased Premises to Sublessor
broom clean and in good condition and state of repair, reasonable wear and tear
only excepted, and otherwise in the condition required under the Base Lease.

         14.      Incorporation of Base Lease Terms. Except for the Excluded
Provisions (defined below, none of which shall apply to this Sublease except as
otherwise expressly provided herein), to the extent not otherwise inconsistent
with the agreements and understandings expressed in this Sublease or applicable
only to the original parties to the Base Lease, the terms, provisions, covenants
and conditions of the Base Lease are hereby incorporated into this Sublease by
reference as fully as if completely reproduced herein, and for purposes of this
Sublease:

                  (a)      The term "Landlord" as used in the Base Lease shall
refer to Sublessor hereunder and its successors and assigns; the term "Tenant"
as used in the Base Lease shall refer to Sublessee hereunder; the term "Leased
Premises" as used therein shall refer to Subleased Premises herein;

                  (b)      In any case where Landlord reserves the right to
enter the Subleased Premises, said right shall inure to the benefit of Sublessor
as well as to Landlord;

                  (c)      Sublessee shall (i) maintain insurance as required
under the Base Lease in the amounts stated in the Base Lease, with Sublessor and
Landlord named as additional insureds and (ii) furnish to Sublessor certificates
of such insurance and other evidence satisfactory to Sublessor of the
maintenance of all insurance coverage required hereunder;

                  (d)      Sublessee hereby expressly assumes and agrees (i) to
perform all of the terms, obligations, covenants and conditions to be performed
by Sublessor pursuant to the Base Lease with respect to the Subleased Premises
or any of the common areas identified therein, and (ii) not to do, suffer or
permit anything to be done which would result in a default under the Base Lease
or cause the Base Lease to be terminated or forfeited, and, accordingly, except
as otherwise provided herein, Sublessee shall be entitled to all of the rights
and benefits of Sublessor as Tenant under the Base Lease with respect to the
Subleased Premises;

                                      -8-
<PAGE>

                  (e)      All indemnity obligations of Sublessee under the Base
Lease, as incorporated herein, shall be for the benefit of Sublessor, Landlord
and their employees;

                  (f)      To the extent that any notice or consent is required
under this Sublease, Sublessee shall provide copies of all such notices to
Landlord;

                  (g)      The parties to this Sublease agree to promptly
provide the other party with any notices received from Landlord which affect the
Subleased Premises;

                  (h)      With regard to Sections 10.1 and 14.24, and Articles
3 and 7 of the Base Lease, Sublessor shall have no obligations thereunder; and

                  (i) With regard to Article 12 of the Base Lease, Sublessor
shall have no obligations thereunder to repair or restore the Building or the
Leased Premises.

         As used herein, the term "Excluded Provisions" means Sections 1.2
(except for the definitions of Building Rentable Area, Business Days, Force
Majeure and Building Standard), 2.2(d), 3.1, 3.2, 3.3 (except for the first two
sentences thereof), 3.4, 3.5, 3.6,, 6.2(b), 6.3, 14.12, 14.17, 14.19,14.21,
14.24, and Articles 4, 15, 17, 18, and 19, and Exhibits A, C, H, L, and N.

         15.      Security Deposit.

                  (a) Contemporaneously with the execution of this Sublease,
Sublessee will deposit with Sublessor a security deposit in the amount of One
Million Three Hundred Thousand and No/100 Dollars ($1,300,000.00) (the "Security
Deposit"), as security for the faithful performance of Sublessee's obligations
hereunder. The Security Deposit and any amount drawn thereon shall not be
considered an advance payment of Base Rental or Additional Charges, and the
Security Deposit shall not be considered a measure of Sublessor's damages in
case of the occurrence of any default under this Sublease. In the event
Sublessee defaults in respect to any of the terms, provisions, agreements,
covenants and conditions of this Sublease including, but not limited to, the
payment of any amounts owed by Sublessee for Base Rental or Additional Charges
and such default continues uncured after the expiration of all applicable notice
and cure periods herein provided, Sublessor may, at Sublessor's option, from
time to time, without prejudice to any other remedy, apply the amounts necessary
to make good any arrears of amounts owing in relation to Base Rental or
Additional Charges or for any damage, injury, expense or liability caused by
such default. Following any such application, Sublessee shall pay to Landlord on
demand the amount so applied in order to restore the Security Deposit to its
original amount.

                  (b) The Security Deposit may be delivered in the form of an
unconditional and irrevocable letter of credit (together with any renewals or
replacements therefor, the "Letter of Credit") issued by and drawn upon a
commercial bank reasonably acceptable to Sublessor (the "Issuing Bank"), which
shall (1) name Sublessor as beneficiary thereof and be irrevocable, (2) have an
initial expiration date that is April 30, 2005 or later, (3) be in the amount of
One Million Three Hundred Thousand and No/100 Dollars ($1,300,000.00), and (4)
otherwise be in form and content reasonably acceptable to Sublessor. The Letter
of Credit shall in any event provide that:

                                      -9-
<PAGE>

                           i.       The Issuing Bank shall pay to Sublessor an
         amount up to the face amount of the Letter of Credit upon presentation
         of a sight draft and Beneficiary's Certificate to the Issuing Bank as
         stated in the Standby Letter of Credit attached hereto as Exhibit D;

                           ii.      The Letter of Credit shall be automatically
         renewed, without amendment, for consecutive periods of one year each
         and shall have a final expiry date of not earlier than sixty (60) days
         after the expiration of the Sublease Term, unless the Issuing Bank
         sends written notice (the "Non-Renewal Notice") to Sublessor both by
         Federal Express or other recognized national or regional courier and by
         certified or registered mail, return receipt requested, not less than
         sixty (60) days before the then expiration date of the Letter of
         Credit, that the Issuing Bank will not renew the Letter of Credit; and

                           iii.     Sublessor, after receipt of a Non-Renewal
         Notice, or within sixty (60) days prior to the expiration date of any
         Letter of Credit then held by Sublessor, shall have the right to draw
         upon the Letter of Credit and receive the proceeds thereof (which shall
         be held by Sublessor as a cash deposit pursuant to the terms of this
         Section 15 pending the replacement of such Letter of Credit or applied
         as permitted by the terms of this Section 15).

         (c)      Sublessee hereby grants to Sublessor a security interest in
the Security Deposit, the Letter of Credit, and in and to all proceeds thereof.
Sublessee covenants that it will not assign or encumber the Security Deposit,
the Letter of Credit, any substitute therefor, or any proceeds thereof, and that
neither Sublessor nor its successors or assigns will be bound by any such
assignment, encumbrance, attempted assignment or attempted encumbrance. Any fee
payable to the Issuing Bank on a transfer of the Letter of Credit shall be
payable by Sublessee, and if not paid by Sublessor may be paid by Sublessor and
Sublessee shall within fifteen days after invoice reimburse Sublessor for such
fees.

         (d)      Sublessor shall, without prejudice to any other remedy
Sublessor may have hereunder, at law or at equity, apply the proceeds of the
Letter of Credit, or any part thereof, to Sublessor's damages arising from, or
to cure, any event of Default of Sublessee hereunder. Upon application of such
proceeds, Sublessee shall promptly deposit with Sublessor the amount applied to
be held as security hereunder or obtain a replacement Letter of Credit in such
amount conforming with the other requirements of this Section.

         (e)      Provided no event of Default of Sublessee then exists, then
the Letter of Credit may be reduced on April 1, 2006, to Five Hundred Thousand
and No/100 Dollars ($500,000.00) by delivery to Sublessor by Sublessee of a
substitute Letter of Credit in form and content reasonably acceptable to
Sublessee. Sublessor shall have no obligation to return any Letter of Credit in
its possession until Sublessee has delivered a substitute Letter of Credit;
however, Sublessor shall return any Letter of Credit for which replacement or
substitution has been made by Sublessee in accordance with this Section.

         (f)      Provided no event of Default of Sublessee then exists,
Sublessor shall return the Letter of Credit, or so much thereof as shall not
have been applied in accordance with the terms

                                      -10-
<PAGE>

of this Section, to Sublessee within thirty (30) days after the expiration or
other termination of the Sublease Term and surrender of the Subleased Premises
to Sublessor.

         16.      Representations and Warranties.

                  (a)      Sublessor warrants and represents to Sublessee as
         follows:

                           (i)      Sublessor is a corporation duly organized
         under the laws of Delaware and has full right, power and authority to
         enter into this Sublease and to carry out its obligations hereunder and
         all required corporate actions necessary to authorize Sublessor to
         enter into this Sublease and to carry out its obligations hereunder
         have been taken.

                           (ii)     Attached hereto as Exhibit B is a true and
         complete copy of the Base Lease, including all amendments or
         modifications thereto, which constitute all written agreements between
         Landlord and Sublessor affecting the Subleased Premises.

                           (iii)    No Default of Tenant by Sublessor exists
         under the Base Lease, and no event has occurred that with the giving of
         notice or passage of time would constitute such a Default of Tenant
         under the Base Lease and to the knowledge of Sublessor, Landlord is not
         in default under the Base Lease, except that there exists a dispute
         between Sublessor and Landlord as to the calculation of Base Taxes and
         related issues under the Base Lease, with a resulting amount of Taxes
         having been paid in protest by Sublessor. Resolution of this issue will
         not alter the amounts payable by Sublessee under this Sublease.

                  (b)      Sublessee warrants and represents to Sublessor as
         follows:

                           (i)      Sublessee is a corporation duly organized
         under the laws of Delaware and has full right power and authority to
         enter into this Sublease and to carry out its obligations hereunder and
         all required corporate actions necessary to authorize Sublessee to
         enter into this Sublease and to carry out its obligations hereunder
         have been taken.

                           (ii)     Sublessee has reviewed the terms of the Base
         Lease.

                           (iii)    Sublessee covenants and agrees to timely
         perform its obligations under this Sublease.

         17.      Notices. All notices or requests provided for hereunder shall
be in writing and shall be either (a) delivered by hand, (b) sent by United
States Registered or Certified Mail, return receipt requested, postage prepaid,
or (c) sent by prepaid nationally recognized overnight carrier, if to Sublessor,
to 2101 CityWest Blvd., Houston, Texas 77042, Attn: Manager of Corporate Real
Estate; or if to Sublessee until the Commencement Date, 1440 Main Street,
Waltham, Massachusetts 02451, Attention: Ari Buchler, Vice President and General
Counsel; and after the Commencement Date, to 880 Winter Street, Waltham,
Massachusetts 02451, Attention: Ari Buchler, Vice President and General Counsel.
A copy of all such notices shall be

                                      -11-
<PAGE>

sent to Anne Newtown, Vinson & Elkins LLP, 1001 Fannin, Suite 2300, Houston,
Texas 77002 and to Douglas M. Henry, Testa, Hurwitz & Thibeault, LLP, 125 High
Street, Boston, Massachusetts 02110. All such notices shall be deemed received
either when hand delivered if sent in the manner provided in (a) above, two (2)
business days after being placed in the United States Mail if sent in the manner
set forth in (b) above or upon delivery or attempted delivery if sent in the
manner provided in (c) above. The parties hereto shall have the right from time
to time to change their respective address by at least five (5) days prior
written notice to the other party.

         18.      Governing Law. THIS SUBLEASE SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF MASSACHUSETTS.

         19.      Interest on Sublessee's Obligations. Unless otherwise provided
for, all amounts owed by Sublessee to Sublessor under this Sublease shall bear
interest from the date due until paid at the lesser of (i) twelve percent (12%)
per annum or (ii) the maximum lawful contract rate per annum. In no event,
however, shall the charges permitted under this Section or elsewhere in this
Sublease, to the extent they are considered to be interest under applicable law,
exceed the maximum lawful rate of interest.

         20.      Severability. In the event that any one or more of the
provisions contained in this Sublease shall be held to be invalid, illegal, or
unenforceable in any respect, such invalidity, illegality, or unenforceability
shall not affect any other provision hereof, and this Sublease shall be
construed as if such invalid, illegal, or unenforceable provision had never been
contained herein.

         21.      Attorneys' Fees. If any action at law or in equity, including
an action for declaratory relief, is brought to enforce or interpret the
provisions of this Sublease, the prevailing party shall be entitled to recover
reasonable attorneys' fees from the other party.

         22.      Amendments. This Sublease may not be altered, changed or
amended, except by an instrument in writing executed by all parties hereto.

         23.      NO REPRESENTATIONS OR WARRANTIES. SUBLESSEE HEREBY EXPRESSLY
ACKNOWLEDGES AND AGREES THAT SUBLESSOR HAS MADE NO REPRESENTATIONS OR WARRANTIES
TO SUBLESSEE AS TO THE USE OR CONDITION OF THE SUBLEASED PREMISES OR THE
BUILDING OR AS TO THE ADEQUACY OF ANY EQUIPMENT (INCLUDING THE HEATING,
VENTILATING OR AIR CONDITIONING EQUIPMENT), EITHER EXPRESS OR IMPLIED, AND
SUBLESSOR EXPRESSLY DISCLAIMS ANY IMPLIED WARRANTY THAT THE SUBLEASED PREMISES
ARE SUITABLE FOR SUBLESSEE'S INTENDED COMMERCIAL PURPOSE OR ANY OTHER IMPLIED
WARRANTY REGARDING THE SUBLEASED PREMISES. IN ADDITION, EXCEPT AS HEREIN
EXPRESSLY PROVIDED IN SECTIONS 7.6 AND 12.1 OF THE BASE LEASE, AS INCORPORATED
HEREIN, SUBLESSEE EXPRESSLY ACKNOWLEDGES AND AGREES THAT SUBLESSEE'S OBLIGATION
TO PAY BASE RENTAL OR ANY OTHER SUMS DUE HEREUNDER IS NOT DEPENDENT UPON THE

                                      -12-
<PAGE>

CONDITION OF THE SUBLEASED PREMISES OR THE PERFORMANCE BY SUBLESSOR OF ITS
DUTIES OR OBLIGATIONS HEREUNDER (OR BY LANDLORD OF ITS DUTIES OR OBLIGATIONS
UNDER THE BASE LEASE), AND THAT SUBLESSEE WILL CONTINUE TO PAY BASE RENTAL AND
ALL OTHER SUMS PROVIDED FOR HEREIN TO BE PAID BY SUBLESSEE WITHOUT ABATEMENT,
SET-OFF, OR DEDUCTION, NOTWITHSTANDING ANY BREACH BY SUBLESSOR OF ITS DUTIES OR
OBLIGATIONS HEREUNDER (OR BY LANDLORD OF ITS DUTIES OR OBLIGATIONS UNDER THE
BASE LEASE), EXPRESS OR IMPLIED. SUBLESSOR AND SUBLESSEE EXPRESSLY AGREE THAT
THERE ARE AND SHALL BE NO IMPLIED WARRANTIES OF MERCHANTABILITY, HABITABILITY,
FITNESS FOR A PARTICULAR PURPOSE OR ANY OTHER KIND ARISING OUT OF THIS SUBLEASE
AND THAT ALL EXPRESS OR IMPLIED WARRANTIES IN CONNECTION HEREWITH ARE EXPRESSLY
DISCLAIMED.

         24.      Quiet Enjoyment. Provided Sublessee has performed all of the
terms, covenants, agreements and conditions of this Sublease Agreement,
Sublessee shall peaceably and quietly hold and enjoy the Subleased Premises
against Sublessor and all persons claiming by, through or under Sublessor, for
the Sublease Term herein described, subject to the provisions and conditions of
this Sublease and of the Base Lease.

         25.      Entire Agreement. This Sublease constitutes the entire
agreement between Sublessee and Sublessor and supersedes all prior agreements
(whether written or otherwise) that may exist between the parties with regard to
the Sublease and use of the Subleased Premises by Sublessee.

         26.      Consent by Landlord. This Sublease shall be effective only
upon Landlord's consent hereto evidenced by a separate document executed by
Landlord satisfactory to Sublessee and Sublessor in their reasonable judgment.
If Landlord does not give its written consent or Landlord's consent is not
deemed to be given by December 31, 2003, such consent will be deemed denied and
this Sublease will terminate, the Security Deposit shall be returned by
Sublessor to Sublessee, the Tenant Improvement Allowance shall be returned by
Sublessee to Sublessor, and neither party shall have any additional obligations
hereunder. Any costs or expenses required to be paid to Landlord pursuant to
Section 6.5(a) of the Base Lease, in connection with Landlord's processing and
documentation of this Sublease shall be borne and paid by one-half by each of
Sublessor and Sublessee.

         27.      Brokers. Sublessee acknowledges that Cushman & Wakefield of
Massachusetts, Inc. ("Sublessor's Broker") is representing the Sublessor
regarding this Sublease and Trammell Crow Company ("Sublessee's Broker") is
representing the Sublessee regarding the Sublease (collectively the "Brokers").
Sublessee warrants and represents that it has not dealt with any other real
estate broker and/or salesman in connection with the negotiation or execution of
this Sublease other than Sublessee's Broker and no such broker or salesman has
been involved in connection with this Sublease. Sublessor warrants and
represents that it has not dealt with any other real estate broker and/or
salesman in connection with the, negotiation or execution of this Sublease other
than Sublessor's Broker and no such broker or salesman has been involved in
connection with this Sublease. The Brokers are being compensated pursuant to a
separate

                                      -13-
<PAGE>

agreement with Sublessor. Sublessee agrees to defend, indemnify and hold
harmless the Sublessor from and against any and all costs, expenses, attorneys'
fees or liability for any compensation, commission and charges claimed by any
real estate broker and/or salesman (other than the Brokers), due to acts of
Sublessee or Sublessee's representatives. Sublessor agrees to defend, indemnify
and hold harmless Sublessee from and against any and all costs, expenses,
attorney's fees or liability for any compensation, commission and charges
claimed by any real estate broker and/or salesman (including, without
limitation, the Brokers) due to acts of Sublessor or Sublessor's
representatives.

         28.      Parking. Subject in all respects to the terms of the Base
Lease, Sublessee shall have the right (subject to the Rules and Regulations from
time to time established by Landlord) to use, on a non-exclusive unreserved
basis and in common with use by other tenants of the Complex, parking spaces
that Sublessor may be entitled to use under the terms of the Base Lease in the
parking areas located in the Complex, which, when aggregated with all other
parking spaces that Sublessee is permitted to use hereunder, no more than 3.3
parking spaces per 1,000 rentable square feet in the Subleased Premises, of
which up to 75 parking spaces may be located in the basement level of the
Building; accordingly, the number of unreserved parking spaces that Sublessee
shall be entitled to use hereunder is 327 unreserved spaces. During the Sublease
Term, Sublessee shall be entitled to use such parking spaces at no additional
charge. Sublessee's use of parking spaces hereunder shall be subject to all
other terms and conditions set forth in the Base Lease.

         29.      Signage. Subject to Landlord's and Sublessor's approval (which
Sublessor's approval shall not be unreasonably withheld, delayed or conditioned)
of the design, size and location thereof, and compliance with Building sign
criteria and applicable laws, Sublessee may, at Sublessee's sole cost and
expense, place Sublessee's corporate name (a) on or beside the main entrance to
the Subleased Premises (similar to Sublessor's existing glass signage on the
first floor of the Subleased Premises), and (b) on the existing monument sign
used by Sublessor. Sublessee shall also have the right, as Sublessee's sole cost
and expense, to have Sublessee's name displayed on the Building directory
maintained for tenants of the Building. Sublessor agrees to utilize its
reasonable commercial efforts to assist Sublessee in obtaining the foregoing
signage rights from landlord, but with no obligation to incur any liability or
expense or undertake any obligation.

         30.      Right of First Offer.

                  (a)      Subject to the rights of any existing or future
subtenants of Sublessor, provided no event of Default exists as of the date on
which Sublessee exercises its option under this Section 30 or on the date on
which a lease of First Offer Space commences hereunder, throughout the Sublease
Term Sublessee shall have a continuous and recurring right of first offer (the
"Right of First Offer") to lease any space within the Leased Premises that may
come available during the Term of this Sublease at the then current Fair Market
Rental Value (as defined in the Base Lease), and otherwise on the same terms and
conditions set forth in this Sublease.

                                      -14-
<PAGE>

                  (b)      Upon Sublessee's written request therefor, from time
to time during the Sublease Term (but not more often that twice in any twelve
(12) month period), Sublessor will provide to Sublessee a written notice (the
"First Offer Notice") of all available space in the Leased Premises (the "First
Offer Space") and the terms and conditions on which Sublessor is then marketing
such space to prospective subtenants, and shall offer to Sublessee subject to
the provisions of this Section 30, the right to add such First Offer Space to
the Subleased Premises. The First Offer Notice shall specify the First Offer
Space, the date such First Offer Space shall become available for Sublessee's
occupancy (the "First Offer Sublease Date") and Sublessor's calculation of Fair
Market Rental Value. The First Offer Space will be offered for a term that is
coterminous with the Sublease Term. Sublessee may, by delivering to Sublessor a
written notice (the "Sublessee's Offer Notice") within twenty (20) days after
delivery of the First Offer Notice to Sublessee, either (i) accept the offer set
forth in the First Offer Notice or (ii) elect to lease all or a part of the
First Offer Space and provide Sublessor with its determination of Fair Market
Rental Value for the First Offer Space, whereupon the Fair Market Rental Value
shall be submitted to the process set forth in Article 16 of the Base Lease.
Each of Sublessor's and Sublessee's notice to the other setting forth their
respective determination of Fair Market Rental Value for the First Offer Space
shall constitute each of Sublessor's and Sublessee's "Determination Notice" for
purposes of Article 16 of the Base Lease. If Sublessee does not give Sublessee's
Offer Notice or fails timely to deliver such First Offer Notice pursuant to the
provisions of this Section 30, Sublessor shall be free, subject to the
provisions of Section 31 of this Sublease, to sublease such First Offer Space at
any time during the six (6) months following the expiration of such 20 day
period on such terms as Sublessor, in it's sole discretion, deems reasonable. If
no sublease is consummated within such 6 month period, the requirements of this
Section 30 shall again be applicable.

         31.      Right of First Refusal. Subject to the rights of any existing
or future subtenants of Sublessor, provided no event of Default exists as of the
date on which Sublessee exercises its option under this Section 31 or on the
date on which a lease of First Refusal Space commences hereunder, if during the
Sublease Term, Sublessor receives from any third party an offer to sublease all
or any portion of the Leased Premises that is not leased to Sublessee hereunder
(the portion of the Leased Premises that is the subject of any such offer is
hereinafter referred to as the "First Refusal Space"), which offer Sublessor
desires to accept, Sublessor shall deliver to Sublessee written notice (the
"First Refusal Notice") of the terms and conditions of such offer, including,
without limitation, identification of the First Refusal Space to be subleased,
the Base Rental rate, and any other pertinent terms of such offer, and
Sublessor, subject to the provisions of this Section 31, shall offer to
Sublessee the right to add such First Refusal Space to the Subleased Premises
upon the same terms and conditions as set forth in the First Refusal Notice as
to the payment of rent, security and other commercial terms, but otherwise as
the same terms and conditions as this Sublease. Upon receipt of any such First
Refusal Notice from Sublessor, Sublessee shall have ten (10) days thereafter
within which to accept the same. If Sublessee fails to accept any such offer
within such 10 day period, Sublessor shall be free to sublease to the original
offeror for such First Refusal Space at any time during the twelve (12) months
following the expiration of such 10 day period, without further notice to
Sublessee, on the same terms and conditions set out in the First Refusal Notice,
or on such other terms and conditions that are not materially more favorable
than the terms and conditions set out in the First Refusal Notice (a "Complying
Sublease"). If a Complying Sublease is not consummated within such 12 month

                                      -15-
<PAGE>

period, the requirements of this Section 31 shall again be applicable and
Sublessor shall, prior to the sublease of any of the Leased Premise, re-offer
the same to Sublessee in accordance with the provisions of this Section 31. If
Sublessee accepts an offer pursuant to the terms hereof, the First Refusal Space
will be made a part of the Subleased Premises.

         32.      Personal Property. In addition to the Subleased Premises,
Sublessee shall have the right to use, during the Sublease Term, at no
additional charge, the furniture, fixtures, equipment, and other personal
property listed on Exhibit C attached hereto (the "Personal Property"), which is
located in the Subleased Premises; however, all such Personal Property shall
remain the property of Sublessor and shall be returned to Sublessor upon the
expiration or earlier termination of this Sublease in as good condition as
existed as of the date of this Sublease, reasonable wear and tear excepted.
Sublessee shall not remove any of the Personal Property from the Subleased
Premises without Sublessor's prior written consent. Sublessee shall repair any
damage to any of the Personal Property that occurs during the Sublease Term
(reasonable wear and tear excepted), which obligation shall survive the
expiration or other termination of this Sublease. Sublessee will insure such
Personal Property at full replacement cost during the Sublease Term. Sublessee
acknowledges that Sublessee has inspected the Personal Property and accepts it
in its "As Is" condition, and acknowledges that Sublessor has made no
representations or warranties, either express or implied, written or oral, with
respect to the condition of the Personal Property or its suitability for any use
or purpose by Sublessee.

                            [Signature Page Follows]

                                      -16-
<PAGE>

         EXECUTED in multiple counterparts, each of which shall have the force
and effect of an original, as of the date first set forth above.

                                       SUBLESSOR:

                                       BMC SOFTWARE, INC.,
                                       a Delaware corporation

                                       BY:/s/ John W. Cox
                                          ---------------------
                                       Name: John W. Cox
                                       Title: CFO

                                       SUBLESSEE:

                                       PHASE FORWARD INCORPORATED
                                       a Delaware corporation

                                       By:_____________________
                                       Name:___________________
                                       Title:__________________

                                      -17-
<PAGE>

         EXECUTED in multiple counterparts, each of which shall have the force
and effect of an original, as of the date first set forth above.

                                       SUBLESSOR:

                                       BMC SOFTWARE, INC.,
                                       a Delaware corporation

                                       By:____________________
                                       Name:__________________
                                       Title:_________________

                                       SUBLESSEE:

                                       PHASE FORWARD INCORPORATE
                                       a Delaware corporation

                                       By: /s/ William G. Porter
                                          ------------------------
                                       Name: William G. Porter
                                       Title: Vice President, Finance
                                              Phase Forward Incorporated

                                      -17-
<PAGE>

                                    EXHIBIT A

                                    PREMISES

                                      A-1-
<PAGE>

EXHIBIT A

                               PHASE FORWARD SPACE

                           [MAP OF FIRST FLOOR PLAN]

<PAGE>

                              PHASE FORWARD SPACE

                           [MAP OF SECOND FLOOR PLAN]

<PAGE>

                                   EXHIBIT B

                              [Base Lease attached]

                                      B-1-
<PAGE>

                                    LEASE OF

                                880 WINTER STREET

                             WALTHAM, MASSACHUSETTS

                                     BETWEEN

                          BGS SYSTEMS, INC., AS TENANT

                                       AND

                     880 WINTER STREET, L.L.C., AS LANDLORD

                                 JULY 15, 1998

<PAGE>

                                                                         TENANT:
                                                               BGS Systems, Inc.

                                    LEASE OF

                                880 WINTER STREET

                             WALTHAM, MASSACHUSETTS

                                TABLE OF CONTENTS

<TABLE>
<S>                                                             <C>
ARTICLE 1
  BASIC LEASE PROVISIONS.....................................
      1.1      INTRODUCTION..................................
      1.2      BASIC DATA....................................
      1.3      ENUMERATION OF EXHIBITS.......................
      1.4      OTHER DEFINITIONS.............................

ARTICLE 2
  PREMISES AND APPURTENANT RIGHTS............................
      2.1      LEASE OF PREMISES.............................
      2.2      APPURTENANT RIGHTS AND RESERVATIONS...........

ARTICLE 3
  LEASE TERM AND BUILDING/PREMISES
    CONSTRUCTION.............................................
      3.1      LEASE-TERM................................. ..
      3.2      PREPARATION OF THE PREMISES...................
      3.3      QUALITY AND PERFORMANCE.......................
               OF WORK/CONCLUSIVENESS........................
               OF LANDLORD'S PERFORMANCE.....................
      3.4      TENANT'S DELAYS...............................
      3.5      TENANT ENTRY FOR FURNISHING...................
      3.6      MULTIPLE CONSTRUCTION PHASES..................

ARTICLE 4
  BASIC RENT.................................................
      4.1      PAYMENT.......................................
      4.2      RENT CREDITS..................................

ARTICLE 5
  USE OF PREMISES............................................
      5.1      PERMITTED USE.................................
      5.2      INSTALLATIONS AND ALTERATIONS BY TENANT.......

ARTICLE 6
  ASSIGNMENT AND SUBLETTING..................................
      6.1      PROHIBITION...................................
      6.2      CONSENT TO SUBLEASE...........................
      6.3      EXCESS PAYMENTS...............................
</TABLE>

<PAGE>

<TABLE>
<S>                                                             <C>
      6.4      TERMINATION...................................
      6.5      MISCELLANEOUS.................................
      6.6      ACCEPTANCE OF RENT............................

ARTICLE 7
  REPAIRS AND SERVICES.......................................
      7.1      LANDLORD REPAIRS..............................
      7.2      TENANT REPAIRS................................
      7.3      FLOOR LOAD - HEAVY MACHINERY..................
      7.4      BUILDING SERVICES.............................
      7.5      ELECTRICITY...................................
      7.6      INTERRUPTION OF SERVICES......................

ARTICLE 8
  REAL ESTATE TAXES..........................................
      8.1      DEFINITIONS ..................................
      8.2      TENANT'S SHARE OF TAXES.......................
      8.3      REFUND OF TAXES...............................

ARTICLE 9
  OPERATING EXPENSES.........................................
      9.1      DEFINITIONS  .................................
      9.2      EXCESS OPERATING EXPENSES.....................
      9.3      TENANT'S AUDIT RIGHTS.........................

ARTICLE 10
  INDEMNITY AND INSURANCE....................................
      10.1     TENANT'S AND LANDLORD'S INDEMNITY.............
      10.2     GENERAL LIABILITY INSURANCE...................
      10.3     TENANT'S RISK.................................
      10.4     CERTIFICATES OF INSURANCE.....................
      10.5     INJURY CAUSED BY THIRD PARTIES................
      10.6     WAIVER OF SUBROGATION.........................

ARTICLE 11
  LANDLORD'S ACCESS TO PREMISES..............................
      11.1     LANDLORD'S RIGHT OF ENTRY.....................
      11.2     LANDLORD'S RIGHT TO CHANGE ENTRIES,
               ETC. .........................................
      11.3     EXCAVATION

ARTICLE 12
  FIRE, EMINENT DOMAIN, ETC. ................................
      12.1     ABATEMENT OF RENT.............................
      12.2     LANDLORD'S RIGHT OF TERMINATION...............
      12.3     RESTORATION ..................................
      12.4     AWARD... .....................................
      12.5     LANDLORD'S INSURANCE..........................
</TABLE>

<PAGE>

<TABLE>
<S>                                                             <C>
ARTICLE 13
  DEFAULT....................................................
      13.1     TENANT'S DEFAULT..............................
      13.2     LANDLORD'S DEFAULT............................

ARTICLE 14
  MISCELLANEOUS PROVISIONS...................................
      14.1     EXTRA HAZARDOUS USE...........................
      14.2     WAIVER........................................
      14.3     COVENANT OF QUIET ENJOYMENT...................
      14.4     LANDLORD'S LIABILITY..........................
      14.5     NOTICE TO MORTGAGEE OR GROUND
               LESSOR........................................
      14.6     ASSIGNMENT OF RENTS AND
               TRANSFER OF TITLE.............................
      14.7     RULES AND REGULATION..........................
      14.8     ADDITIONAL CHARGES............................
      14.9     INVALIDITY OF PARTICULAR PROVISIONS...........
      14.10    PROVISIONS BINDING. ETC.......................
      14.11    RECORDING.....................................
      14.12    NOTICES.......................................
      14.13    WHEN LEASE BECOMES BINDING....................
      14.14    PARAGRAPH HEADINGS AND
               INTERPRETATION OF SECTIONS....................
      14.15    RIGHTS OF MORTGAGEE OR GROUND
               LESSOR.......................................
      14.16    STATUS REPORT.................................
      14.17    SECURITY DEPOSIT..............................
      14.18    REMEDYING DEFAULTS............................
      14.19    HOLDING OVER..................................
      14.20    SURRENDER OF PREMISE..........................
      14.21    BROKERAGE.....................................
      14.22    GOVERNING LAW.................................
      14.23    FINANCIAL STATEMENT...........................
      14.24    YEAR 2000.....................................

ARTICLE 15
  OPTIONS TO EXTEND..........................................
      15.1     TENANT'S RIGHT................................
      15.2     EXTENDED TERM RENT............................

ARTICLE 16
  FAIR MARKET RENTAL VALUE...................................
      16.1     DEFINITION....................................

ARTICLE 17
  EXPANSION OPTIONS..........................................
      17.1     FIRST EXPANSION SPACE.........................
      17.2     TENANT'S FIRST EXPANSION NOTICE...............
      17.3     EFFECT OF INCLUSION...........................
      17.4     SECOND EXPANSION SPACE........................
      17.5     TENANT'S SECOND EXPANSION NOTICE..............
      17.6     EFFECT OF INCLUSION...........................
</TABLE>

<PAGE>

<TABLE>
<S>                                                             <C>
      17.7     THIRD EXPANSION SPACE.........................
      17.8     TENANT'S THIRD EXPANSION NOTICE...............
      17.9     EFFECT OP INCLUSION...........................
      17.10    CONDITION OF EXPANSION SPACE..................
      17.11    NO BROKERS....................................
      17.12    OFFERED LEASE AMENDMENT.......................
      17.13    MISCELLANEOUS.................................

ARTICLE 18
  RIGHT OF FIRST OFFERING....................................
      18.1     FIRST OFFERING SPACE..........................
      18.2     TENANT'S OFFERING NOTICE......................
      18.3     EFFECT OF INCLUSION...........................
      18.4     CONDITION OF FIRST OFFERING SPACE.............
      18.5     NO BROKERS....................................
      18.6     RIGHT OF OFFERING LEASE AMENDMENT.............
      18.7     MISCELLANEOUS.................................

ARTICLE 19
  SIGNAGE....................................................

ARTICLE 20
  ADDITIONAL EQUIPMENT.......................................

ARTICLE 21
  ARBITRATION................................................
</TABLE>

<PAGE>

                                      LEASE

     THIS INSTRUMENT IS A LEASE, dated as of July __,  1998, in which the
Landlord and the Tenant are the parties  hereinafter named, and which relates to
space in a certain building (the  "Building")  known as, and with an address at,
880 Winter Street, Waltham, Massachusetts,  being located in a multiple building
office park known as Waltham Woods Corporate Center (the "Complex"). The parties
to this instrument hereby agree with each other as follows:

ARTICLE 1

                             BASIC LEASE PROVISIONS

1.1      INTRODUCTION. The following act forth basic data and identifying
         Exhibits elsewhere hereinafter referred to in this Lease, and, where
         appropriate, constitute definitions of the terms hereinafter listed.

1.2      BASIC DATA

         Landlord:                      880 Winter Street, L.L.C.,
                                        a Delaware limited liability company

         Landlord's Original Address:   c/o Leggat McCall Properties, LP.,
                                        10 Post Office Square, Boston. MA 02109

         Landlord's Construction        Leggat McCall Properties Management,LP.,
         Representative:                880 Water Street, Waltham, MA

         Tenant:                        BGS Systems. Inc., a Massachusetts
                                        corporation

         Tenant's Original Address:     One First Avenue, Waltham, MA 02154

         Tenant's Construction
         Representative:                Tishman Construction Corporation of
                                        Massachusetts, 84 State Street, Boston,
                                        MA 02109

         Guarantor:                     BMC Software. Inc., a Delaware
                                        corporation

         Guarantor Address:             2101 CityWest Boulevard, Houston,
                                        TX 77042

         Premises:                      The entire first and second floors of
                                        the Building and a portion of the third
                                        floor of the Building as more
                                        particularly shown on Exhibit A annexed
                                        hereto and made a part hereof

         Premises Rentable Area:        Agreed to be 175,584 rentable square
                                        feet (62,092 rentable square feet on the
                                        first floor of the Building, 77,817
                                        rentable square feet on the second floor
                                        of the Building and 35,675 rentable
                                        square feet on the third floor of the
                                        Building), as

<PAGE>

                                        measured in accordance with the
                                        Measurement Method.

         Basic Rent:                    (1) (a) Subject to the credits set forth
                                        in Section 4.2 of the Lease, from the
                                        Commencement Date to the last day of the
                                        month in which occurs the third
                                        anniversary thereof, $5,618,688 per
                                        annum ($32.00 per square foot of
                                        Premises Beatable Area per annum); (b)
                                        for the next twenty-four (24) months,
                                        $5,794,272 per annum ($33.00 per square
                                        foot of Premises Rentable Area per
                                        annum); (c) for the next twenty-four
                                        (24) months, $5,969,856 per annum
                                        ($34.00 per square foot of Premises
                                        Rentable Area per annum); and (d) for
                                        the balance of the initial Lease. Term,
                                        $6,145,440 per annum ($35.00 per square
                                        foot of Premises Rentable Area), as the
                                        same may be adjusted and/or abated
                                        pursuant to Section 12.1, and as such
                                        may be adjusted in the Extended Term(s)
                                        or by virtue of Tenant's exercise of any
                                        expansion option or right of first offer
                                        hereunder.

         Estimated Electricity Payment. Initially $149,246.40 per annum
                                        (eighty-five cents ($0.85) per square
                                        foot of Premises Rentable Area per
                                        annum) as a payment toward the actual
                                        cost of providing electricity to the
                                        Premises, as the flame may be adjusted
                                        and/or abated pursuant to Sections 7.5
                                        and 12.1, and as the same may be
                                        adjusted in the Extended Term(s) or by
                                        virtue of Tenant's exercise of any
                                        expansion option or right of first offer
                                        hereunder.

         Additional Charges:            The Estimated Electricity Payment and
                                        Landlord charges and other sums payable
                                        by Tenant as set forth in this Lease,
                                        including, without limitation, the
                                        charges for Taxes and Operating Expenses
                                        as set forth in Sections 8.2 and 9.2,
                                        respectively, other than and in addition
                                        to Bask Rent.

         Lease Term:                    Commencing with the Commencement Date
                                        and expiring on the last day of the
                                        calendar month which is ten (10) years
                                        and four (4) months after the
                                        Commencement Date, as such may be
                                        extended pursuant to the Tenant's
                                        Extended Term options, or on such
                                        earlier date upon which the Lease Term
                                        may expire or be terminated pursuant to
                                        any of the conditions or other
                                        provisions of this Lease or pursuant to
                                        law.

         Security Deposit:              Initially none, subject to adjustment as
                                        set forth in Section 14.47 hereof.

                                      -2-
<PAGE>

         Broker:                        Cushman Realty Corporation, Fallon Hines
                                        & O'Connor and Leggat McCall Properties
                                        Management, L.P.

         Agent:                         Leggat McCall Properties Management,
                                        L.P., 880 Winter Street, Waltham, MA,
                                        Attn: Property Manager, or such other
                                        person or entity from time to time
                                        designated by Landlord.

         Building Rentable Area:        agreed to be 218,584 square feet, as
                                        measured in accordance with the
                                        Measurement Method.

         Business Days:                 All days except Saturday, Sunday, New
                                        Year's Day, Memorial Day, Independence
                                        Day, Labor Day, Thanksgiving Day,
                                        Christmas Day (and the following day
                                        when any such day occurs on a Sunday).

         Commencement Date:             As defined in Section 3.1.

         Default of Tenant:             As defined in Section 18.1.

         Force Majeure:                 Collectively and individually, strikes
                                        or other labor trouble, fire or other
                                        casualty, acts of God, governmental
                                        preemption of priorities or other
                                        controls in connection with a national
                                        off other public emergency or shortages
                                        of fuel, supplies or labor resulting
                                        therefrom, or any other similar
                                        cause-beyond Landlord's or Tenant's
                                        reasonable control.

         Initial General Liability
           Insurance:                   $3,000,000 per occurrence/ $5,000,000
                                        aggregate (combined single limit) for
                                        property damage, bodily injury or death.

         Measurement Method:            "Standard Method for Measuring Floor
                                        Area in Office buildings" (Reprinted
                                        August 1990, American National Standard
                                        ANSI Z65.1-1980) (Reaffirmed 1989).
                                        Approved June 21, 1989 by American
                                        National Standards Institute, Inc.)
                                        prepared for the Building Owners and
                                        Managers Association International

         Landlord's Contribution:       An amount equal to $29.50 per square
                                        foot of Premises Rentable Area.

         Operating Year:                As defined in Section 9.1.

         Operating Expenses:            As defined in Section 9.1.

         Base Operating Expenses:       Operating Expenses incurred for the
                                        calendar Year Ending December 31,1999,
                                        adjusted to 100%

                                      -3-
<PAGE>

                                        occupancy for those expenses which vary
                                        with occupancy levels, and as more
                                        particularly defined in Section 9.1.

         Building Operating Expenses:   As defined in Section 9.1.

         Common Site Operating
         Expenses:                      As defined in Section 9.1.

         Permitted Uses:                Executive and general offices of the
                                        type generally found in first-class
                                        office buildings in the suburban Boston
                                        area subject to the provisions of
                                        Section 5.1(a).

         Site:                          The land area shown on the Site Plan
                                        annexed as Exhibit B hereto.

         Substantial Completion Date:   As defined in Section 3.2(c).

         Tax Year:                      As defined in Section 8.1.

         Taxes:                         As defined in Section 8.1.

         Base Taxes:                    The actual Taxes for the Tax Year
                                        commencing on July 1,1999 and ending on
                                        June 30, 2000 (and, to the extent the
                                        Building has not been fully leased when
                                        such actual Taxes are determined,
                                        adjusted as though the Building had been
                                        fully leased at such time), as such may
                                        have been abated pursuant to Section
                                        8.3, if at all, multiplied by 0.95.

         Tax Expenses:                  As defined in Section 8.1.

         Tax Parcel or Properly:        The Building and the land parcel on
                                        which the Building is located.

         Tenant's Proportionate Share:  As defined in Section 9.1.

         Tenant's Removable Property:   As defined in Section 5.2(b).

         Building Standard:             Materials of at least as good quality
                                        (in the parties' reasonable opinion) as
                                        Landlord has elected at the time of
                                        execution of this Lease to use as part
                                        of its standard construction
                                        substantially throughout the Building as
                                        such are more particularly described in
                                        Exhibit J hereto.

         Extension Options:             Consecutive extension option(s)
                                        aggregating up to fifteen (15) years
                                        pursuant to Article 15 hereof.

         Expansion/Right of First

                                      -4-
<PAGE>

         Offer:                         Three expansion options and a right of
                                        first offering as to certain expansion
                                        space in the Building and at 890 Winter
                                        Street, Waltham, Massachusetts pursuant
                                        to Article 17 and Article 18 hereof.

1.3      ENUMERATION OF EXHIBITS. The following Exhibits are a part of this
         Lease, are incorporated herein by reference attached hereto, and are to
         be treated as a part of this Lease for all purposes. Undertakings
         contained in such Exhibits are agreements on the part of Landlord and
         Tenant, as the case may be, to perform the obligations stated therein.

         Exhibit A    -      Floor Plans of Premises
         Exhibit B    -      Site Plan
         Exhibit C    -      Commencement Date Agreement
         Exhibit D    -      Plan Approval Agreement
         Exhibit E    -      Operating Expenses
         Exhibit F    -      Rules and Regulations
         Exhibit G    -      Contractor's Insurance
         Exhibit H    -      Subordination, Non-Disturbance and Attornment
                             Agreement
         Exhibit I    -      Base Building Condition
         Exhibit J    -      Building Standard Materials
         Exhibit K    -      Cleaning Specifications
         Exhibit L    -      Guaranty
         Exhibit M    -      HVAC Specifications
         Exhibit N    -      Signage Locations
         Exhibit 0    -      Competitor List
         Exhibit P    -      Restriction Against Lease Assignment or Space
                             Subletting to be included in Other Tenant Leases

1.4      OTHER DEFINITIONS. The following additional terms, whenever used in
         this Lease (unless the context requires otherwise), shall have the
         respective meanings specified in the Sections of this Lease set forth
         below after such terms;

         Adequate Assurance................................Section 13.1(c)
         Adequate Assurance of Future Performance..........Section 13.1(d)
                  .........................................and Section 13.1(f)
         Affiliate.........................................Section 5.1(c)
         Alterations.......................................Section 5.2(a)
         Amenities.........................................Section 3.1
         ATM...............................................Section 2.2(d)
         Bankruptcy Code...................................Section 13.1(b)
         Base Building Work................................Section 3.2(b)
         Building Average Rate.............................Section 7.5(b)
         Business Hours....................................Section 7.4(a)
         Capital Event.....................................Section 14.17
         Competitor........................................Section 5.1(c)
         Competitor Confirmation Request...................Section 5.1(c)

         Determination Date................................Section 16.1

         Determination Notice..............................Section 15.1
         Essential Services................................Section 7.6
         Estimated Electricity Payment.....................Section 1.2
         Event of Bankruptcy...............................Section 13.1(b)

                                       -5-
<PAGE>

         Extended Term(s)..................................Section 15.1
         Fair Market Rental Value..........................Section 16.1
         First Expansion Space.............................Section 17.1
         First Expansion Space Inclusion Date..............Section 17.1
         First Extended Term...............................Section 15.1
         First Offer Notice................................Section 18.1
         First Offering Space..............................Section 18.1
         First Offering Space Inclusion Date...............Section 18.1
         First Phase.......................................Section 3.2
         First Untaken Space...............................Section 17.2
         Landlord's Work...................................Section 3.2(b)
         Market Capitalization.............................Section 14.17
         Offered Lease Amendment...........................Section 17.12
         Overtime Service..................................Section 7.4(a)
         Plan Submission Date..............................Section 3.2(a)
         Plans.............................................Section 3.2(a)
         Bight of Offering Lease Amendment.................Section 18.6
         Rules and Regulations.............................Section 14.7
         SNDA..............................................Section 14.15
         Second Expansion Space............................Section 17.4
         Second Expansion Space Inclusion Date.............Section 17.4
         Second Extended Term..............................Section 15.1
         Second Untaken Space..............................Section 17.5
         Substantial Completion............................Section 3.2(c)
         Substantially damaged.............................Section 12.2
         Target Date.......................................Section 3.2(b)
         Tax Excess........................................Section 8.2
         Tenant's Delays...................................Section 3.4(c)
         Tenant's First Expansion Notice...................Section 17.1
         Tenant's Second Expansion Notice..................Section 17.4
         Tenant's Third Expansion Notice...................Section 17.7
         Tenant's Offering Notice..........................Section 17.2
         Third Expansion Space.............................Section 17.7
         Third Expansion Space Inclusion Date..............Section 17.7
         Third Untaken Space...............................Section 17.8
         Untaken Space.....................................Section 18.2

                                   ARTICLE 2:
                        PREMISES AND APPURTENANT RIGHTS

2.1      LEASE OF PREMISES. Landlord hereby demises and leases to Tenant, and
         Tenant hereby accepts from Landlord, the Premises (as depicted in the
         floor plan(s) annexed hereto as Exhibit A), for the Lease Term and upon
         and subject to the terms and conditions hereinafter set forth.

2.2      APPURTENANT RIGHTS AND RESERVATIONS. (a) Tenant shall have, as
         appurtenant to the Premises, the non-exclusive right to use, and permit
         its invitees to use in common with others, public or common lobbies,
         hallways, stairways, elevators and the loading platform of the Building
         and common roadways, driveways and walkways necessary for access to the
         Building, and if the portion of the Premises on any floor includes less
         than the entire floor, the common toilets, corridors and elevator lobby
         of such floor; but such rights shall always be subject to reasonable
         rules and regulations from time to time

                                      -6-
<PAGE>

         established by Landlord pursuant to Section 14.7 and to the right of
         Landlord to designate and change from time to time areas and facilities
         so to be used.

         (b)      Excepted and excluded from the Premises are the ceiling,
         floor, perimeter wall and exterior windows (except the inner surface of
         each thereof), and any space in the Premises used for shafts, stacks,
         pipes, conduits, fan rooms, ducts, electric or other utilities, sinks
         or other Building facilities, but the entry doors (and related glass
         and finish work) to the Premises are a part thereof provided that
         Tenant shall have the right to use the vertical penetrations of the
         Building for its piping, conduits, sleeving and cabling with the
         Landlord's prior written consent, such consent not to be unreasonably
         withheld if such use by Tenant will not adversely affect (i) the
         Landlord's utilization of such penetrations for the delivery of
         services required to be provided by Landlord to any tenants of the
         Building or (ii) the structural integrity of the Building]. Landlord
         shall have the right to place in the Premises utility lines, equipment,
         stacks, pipes, conduits, ducts and the like, provided the same do not
         reduce the Premises Rentable Area and are concealed behind any then
         existing walls and/or ceilings of the Premises or are installed in such
         a manner and at such locations so as to reduce to a minimum
         interference with Tenant's use of the Premises. In the event that
         Tenant shall install any hung ceilings or walls in the Premises, Tenant
         shall install and maintain, as Landlord may reasonably require, proper
         access panels .therein to afford access to any facilities above the
         ceiling or within or behind the walls.

         (c)      Tenant shall also have the right (subject to the Rules and
         Regulations from time to time established by Landlord pursuant to
         Section 14.7) to use (i) on an exclusive, reserved basis, 77 parking
         spaces in the basement level of the Building, provided, however, that
         Landlord shall not be obligated to monitor the use of such parking
         spaces or enforce Tenant's exclusive use against unauthorized users
         thereof (except that if Landlord is so requested by Tenant, Landlord
         shall cooperate in all reasonable respects and at Tenant's expense with
         Tenant's efforts to enforce Tenant's exclusive use of such parking
         spaces against unauthorized users thereof), and (ii) on a
         non-exclusive, unreserved basis and in common with use by other tenants
         of the Complex, parking spaces in the parking areas located on the Site
         in an amount, which when aggregated with the parking spaces reserved in
         (i) above, shall equal no more than 3.3 parking spaces per 1,000 square
         feet of Premises Rentable Area. Landlord shall install and maintain, at
         Tenant's expense and with Tenant's reasonable approval, Building
         Standard signage identifying Tenant's reserved parking spaces in the
         basement level of the Building. Landlord acknowledges that Tenant shall
         have the right to monitor the use of Tenant's reserved parking spaces
         in the basement level of the Building and to enforce Tenant's exclusive
         use against unauthorized users thereof. The parking privileges granted
         herein are non-transferable except to an assignee or subtenant
         permitted pursuant to Section 6.1(a). Further, Landlord assumes no
         responsibility whatsoever for loss or damage due to fire, theft or
         otherwise to any automobile(s) parked in the Building or on the Site or
         to any personal property therein, unless attributable to the gross
         negligence or willful misconduct of Landlord, its agents, contractors,
         employees or representatives, and Tenant covenants and agrees, upon
         request from Landlord from time to time, to notify its officers,
         employees, agents and invitees of such limitation of liability. Tenant
         acknowledges and agrees that an appurtenance only is hereby granted,
         and no bailment is intended or shall be created.

         (d)      In the event that an automated teller machine ("ATM") is not
         located at the Complex for general use by all tenants of the Complex,
         Landlord agrees to consider any Tenant proposal to install the same at
         the common areas of the Site or the Complex,

                                      -7-
<PAGE>

         provided that Landlord shall have the right to accept or reject the
         location of such ATM in its sole discretion.

                                    ARTICLE 3
                 LEASE TERM AND BUILDING/PREMISES CONSTRUCTION

3.1      LEASE TERM. The term of this Lease and the estate hereby granted (the
         "Lease Term") shall commence on the first to occur of: '

         (a)      the Substantial Completion Date of the First Phase of the
         Premises, as defined in Section 3.2(c) hereof; and

         (b)      the date upon which Tenant occupies all or any portion of the
First Phase of the Premises for the conduct of its business operations,

         provided that

         (i)      reasonable means of access to the First Phase of the Premises
                  and parking areas on the Site sufficient to provide Tenant
                  with its permitted parking in accordance with Section 2.2(c)
                  hereof shall exist and those facilities reasonably necessary
                  for Tenant's occupancy of the First Phase of the Premises,
                  including, without limitation, an entrance lobby, elevators
                  (which need not consist of all of the elevators in the bank
                  which serves the First Phase of the Premises), toilets,
                  plumbing, water, lighting and electric power facilities shall
                  have been installed and shall be in good operating order and
                  be available to Tenant, but excluding the Amenities (as
                  hereinafter defined); and

         (ii)     the heating, ventilating and air conditioning systems
                  reasonably necessary for Tenant's occupancy of the First Phase
                  of the Premises and the common areas shall have been installed
                  and shall be in good operating order, taking into account the
                  season of the year then in progress, and in accordance with
                  Exhibit M hereto.

         Such date of commencement is hereinafter called the "Commencement
         Date." Promptly upon the occurrence of the Commencement Date, Landlord
         and Tenant shall enter into an agreement, in the form of Exhibit C
         hereto, in which the Commencement Date and specified Lease Term shall
         be stated, but the failure by either party to execute such an agreement
         shall have no effect on the Commencement Date or the duration of the
         Lease Term, as hereinabove determined.

                  Within sixty (60) days after The Commencement Date and at
         Landlord's expense, (i) Landlord covenants to complete the construction
         of and thereafter operate in the Building the following amenities: (a)
         a health and fitness facility with fitness equipment, showers and a
         locker room, and (b) a 1,000 rentable square foot shared-use conference
         facility and (ii) Landlord covenants to complete the construction of a
         food service facility, and thereafter cause a third-party vendor to
         operate the same, at the Building (the "Amenities"). In the event that
         any of the Amenities shall not have been completed within such sixty
         (60) day period (subject to a day for day extension for delays caused
         by Force Majeure), then for each day thereafter Tenant shall not be
         required to pay the daily amount of Basic Rent payable hereunder with
         respect to 10,000 square feet of Premises Rentable Area until such time
         as all of such Amenities shall have been completed.

                                      -8-
<PAGE>

3.2      PREPARATION OF THE PREMISES. (a) Tenant is currently having full
         construction drawings and plans, including mechanical, engineering and
         plumbing drawings (the "Plans") for the layout of its first phase of
         the Premises (the "First Phase") prepared, which Plans shall conform to
         the requirements set forth in part III of Exhibit F and shall
         contemplate the use of the Building Standard materials to be mutually
         determined by Landlord and Tenant, and be submitted to Landlord for its
         approval on or before June 23, 1998 (the "Plan Submission Date"), which
         approval shall not be unreasonably withheld. Failure by Landlord to
         disapprove any submission of the Plans within ten (10) Business Days
         after submission shall constitute approval therefor. Promptly upon
         receipt of any such disapproval containing reasonable detail as to the
         reason(s) therefor, Tenant shall, within five (5) Business Days, revise
         the Plans to address Landlord's reasons for disapproval and resubmit
         the same to Landlord. Landlord shall then have five (5) Business Days
         to approve or disapprove such resubmission, such approval not to be
         unreasonably withheld. Failure by Landlord to disapprove any
         resubmission of the Plans with five (5) Business Days after
         resubmission shall constitute approval therefor. At such time as the
         Plans are completed and approved by Landlord, Landlord and Tenant shall
         sign a letter agreement substantially in the form of Exhibit D,
         identifying the Plans and reciting such approval, and a copy of such
         letter shall be appended to each counterpart of this Lease. On or
         before June 1, 1998, Tenant shall identify in writing to Landlord any
         long-lead time items that Tenant's improvements of the Premises will
         require, but if Tenant fails to do so, the only consequence of such
         failure shall be that, if as a result thereof, Substantial Completion
         with respect to the First Phase of the Premises is delayed beyond
         October 15, 1998, Tenant's failure to have so identified in writing any
         long-lead items by June 1, 1998 shall constitute a Tenant's Delay.

         (b)      Promptly after (i) approval of the Plans, and, if applicable,
         (ii) Tenant's execution of a work letter (if requested by Landlord)
         confirming that the construction cost of Landlord's Work exceeds
         Landlord's Contribution (as defined below), Landlord shall exercise all
         reasonable efforts to obtain the issuance by the City of Waltham of a
         building permit and any other licenses or approvals necessary under
         applicable law for Landlord's Work to commence, and subject to Force
         Majeure and Tenant's Delays, to achieve Substantial Completion of the
         work ("Landlord's Work") specified therein on or before October 15,
         1998, (the "Target Date," as it may be extended pursuant to Section
         3.4). Except as set forth in subsections (d) or (e) below, Tenant shall
         have no claim against Landlord for failure to complete such Work on or
         before the Target Date. Upon completion and approval of the Plans,
         Landlord shall enter into a construction contract with a general
         contractor mutually acceptable to Landlord and Tenant, pursuant to a
         competitive bidding process of the general conditions and fees
         coordinated by Landlord, or, at Tenant's election, Tenant. All
         subcontractor work included in Landlord's Work shall also be bid
         pursuant to a competitive bidding process coordinated by the general
         contractor. Landlord and Tenant shall endeavor in good faith to have
         the general contract and all necessary subcontracts for the First Phase
         of the Building executed and delivered by June 23, 1998. To the extent
         that the contract price set forth in the construction contract exceeds
         an amount ("Landlord's Contribution") equal to $29.50 per square foot
         of Premises Rentable Area then being constructed, Tenant shall be
         liable for such excess costs, such excess costs or portions thereof to
         be paid by Tenant to Landlord on a requisition-by-requisition basis
         throughout the construction process. Tenant shall pay such excess costs
         or any portion thereof to Landlord within fifteen (15) Business Days
         after Landlord's delivery to Tenant of any requisition, accompanied by
         reasonably detailed invoice(s) which have been approved by Landlord's
         Construction Representative, setting forth the amount due from Tenant
         with respect to such invoice(s) (such amount due from Tenant to be
         determined by multiplying the invoiced amount by

                                      -9-
<PAGE>

         a fraction, the numerator of which is the contract price set forth in
         the construction contract minus the amount of Landlord's Contribution
         and the denominator of which is the contract price). Tenant shall, if
         requested by Landlord, execute a work letter confirming such excess
         costs prior to the time Landlord shall be required to commence work. In
         addition, Landlord shall ratably advance funds due under the
         construction contracts for Landlord's Work in direct proportion to the
         square footage amount of Premises Rentable Area then being constructed.
         In the event that the actual cost to Landlord of completing Landlord's
         Work for the First Phase of the Building is less than Landlord's
         Contribution for the First Phase of the Building, then Tenant, to the
         extent Landlord's Contribution for the First Phase of the Building has
         not been funded, shall be entitled to a credit against the next
         succeeding payment(s) of Basic Rent and Additional Charges due by
         Tenant in the amount by which Landlord's Contribution for the First
         Phase of the Building exceeds such cost and Landlord's Contribution for
         the First Phase of the Building shall be deemed fully paid and its
         obligation therefor fully satisfied upon the application of such a
         credit. In addition, if after approval of the Plans, Tenant shall
         request any changes in Landlord's Work, which changes will result in an
         increase in the construction contract price, as a condition to
         Landlord's obligation to agree to such change, Tenant shall pay to
         Landlord any, such increase in the construction contract price, such
         payment to be made within fifteen (15) Business Days after Landlord
         advises Tenant of the amount of such increase. In addition, Tenant
         shall pay to Landlord's Construction Representative a fee in an amount
         equal to $0.295 per square foot of Premises Rentable Area constructed
         as compensation for its construction management and/or supervision
         services, which amount Landlord may elect to offset directly against
         Landlord's Contribution. Costs incurred by Landlord under the
         applicable construction contracts shall be applied and offset directly
         against Landlord's Contribution. The costs of all architectural work
         performed by Landlord or the Agent and the Landlord's costs in
         installing the electric check-meters for the Premises shall also be
         applied to reduce Landlord's Contribution. Landlord's Work does not
         include the work ("Base Building Work") currently being undertaken by
         Landlord, which is identified on Exhibit I hereto and in drawings
         furnished to Tenant's architects, as such drawings may be changed or
         altered by Landlord in the exercise of its reasonable discretion, and
         the cost of performing the Base Building Work shall not be deemed to be
         included in the cost of performing Landlord's Work. If and to the
         extent that Tenant may elect to have Landlord perform Landlord's Work
         in less than all of the Premises such that on the date which is thirty
         (30) months after the Commencement Date, Landlord's Work in any portion
         of the Premises has not been undertaken by Landlord, then, in such
         circumstance, Landlord shall pay to Tenant the amount of Landlord's
         Contribution per square foot of Premises Rentable Area which has not
         been funded by Landlord, by crediting such amount against the next
         succeeding payment(s) of Basic Rent due and payable by Tenant until
         such amount has, by application of such credit, been paid in full to
         Tenant.

         (c)      The First Phase of the Premises shall be deemed substantially
         completed and ready for occupancy on the first day (the "Substantial
         Completion Date") as of which: (i) Landlord's Work with respect to the
         First Phase of the Premises has been completed except for items of work
         (and, if applicable, adjustment of equipment and fixtures) which can be
         completed after occupancy has been taken without causing undue
         interference with Tenant's use of the First Phase of the Premises
         (i.e., so-called "punch list" items); and (ii) a certificate of use and
         occupancy (which may be temporary) has been issued therefor
         ("Substantial Completion"). Landlord shall expeditiously (but in any
         event within 60 days) complete all "punch list" items and Tenant shall
         afford Landlord access to the First Phase of the Premises for such
         purposes. Tenant acknowledges that, given the scope of Landlord's Work,
         it is possible that certain portions of the Building may be

                                      -10-
<PAGE>

         substantially completed before Substantial Completion of all of
         Landlord's Work with respect to the First Phase of the Premises. If (i)
         Tenant shall desire to occupy a portion of the First Phase of the
         Premises prior to Substantial Completion of all of Landlord's Work with
         respect to the First Phase of the Premises, and (ii) Landlord, in its
         reasonable discretion, determines that partial occupancy by Tenant of
         such portions of the Building as shall have been substantially complete
         will not interfere with or delay the remainder of Landlord's Work,
         Landlord may give Tenant notice thereof and, subject to Section 3.1,
         Tenant may occupy that portion of the First Phase of the Premises which
         is substantially completed, and all payments of Basic Rent, Additional
         Charges and the like shall be prorated according to the amount of space
         so occupied by Tenant.

         (d)      If the Substantial Completion Date has not occurred on or
         before the thirtieth (30th) day after the Target Date, subject to a
         day-for-day extension due to each day of delay attributable to Tenant's
         Delay(s) and/or Force Majeure, then for each day after such 30th day
         that Substantial Completion is not achieved, Tenant shall not be
         required to pay Basic Rent or Additional Charges for one (1) day after
         the Commencement Date. Further, if the Substantial Completion Date has
         not occurred on or before the sixtieth (60th) day after the Target Date
         subject to a day-for-day extension due to each day of delay
         attributable to Tenant's Delay(s) and/or Force Majeure, then for each
         day after such 60th day that Substantial Completion is not achieved,
         Tenant shall not be required to pay Basic Rent or Additional Charges
         for one and one-half (1 1/2) days after the Commencement Date. Landlord
         shall endeavor to provide Tenant with access to the Premises, on a
         non-exclusive basis and in common with Landlord's Work, on or before
         fifteen (15) days prior to the Commencement Date for Tenant's
         furniture, fixture and equipment installation at the Premises, but
         Landlord shall have no liability to Tenant if such access is not in
         fact provided by such date.

         (e)      If the Substantial Completion Date has not occurred on or
         before the one-hundred eightieth (180th) day after the Target Date,
         subject to a day-for-day extension due to each day of delay
         attributable to Tenant's Delay(s) and/or Force Majeure, Tenant may
         elect to terminate this Lease by giving notice to Landlord, not later
         than thirty (30) days after such date of its desire to so terminate,
         and this Lease shall cease and come to an end without further liability
         or obligation on the part of either party upon the delivery of such
         notice.

3.3      QUALITY AND PERFORMANCE OF WORK/CONCLUSIVENESS OF LANDLORD'S
         PERFORMANCE. All construction work required or permitted by this Lease
         shall be done in a good and workmanlike manner with Building Standard
         materials except as otherwise agreed to by Landlord and Tenant, or, if
         not applicable, new, first-class materials, in a lien-free manner and
         in compliance with all applicable laws and requirements of public
         authorities and insurance bodies related to, or arising out of the
         performance of, such construction work. Each party may inspect the work
         of the other at reasonable times, and the Construction Representative
         of each party shall promptly give notice of any approvals and other
         actions on the party's behalf required to be given in connection with
         design and construction. Except to the extent to which Tenant shall
         have given Landlord notice, not later than the end of the sixth full
         calendar month following the Commencement Date, of specific respects in
         which Landlord has not performed Landlord's Work or Base Building Work,
         Tenant shall be deemed conclusively to have approved all such work and
         shall have no claim that Landlord has failed to perform or has
         improperly performed any of Landlord's Work or Base Building Work.
         Except for Landlord's Work and the Base Building Work, and except as
         expressly provided herein, the Premises are being leased in their
         condition AS IS WITHOUT REPRESENTATION OR WARRANTY by Landlord, except
         for latent defects in such

                                      -11-
<PAGE>

         work. Notwithstanding the foregoing, Landlord hereby represents and
         warrants to Tenant that: (i) Landlord's Work and the Base Building Work
         will be undertaken in accordance with all applicable laws, codes and
         ordinances, including without limitation the Americans With
         Disabilities Act of 1990 and requirements of public authorities and
         insurance bodies related to, or arising out of the performance of, such
         construction work, (ii) Landlord has not received from any governmental
         agency having jurisdiction any written notice to the effect that the
         Premises are in violation of any applicable law, code or ordinance,
         which violation remains outstanding as of the date hereof, (iii) on the
         Commencement Date, no hazardous substances, hazardous materials, PCB's
         or friable and accessible asbestos containing materials will be present
         in the Premises, Building or Complex which would require remediation
         under applicable law and (iv) on the Commencement Date, the Base
         Building Work and the Landlord's Work will comply with the Americans
         With Disabilities Act of 1990 to the extent required by law. To the
         extent that Tenant will be responsible for maintenance and/or repair of
         any item of work included in Landlord's Work or the Base Building Work,
         then Landlord shall use reasonable efforts to obtain from Landlord's
         contractor a warranty for the benefit of Tenant covering such items.

3.4      TENANT'S DELAYS. (a) To the extent a delay shall occur in the
         Substantial Completion Date as the result of:

         (i)      any written request by Tenant that Landlord delay the
         commencement or completion of Landlord's Work for any reason except for
         delays requested by Tenant due solely to the failure of Landlord's Work
         to comply with the provisions of Section 3.3;

(ii)     failure by Tenant to (v) submit promptly the Plans within the time
         period set forth in Section 3.2(a) and revise the same to satisfy
         Landlord's reasonable objections within the time periods set forth
         above, or (w) identify in writing to Landlord by June 1, 1998 any
         long-lead items that Tenant's improvements of the Premises will
         require, or (x) enter into a work letter in form and substance
         reasonably satisfactory to Tenant if so requested by Landlord, or (y)
         pay to Landlord any excess costs attributable to Landlord's Work in
         accordance with the provisions of Section 3.2(b) hereof, or (z) any
         change by Tenant in any of the Plans after approval or deemed approval
         thereof by Landlord;

         (iii)    any other act or omission of Tenant or its officers, agents,
         servants or contractors;

         (iv)     any long-lead time items, any change orders to the Plans which
         are not in accordance with Building Standards, or lack of timely action
         by Tenant with respect to the submission of information which Tenant is
         required to provide; or

         (v)      any displacement of any of Landlord's Work from its place in
         Landlord's construction schedule resulting from any of the causes for
         delay referred to in clauses (i), (ii), (iii) or (iv) of this paragraph
         and the fitting of such Landlord's Work back into such schedule;

         and, as a result of such delay, Substantial Completion with respect to
         the First Phase of the Premises does not occur before October 15, 1998,
         then Tenant shall, commencing on October 15, 1998, pay to Landlord for
         each day of such delay the amount of Basic Rent and Additional Charges
         that would have been payable hereunder had the Tenant's obligation to
         pay Basic Rent commenced on October 15, 1998. Tenant shall reimburse
         Landlord for all additional costs reasonably incurred by Landlord in
         connection with the completion of the Landlord's Work by reason of such
         Tenant's Delay. Landlord shall

                                      -12-
<PAGE>

         provide Tenant with written notice of the occurrence of any delay
         within ten (10) Business Days after Landlord becomes aware of the event
         giving rise to such delay.

         (b)      If a delay in the Substantial Completion Date, or if any
         portion of such delay, is the result of Force Majeure, and such delay
         would not have occurred but for a delay described in paragraph (a),
         such delay shall be deemed added to the delay described in that
         paragraph.

         (c)      The delays referred to in paragraphs (a) and (b) are herein
         referred to collectively and individually as "Tenant's Delay."

         (d)      The Target Date shall automatically be extended for the period
         of any delays caused by Tenant's Delay(s) or Force Majeure.

3.5      TENANT ENTRY FOR FURNISHING. Prior to the Commencement Date Landlord
         shall permit Tenant to enter the Premises for the purpose of performing
         any work to be performed by Tenant or Alterations (as hereafter
         defined), when in Landlord's reasonable judgment the same can be done
         without any undue interference with Landlord's performance of the
         remaining work it is obligated to perform under this Article 3. Any
         such entry shall be at Tenant's sole risk and Landlord shall not be
         responsible for any damage or loss to property or installations placed
         in the Premises by Tenant prior to the Commencement Date. In addition,
         in no event shall Tenant make use of any labor in the Building or
         otherwise suffer or permit any action to be taken which would result in
         labor difficulties or otherwise delay the performance by Landlord of
         such remaining work. Prior to performing any Alterations or other
         Tenant work, Tenant shall provide Landlord with proof of insurance in
         accordance with the Rules and Regulations.

3.6      MULTIPLE CONSTRUCTION PHASES. It is anticipated that Landlord's Work
         will consist of multiple phases. The Commencement Date for the entire
         Premises is triggered by either Substantial Completion or occupancy of
         the First Phase of the Premises as provided in Section 3.1. The terms
         and provisions of Sections 3.2, 3.3, 3.4 and 3.5 (including Landlord's
         Contribution) hereof shall apply to each phase of Landlord's Work
         subsequent to the First Phase as though the applicable phase was
         substituted in lieu of the "First Phase" of the Premises. For purposes
         of Section 3.2, the Tenant shall prepare the Plans for each phase of
         the Premises subsequent to the First Phase and submit the same to
         Landlord for its approval on such dates as Tenant shall elect, and
         Tenant shall identify to Landlord in writing at such time any long lead
         time items that Tenant's improvements of the Premises applicable to
         such phase will require. The Target Date for each phase after the First
         Phase shall be the date which is ten (10) weeks after (i) approval of
         the Plans for such phase; (ii) issuance by the City of Waltham of a
         building permit and any other licenses or approvals necessary under
         applicable law for Landlord's Work with respect to such phase to
         commence and, if applicable, (iii) Tenant's execution of a work letter
         (if requested by Landlord) confirming that the construction costs of
         Landlord's Work exceeds Landlord's Contribution, subject to Force
         Majeure and Tenant's Delays, provided that Landlord agrees to utilize
         reasonable efforts to complete such phase of Landlord's Work as
         promptly as practicable under the circumstances. As to phases
         subsequent to the First Phase, the rent abatement and termination
         provisions set forth in Section 3.2(d) and (e) shall apply only to the
         applicable phase then being constructed and shall not be deemed to
         provide a rent abatement or termination right to the Tenant as to any
         prior phase of the Premises.

                                      -13-
<PAGE>

                                    ARTICLE 4
                                   BASIC RENT

4.1      PAYMENT. (a) Tenant agrees to pay to Landlord, or as directed by
         Landlord, commencing on the Commencement Date without offset, abatement
         (except as provided in Sections 7.6 and 12.1), deduction or demand, the
         Basic Rent. Such Basic Rent shall be payable in equal monthly
         installments, in advance, on the first day of each and every calendar
         month during the Lease Term, at Landlord's Original Address, or at such
         other place as Landlord shall from time to time designate by notice, in
         lawful money of the United States. In the event that any installment of
         Basic Rent or such of the Additional Charges as are payable on account
         of Taxes, Operating Expenses or Estimated Electricity Payment are not
         paid within five (5) Business Days of the date due, Tenant shall pay to
         Landlord, in addition to any charges under Section 14.18, an
         administrative fee equal to (i) one percent (1%) of the overdue
         payment, if such failure to pay shall occur for the second time within
         any calendar year, and (ii) three percent (3%) of the overdue payment,
         if such failure to pay shall occur more than twice within any calendar
         year. Landlord and Tenant agree that all amounts due from Tenant under
         or in respect of this Lease, whether labeled Basic Rent, Additional
         Charges or otherwise, shall be considered as rental reserved under this
         Lease for all purposes, including without limitation regulations
         promulgated pursuant to the Bankruptcy Code, and including further
         without limitation, Section 502(b) thereof.

         (b)      Basic Rent for any partial month shall be pro-rated on a daily
         basis, and if the first day on which Tenant must pay Basic Rent shall
         be other than the first day of a calendar month, the first payment
         which Tenant shall make to Landlord shall be equal to a proportionate
         part of the monthly installment of Basic Rent for the partial month
         from the first day on which Tenant must pay Basic Rent to the last day
         of the month in which such day occurs, plus the installment of Basic
         Rent for the succeeding calendar month.

4.2      RENT CREDITS. Tenant shall be entitled to credits against Basic Rent:
         (i) equal to the amount of Basic Rent payable hereunder with respect to
         60,000 square feet of Premises Rentable Area from the Commencement Date
         until the date four (4) months after the Commencement Date, and (ii)
         equal to the amount of Basic Rent payable hereunder with respect to
         15,584 square feet of Premises Rentable Area from the Commencement Date
         until the date two (2) years after the Commencement Date, provided that
         on the date of application of each monthly installment of the rent
         credits, Tenant shall not be in Default of any monetary obligation
         hereunder beyond any applicable cure and/or notice period.

                                    ARTICLE 5
                                 USE OF PREMISES

5.1      PERMITTED USE. (a) Tenant agrees that the Premises shall be used and
         occupied by Tenant only for Permitted Uses specifically excluding,
         without limitation, use for utility company or employment agency
         offices (other than corporate, executive or legal staff offices) or use
         for medical or dental offices (other than administrative offices) or
         governmental offices. Tenant's Permitted Uses shall include the right
         to install and use an ATM in the Premises and to use and occupy
         portions of the Premises as a fitness area (with related shower, sauna
         and locker room facilities) for use by Tenant's employees and business
         invitees; however, Tenant agrees that such fitness area and related
         facilities shall not be available for general public use. Tenant's
         Permitted Uses shall also include the right to use and occupy portions
         of the Premises as a private bathroom

                                      -14-
<PAGE>

         area and/or as computer facilities ancillary to its executive and
         general office use. Tenant may use and occupy portions of the Premises
         as dining areas (including kitchen, cafeteria and private dining areas)
         for use by Tenant's employees and business invitees; however, Tenant
         agrees that it shall not use the Premises or any part thereof, or
         permit the Premises or any part thereof, to be used for the preparation
         or dispensing of food or beverages for general public use or
         consumption. Tenant shall not use, or suffer or permit the use of, or
         suffer or permit anything to be done in or anything to be brought into
         or kept in or about the Premises or the Building or any part thereof
         (a) which would violate any of the provisions of this Lease, (b) for
         any unlawful purposes or in any unlawful manner, (c) which is not
         normally found in first-class office buildings in the greater Boston
         area or (d) which, in the reasonable judgment of Landlord, shall in any
         way (i) impair or tend to impair the appearance or reputation of the
         Building or the Complex or (ii) impair or interfere with or tend to
         impair or interfere with any of the Building services or the proper and
         economic heating, ventilation, cleaning, air conditioning or other
         servicing of the Building or Premises, or with the use of any of the
         other areas of the Building, or occasion discomfort, inconvenience or
         annoyance to, any of the other tenants or occupants of the Building or
         the Complex. Tenant shall have the right to utilize the common areas of
         the Site for occasional company picnics and similar events subject to
         all applicable law and reasonable time, place and manner restrictions
         imposed by Landlord and provided that such use shall not unreasonably
         interfere with, or otherwise violate, the rights of other tenants at
         the Building under such other tenants' leases.

         (b)      Tenant agrees to conform to the following provisions during
         the Lease Term:

                  (i)      Tenant shall cause all freight to be delivered to or
                  removed from the Building and the Premises in accordance with
                  reasonable rules and regulations established by Landlord
                  therefor;

                  (ii)     Tenant shall not perform any act or carry on any
                  practice which may injure the Premises, or any other part of
                  the Building, or cause any offensive odors or loud noise or
                  constitute a nuisance or a menace to any other tenant or
                  tenants or other persons in the Building;

                  (iii)    Tenant shall, in its use of the Premises, comply with
                  the requirements of all applicable governmental laws, rules
                  and regulations applicable to the Premises, including without
                  limitation the accessibility provisions of the Americans With
                  Disabilities Act of 1990.

         (c)      Landlord agrees that it will not (a) enter into a lease of any
         space in the Complex to any of the entities (individually, a
         "Competitor") listed in Exhibit O hereto, or (b) enter into a lease of
         any space in the Complex without including a provision in form and
         content substantially similar to the restriction contained in Exhibit P
         attached hereto which expressly restricts any tenant (other than Tenant
         and any of its Affiliates as Tenant under this Lease) from any such
         assignment of lease or subletting to a Competitor without first
         offering the space proposed to be sublet or the lease to be assigned to
         Tenant in accordance with the right of first offer set forth in Exhibit
         P hereto. Landlord agrees to furnish the list of Competitors set forth
         in Exhibit O hereto, or.such other Competitor list then in effect
         following a Competitor Confirmation Request (hereinafter defined) made
         by Landlord, to each such tenant whose lease contains a comparable
         provision restricting assignment or subletting based upon the list of
         Competitors set forth in Exhibit O or any modified list of Competitors
         resulting from a Competitor Confirmation Request submitted by Landlord
         to Tenant. Landlord agrees to

                                      -15-
<PAGE>

         cooperate in all reasonable respects, at the sole cost of Tenant, with
         Tenant in the enforcement of such restriction contained in any tenant
         lease, provided that Tenant's sole remedy against such tenant shall be
         limited to injunctive relief. In no event, and under no circumstance,
         shall Landlord be obligated to enforce such restriction against tenants
         of the Complex whose lease contains the restriction set forth in
         Exhibit P hereto or a comparable restriction, and in no event, and
         under no circumstance, shall Landlord incur any liability to Tenant for
         any such tenant's violation of such restriction, or for any claim or
         legal action instituted by Tenant against Landlord alleging Landlord's
         failure to use reasonable commercial efforts to enforce the provisions
         of this Section against the tenant under any such lease which contains
         such restriction or a similar restriction. Anything expressly or
         impliedly contained in this Section 5.1(c) to the contrary
         notwithstanding, none of the preceding provisions will ever be
         interpreted or construed as a restriction on Landlord, its successors
         and assigns, from granting its consent to the subletting of space under
         or assignment of any lease existing on the date hereof where no
         restriction substantially similar to the restriction contained in
         Exhibit P hereto has been included in any such pre-existing lease.
         Moreover, the foregoing restriction shall not apply (i) to Landlord,
         its successors and assigns, granting its consent to the subletting of
         space under or assignment of any tenant lease containing the
         restriction set forth in Exhibit P hereto or similar restriction if
         Landlord has determined to its reasonable satisfaction that such tenant
         has initially complied with the right of first offer provisions set
         forth in Exhibit P hereto, which determination made by Landlord shall
         be conclusive and binding upon Tenant in the absence of Landlord's bad
         faith; (ii) if Tenant or its Affiliates are not in actual occupancy of
         at least 75% of the Premises Rentable Area; (iii) to Affiliates of a
         Competitor; (iv) to a Competitor if, after a merger or consolidation by
         a Competitor with another entity, or a sale, lease, license or other
         disposition by a Competitor of all or substantially all of its assets
         to another entity, whether in one transaction or a series of
         transactions, such Competitor is not the surviving entity; or (v) if,
         after a merger or consolidation by the Guarantor with another entity,
         or a sale, lease, license or other disposition by the Guarantor of all
         or substantially all of its assets to another entity, whether in one
         transaction or a series of transactions, the Guarantor is not the
         surviving entity.

         For so long as the restriction prohibiting Landlord from leasing space
         in the Complex to a Competitor listed in Exhibit O is in force and
         applicable, Landlord shall have the right, at any time and from time to
         time during the Lease Term, to request in writing of Tenant a
         determination as to whether, in the reasonably exercised good faith
         judgment of Tenant, the business of any Competitor listed in Exhibit O
         hereto remains competitive with the business then being conducted by
         Tenant or its Affiliates in the Premises (a "Competitor Confirmation
         Request"). Within ten (10) Business Days after receipt of Landlord's
         Competitor Confirmation Request, Tenant shall notify Landlord of its
         determination, which determination shall be binding upon Landlord and
         Tenant, absent manifest error. Tenant's failure to respond to any
         Competitor Confirmation Request (if the same shall continue for an
         additional five (5) Business Days after receipt of a second notice of a
         Competitor Confirmation Request, which second notice shall state that
         Tenant has failed to respond within the period required under this
         Section 5.1(c) and continued failure to respond shall be deemed a
         Tenant determination that such Competitor(s) is no longer operating a
         competing business) shall constitute Tenant's affirmation,
         acknowledgement and consent that, for the balance of the Lease Term,
         the leasing restriction set forth in this Section 5.l(c) shall not
         apply to the Competitor(s) for which such Competitor Confirmation
         Request was submitted by Landlord to Tenant.

         For the purposes of this Section 5.1(c), "Affiliate" means (i) any
         entity directly or indirectly controlling, controlled by or under
         common control with such entity; (ii) any

                                      -16-
<PAGE>

         entity owning or controlling ten percent (10%) or more of the
         outstanding voting interests of such entity; or (iii) any entity of
         which such entity owns or controls ten percent (10%) or more of the
         voting interests.

5.2      INSTALLATIONS AND ALTERATIONS BY TENANT. (a) Tenant shall make no
         alterations, additions (excluding for the purposes hereof interior
         painting and wall-to-wall carpeting which may be performed or installed
         without Landlord's prior written consent), improvements or
         refurbishments (collectively, "Alterations") in or to the Premises
         (including any improvements other than Landlord's Work necessary for
         Tenant's initial occupancy of the Premises) without Landlord's prior
         written consent, which consent shall not be unreasonably withheld with
         respect to non-structural Alterations that do not affect the Building's
         electrical, plumbing or mechanical systems. Any such Alterations shall
         be in accordance with complete plans and specifications meeting the
         requirements set forth in the Rules and Regulations from time to time
         in effect and approved in advance by Landlord. Such work shall (i) be
         performed in a good and workmanlike manner by contractors approved
         reasonably by Landlord and in compliance with all applicable laws, (ii)
         be made at Tenant's sole cost and expense and at such times and in such
         a manner as Landlord may from time to time reasonably designate, (iii)
         be made only in accordance with the Rules and Regulations from time to
         time in effect with respect thereto, and (iv) as to any fixtures other
         than Tenant's Removable Property become part of the Premises and the
         property of Landlord upon the expiration of the Lease Term. If any
         Alterations shall involve the removal of fixtures, equipment or other
         property in the Premises which are not Tenant's Removable Property,
         such fixtures, equipment or property shall be promptly replaced by
         Tenant at its expense with new fixtures, equipment or property of like
         utility and of at least equal quality.

         (b)      All articles of personal property and all business fixtures,
         machinery and equipment and furniture owned or installed by Tenant
         ("Tenant's Removable Property") solely at its expense (or by Landlord's
         Contribution) in the Premises including raised flooring, any suspended
         or wall mounted lighting fixtures, millwork, glass partitioning,
         mounted furniture, countertops, video or computer screens shall remain
         the property of Tenant and may be removed by Tenant at or prior to the
         expiration of this Lease, provided that Tenant, at its expense, shall
         repair any damage to the Building caused by such removal.

         (c)      Notice is hereby given that Landlord shall not be liable for
         any labor or materials furnished or to be furnished to Tenant upon
         credit, and that no mechanic's or other lien for any such labor or
         materials shall attach to or affect the reversion or other estate or
         interest of Landlord in and to the Premises. To the maximum extent
         permitted by law, before such time as any contractor commences to
         perform work on behalf of Tenant, such contractor (and any
         subcontractors) shall furnish a written statement acknowledging the
         provisions set forth in the prior clause. Whenever and as often as any
         mechanic's lien shall have been filed against the Building or all or
         any part of the Site based upon, any act or interest of Tenant or of
         anyone claiming through Tenant, Tenant shall forthwith take such action
         by bonding, deposit or payment as will remove or satisfy the lien.

         (d)      In the course of any work being performed by Tenant (including
         without limitation the "field installation" of any Tenant's Removable
         Property), Tenant agrees to use labor compatible with that being
         employed by landlords for work in or to the Building or other buildings
         in the Complex and not to employ or permit the use of any labor or
         otherwise take any action which might result in a labor dispute
         involving

                                      -17-
<PAGE>

         personnel providing services in the Building pursuant to arrangements
         made by Landlord.

                                    ARTICLE 6
                           ASSIGNMENT AND SUBLETTING

6.1      PROHIBITION. (a) Except as expressly permitted in this Article 6,
         Tenant covenants and agrees that, whether voluntarily, involuntarily,
         by operation of law or otherwise, neither this Lease nor the Lease Term
         and estate hereby granted, nor any interest herein or therein, will be
         assigned, mortgaged, pledged, encumbered or otherwise transferred, and
         that neither the Premises nor any part thereof will be encumbered in
         any manner by reason of any act or omission on the part of Tenant, or
         used or occupied or permitted to be used or occupied by anyone other
         than Tenant or any successor entity permitted by Section 6.1(b), or for
         any use or purpose other than a Permitted Use, or be sublet (which
         term, without limitation, shall include granting of concessions,
         licenses and the like) in whole or in part, or be offered or advertised
         for assignment or subletting. Without limiting the foregoing, any
         agreement pursuant to which: (y) Tenant is relieved from the obligation
         to pay, or a third party agrees to pay on Tenant's behalf, all or any
         portion of Basic Rent or Additional Charges due under this Lease;
         and/or (z) a third party undertakes or is granted the right to assign
         or attempt to assign this Lease or sublet or attempt to sublet all or
         any portion of the Premises shall for all purposes hereof be deemed to
         be an assignment of this Lease and subject to the provisions of this
         Article 6.

         (b)      Anything in Section 6.1(a) to the contrary notwithstanding,
         transactions with an entity (i) into or with which Tenant is merged or
         consolidated, (ii) to which all or substantially all of Tenant's assets
         are transferred as a going concern, or (iii) which controls or is
         controlled by Tenant or is under common control with Tenant, shall not
         be deemed to be an assignment or subletting within the meaning of this
         Article 6, provided that in any of such events:

                  (i)      in the reasonable judgment of Landlord, the successor
                  to Tenant is of a reputation that would not have a material
                  adverse effect on the management or marketing of the Building,

                  (ii)     the assignee or subtenant agrees directly with
                  Landlord, by written instrument in form satisfactory to
                  Landlord, to be bound by all the obligations of Tenant
                  hereunder including, without limitation, the covenant against
                  further assignment and subletting,

                  (iii)    in no event shall Tenant or Guarantor be released
                  from their respective obligations under this Lease and the
                  guaranty thereof, and

                  (iv)     any such transfer or transaction is for a legitimate,
                  regular business purpose of Tenant other than a transfer of
                  Tenant's interest in this Lease.

         (c)      If, in violation of this Article 6, this Lease be assigned, or
         if the Premises or any part thereof be sublet or occupied by anyone
         other than Tenant, except as permitted by Section 6.1(b) Landlord may,
         at any time and from time to time, collect rent and other charges from
         the assignee, subtenant or occupant, and apply the net amount collected
         to the rent and other charges herein reserved, but no such assignment,
         subletting, occupancy, collection or modification of any provisions of
         this Lease shall be deemed a

                                      -18-
<PAGE>

         waiver of this covenant, or the acceptance of the assignee, subtenant
         or occupant as a tenant, or a release of Tenant from the further
         performance by Tenant of all the terms, conditions and covenants on the
         part of Tenant to be performed hereunder. Any consent by Landlord to a
         particular subletting or occupancy shall not in any way diminish the
         prohibition stated in paragraph (a) of this Section 6.1 or the
         continuing liability of the original named Tenant. No assignment shall
         be binding on Landlord unless such assignee or Tenant shall deliver to
         Landlord a duplicate original of the instrument of assignment which
         contains a covenant of assumption by the assignee of all of the
         obligations aforesaid and shall obtain from Landlord the aforesaid
         written consent prior thereto unless such transfer is otherwise
         permitted by Section 6,l(b). No assignment or subletting hereunder
         shall relieve Tenant or Guarantor from their respective obligations
         hereunder and under the guaranty hereof and Tenant shall remain fully
         and primarily liable therefor. No such assignment, subletting, or
         occupancy shall affect or be contrary to Permitted Uses. Any consent by
         Landlord to a particular assignment, subletting or occupancy shall be
         revocable, and any assignment, subletting or occupancy shall be void ab
         initio if the same shall fail to require that such assignee, subtenant
         or occupant agree therein to be independently bound by and upon all of
         the covenants, agreements, terms, provisions and conditions set forth
         in this Lease on the part of Tenant to be kept and performed.

6.2      CONSENT TO SUBLEASE. (a) Notwithstanding the prohibition set forth in
         Section 6.1(a), Landlord shall not unreasonably withhold its consent to
         one or more subletting requested by Tenant, provided that:

         (i)      The business of each proposed subtenant and its use of the
         Premises shall be consistent with the Permitted Uses, including the
         specific exclusions therefrom set forth in Section 5.1 hereof;

         (ii)     In the reasonable judgment of Landlord the proposed subtenant
         is of a reputation that would not have a material adverse effect on the
         management or marketing of the Building;

         (iii)    Neither the proposed subtenant, nor any person or entity who
         directly or indirectly controls, is controlled by, or is under common
         control with, the proposed subtenant or any person who controls the
         proposed subtenant, shall be a government (or subdivision or agency
         thereof);

         (iv)     The form of the proposed sublease shall be reasonably
         satisfactory to Landlord and shall comply with the applicable
         provisions of this Article 6;

         (v)      Not later than thirty (30) days prior to the proposed
         commencement of such sublease, Landlord shall have received information
         reasonably sufficient to determine compliance with the foregoing
         conditions; and

         (vi)     Unless and until the second anniversary of the Commencement
         Date shall have occurred, (a) the proposed space to be sublet, when
         aggregated with the space sublet pursuant to all other subleases of the
         Premises, including those permitted under Section 6.2(b), shall not
         exceed 65,000 square feet of Premises Rentable Area and (b) any
         proposed sublease (including any extensions thereof which are
         unilaterally exercisable by the subtenant) shall expire prior to the
         sixth anniversary of the Commencement Date.

                                      -19-
<PAGE>

         Moreover, notwithstanding such sublease, Tenant and Guarantor shall in
         all cases remain fully and primarily liable hereunder and under the
         guaranty hereof.

         (b)  Notwithstanding the prohibitions set forth in Section 6.1(a) or
         Section 6.2(a), Tenant shall have the right, without the prior consent
         of Landlord, to sublet all or a portion of the Premises to any entity
         which controls or is controlled by or is under common control with
         Tenant (or to any accounting or consulting firm or vendor which
         provides substantial business services to Tenant and such sublease
         would significantly enhance the provision of such services to Tenant),
         provided that:

         (i)      The business of each proposed subtenant and its use of the
         Premises shall be consistent with the Permitted Uses, including the
         specific exclusions therefrom set forth in Section 5.1 hereof;

         (ii)     The form of the proposed sublease shall be reasonably
         satisfactory to Landlord and shall comply with the applicable
         provisions of this Article 6; and

         (iii)    In no event shall Tenant or Guarantor be released from their
         respective obligations under this Lease and the guaranty thereof.

6.3      EXCESS PAYMENTS. In the event that Tenant shall enter into one or more
         subleases pursuant to Section 6.2, if the rent and other sums paid to
         Tenant on account of any such sublease exceed the Basic Rent and
         Additional Charges allocable to that portion of the Premises subject to
         such sublease, plus actual out-of-pocket third party expenses
         reasonably incurred in connection with such sublease (such expenses to
         be prorated evenly over the term of such sublease), including without
         limitation reasonable brokerage commissions actually paid to a licensed
         broker, Tenant shall pay to Landlord, as an Additional Charge, 50% of
         such excess, such amount to be paid monthly with payments by Tenant of
         Basic Rent hereunder.

6.4      TERMINATION. Notwithstanding any other provision of this Article 6 to
         the contrary, if and at each such time as Tenant shall intend to enter
         into any sublease (other than a sublease permitted by Section 6.2(b) or
         Section 6.2(a)(vi)), which when aggregated with all other subleases
         (other than those permitted by Section 6.2(b) or Section 6.2(a)(vi))
         covers at least twenty-five percent (25%) of the Premises Rentable
         Area, and is for a term which is substantially the remainder of the
         Lease Term, then Tenant shall give Landlord notice of such intent not
         earlier than ninety (90), and not later than thirty-five (35), days
         prior to the effective date of such proposed sublease, and Landlord may
         then approve or disapprove of the proposed sublease or elect to
         terminate this Lease (if less than all or substantially all of the
         Premises are covered by such sublease, then such termination shall
         affect only that portion of the Premises proposed to be covered by such
         sublease) by giving notice to Tenant of such approval, disapproval or
         election to terminate not later than thirty (30) days after receipt of
         Tenant's notice and, upon the giving of such notice by Landlord, this
         Lease shall terminate with respect to such portion sixty (60) days
         after the giving of such notice by Landlord with the same force and
         effect as if such date were the date originally set forth herein as the
         expiration date hereof. If Landlord shall elect to terminate this Lease
         with respect to any portion of the Premises as hereinabove provided,
         then from and after the effective date of such termination, the
         definitions of Basic Rent, Premises Rentable Area, Tenant's
         Proportionate Share and the number of exclusive parking spaces in the
         basement level of the Building shall be adjusted to reflect that
         portion of the Premises that remains subject to this Lease after such
         termination. In no event shall Tenant be required to

                                      -20-
<PAGE>

         relinquish more exclusive parking spaces than would have been allotted
         to such subtenant under the proposed sublease.

6.5      MISCELLANEOUS. (a) Any sublease consented to by Landlord or permitted
         hereunder shall be expressly subject and subordinate to all of the
         covenants, agreements, terms, provisions and conditions contained in
         this Lease. Any proposed sub-sublease or proposed assignment of a
         sublease shall be subject to the provisions of this Article 6. Tenant
         shall reimburse Landlord on demand, as an Additional Charge, for any
         costs (including reasonable attorneys' fees and expenses) incurred by
         Landlord in connection with any actual or proposed assignment or
         sublease, whether or not consummated, including the reasonable costs of
         making investigations as to the acceptability of the proposed assignee
         or subtenant. Any sublease to which Landlord is required to consent and
         gives its consent shall not be valid or binding on Landlord unless and
         until Tenant and the sublessee execute a consent agreement in form and
         substance reasonably satisfactory to Landlord.

         (b)      Notwithstanding any sublease, or any amendments or
         modifications subsequent thereto, Tenant will remain fully liable for
         the payment of Basic Rent, Additional Charges and other charges and for
         the performance of all other obligations of Tenant contained in this
         Lease. Any act or omission of any subtenant, or of anyone claiming
         under or through any subtenant, that violates any of the obligations of
         this Lease shall be deemed a violation of this Lease by Tenant.

         (c)      The consent by Landlord to any sublease shall not relieve
         Tenant or any person claiming through or under Tenant of the
         obligations to obtain the consent of Landlord, pursuant to the
         provisions of this Article 6, to any subsequent sublease.

         (d)      With respect to each and every sublease authorized by Landlord
         under the provisions of this Article 6, it is further agreed that any
         such sublease shall provide that: (i) no sublease shall be valid, and
         no subtenant shall take possession of all or any part of the Premises
         until a fully executed counterpart of such sublease has been delivered
         to Landlord; (ii) each sublease shall provide that it is subject and
         subordinate to this Lease; (iii) Landlord may enforce the provisions of
         the sublease, including collection of rents; and (iv) in the event of
         termination of this Lease or reentry or repossession of the Premises by
         Landlord, Landlord may, at its option, take over all of the right,
         title and interest of Tenant, as sublessor, under such sublease, and
         such subtenant shall, at Landlord's option, attorn to Landlord but
         nevertheless Landlord shall not (A) be liable for any previous act or
         omission of Tenant under such sublease; (B) be subject to any defense
         or offset previously accrued in favor of the subtenant against Tenant;
         or (C) be bound by any previous modification of such sublease made
         without Landlord's written consent or by any previous prepayment of
         more than one month's rent.

         (e)      If Landlord shall rightfully fail or refuse to give its
         consent to any proposed assignment or sublease in accordance with its
         rights in this Article 6, Tenant shall indemnify and hold harmless
         Landlord from and against any and all loss, liability, costs and
         expenses (including, without limitation, reasonable attorneys' fees)
         asserted against, imposed upon or incurred by Landlord by reason of any
         claims made against Landlord by the proposed assignee or sublessee or
         by any brokers, finders or other persons for commissions or other
         compensation in connection with the proposed assignment or sublease.

         (f)      If Landlord grants its consent to an assignment or sublease
         and such assignment or sublease does not become effective for any
         reason for one hundred twenty (120) days

                                      -21-
<PAGE>

         after the granting of such consent, or if such assignment or sublease
         is modified or amended prior to its becoming effective, then and in
         either such event, Landlord's consent shall be deemed to have been
         withdrawn and Tenant shall not have the right to assign this Lease or
         to sublease all or any portion of the Premises without once again
         complying with the provisions and conditions of this Article 6. In no
         event shall Tenant agree to modify or amend any sublease to which
         Landlord has consented without Landlord's prior written consent.

         (g)      The joint and several liability of Tenant and any assignee or
         successor of Tenant under this Lease shall not be discharged, released
         or impaired in any respect by any agreement or stipulation made by
         Landlord modifying any of the obligations contained in this Lease, or
         by any waiver or failure by Landlord to enforce any of the obligations
         of this Lease, but in no event shall Tenant's continued liability
         exceed what its continuing liability would have been had the Lease not
         been modified except for those modifications, if any, which were
         consented to by Tenant.

         (h)      The listing of any name other than Tenant on the door of the
         Premises, on the Building directory or otherwise, shall not operate to
         vest any right or interest in this Lease or in the Premises in any
         other person or entity, nor shall such listing be deemed to be the
         consent of Landlord to any assignment or transfer of this Lease or to
         any sublease of the Premises or any portion thereof or the use or
         occupancy of the Premises or any portion thereof by others.

         (i)      Except as otherwise expressly provided herein, Tenant shall
         not have the right to transfer, assign, convey to any sublessee or,
         sublessor, or grant the benefit to any sublessee of, Tenant's rights
         set forth in Articles 15, 17, 18, 19 or 20 without the prior written
         consent of Landlord.

6.6      ACCEPTANCE OF RENT. If this Lease is assigned, whether or not in
         violation of the provisions of this Lease, Landlord may collect rent
         from the assignee. If all or any part of the Premises are sublet,
         whether or not in violation of this Lease, Landlord may, after default
         by Tenant and expiration of Tenant's time to cure such default, collect
         rent from the subtenant. In either event, Landlord shall apply the net
         amount collected to payment of Basic Rent and Additional Charges, but
         no such assignment, subletting, or collection shall be deemed a waiver
         of any of the provisions of this Article 6, an acceptance of the
         assignee or subtenant as a lessee, or a release of Tenant from the
         performance by Tenant of Tenant's obligations under this Lease.

                                    ARTICLE 7
                              REPAIRS AND SERVICES

7.1      LANDLORD REPAIRS. (a) Except as otherwise provided in this Lease,
         Landlord agrees to keep in good order, condition and repair the roof,
         the exterior and load bearing walls (including exterior glass), the
         foundation, the structural floor slabs and other structural elements of
         the Building, the common facilities of the Building (including all
         Essential Services as defined in Section 7.6, plumbing, mechanical,
         electrical and other Building systems and equipment installed by
         Landlord and servicing the Premises, but specifically excluding any
         supplemental or accessory heating, ventilation or air conditioning
         equipment or systems and telecommunications/computer systems and
         equipment exclusively servicing the Premises installed at Tenant's
         request or as a result of Tenant's requirements in excess of Building
         Standard design criteria), the Site and the exclusive, underground
         parking areas, all insofar as they affect the Premises, except that
         Landlord shall in no event be responsible to Tenant for the repair of
         glass in the

                                      -22-
<PAGE>

         Premises, the doors (or related glass and finish work) leading to the
         Premises (except to the extent such damage to the Premises is caused by
         the negligence or willful misconduct of Landlord, its agents,
         contractors or employees), or any condition in the Premises or the
         Building caused by any act or neglect of Tenant, its agents, employees,
         assignee, subtenants, invitees or contractors (except to the extent
         such damage is or should have been covered by policies of insurance
         required to be obtained by Landlord hereunder with respect to the
         Building which covers such condition). Landlord shall not be
         responsible to make any improvements or repairs to the Building other
         than as expressly in this Section 7.1 provided, unless expressly
         provided otherwise in this Lease. All of said repairs and any
         restorations or replacements required in connection therewith shall be
         of a quality and class at least equal to the original work and
         installations and shall be done in a good and workmanlike manner.

         (b)      Landlord shall never be liable for any failure to make repairs
         which Landlord has undertaken to make under the provisions of this
         Section 7.1 or elsewhere in this Lease unless Tenant has given notice
         to Landlord of the need to make such repairs, and Landlord has failed
         to commence to make such repairs within a reasonable time after receipt
         of such notice, or fails to proceed with reasonable diligence to
         complete such repairs.

         (c)      In the event that the Landlord fails to make a repair or
         replacement required to be made by Landlord pursuant to the terms of
         Section 7.1 and failed to commence to make such repairs within a
         reasonable time (not to exceed thirty (30) days) after receipt of
         Tenant's written notice to Landlord of Landlord's failure to so cure,
         or Landlord thereafter fails to proceed with reasonable diligence to
         complete such repair or restoration, Tenant may (but shall not be
         required to) make or cause such repairs or replacements to be made,
         provided that such repair or restoration shall be made in accordance
         with all requirements applicable to work or Alterations performed by
         Tenant under this Lease (other than the necessity to obtain Landlord's
         consent thereto) and provided, further, that Tenant shall not interfere
         with any other tenant's use or occupancy or the provision of services
         to other tenants. Landlord agrees to pay Tenant all sums incurred by
         Tenant in connection with Tenant's exercise of its self-help rights,
         together with interest thereon at a rate equal to two percent (2%) over
         the base rate in effect from time to time at Fleet National Bank.

7.2      TENANT REPAIRS. (a) Except as expressly provided in Section 7.1, Tenant
         covenants and agrees that, from and after the date that the possession
         of the Premises is delivered to Tenant and until the end of the Lease
         Term, Tenant, at its expense, will maintain in good order, condition
         and repair the Premises and every part thereof, and will make all
         required repairs thereto and/or replacements of portions thereof,
         excepting only those repairs for which Landlord is responsible under
         the terms of this Lease, reasonable wear and tear of the Premises, and
         damage by fire or other casualty or as a consequence of the exercise of
         the power of eminent domain; and shall surrender the Premises, at the
         end of the Lease Term, in such condition. Without limitation, Tenant
         shall continually during the Lease Term maintain the Premises in
         accordance with all laws, codes and ordinances from time to time in
         effect and all directions, rules and regulations of the proper officers
         of governmental agencies having jurisdiction, and the standards
         recommended by the Boston Board of Fire Underwriters, and shall, at
         Tenant's expense, obtain all permits, licenses and the like required by
         applicable law. To the extent that the Premises constitute a "Place of
         Public Accommodation" within the meaning of the Americans With
         Disabilities Act of 1990, Tenant shall be responsible, subject to the
         requirements of Section 5.2, for making the Premises comply with such
         Act. Tenant shall have the right to paint the stairwells in the
         Building provided that the same is done in conformance

                                      -23-
<PAGE>

         with applicable law and the Rules and Regulations and provided that
         Landlord's prior consent therefor is obtained, such consent not to be
         unreasonably withheld. Tenant shall not permit or commit any waste,
         and, notwithstanding the foregoing or the provisions of Article 12,
         Tenant shall be responsible for the cost of repairs and replacements to
         the Premises, the Building and the facilities of the Building, whether
         ordinary or extraordinary or structural or non-structural, when
         necessitated by Tenant, or its subtenant or assignee, moving property
         in or out of the Building or installation or removal of furniture,
         fixtures or other property or by the performance by Tenant, or its
         subtenant or assignee, of any Alterations or other work in the
         Premises. If the premium or rates payable with respect to any policy or
         policies of insurance purchased by Landlord or Agent with respect to
         the Building increases as a result of payment by the insurer of any
         claim arising from any act or neglect of Tenant, its assignee,
         subtenant, contractors or invitees, Tenant shall pay such increase,
         from time to time, within fifteen (15) days after demand therefor by
         Landlord as Landlord receives invoices from the insurance company with
         respect to such premiums, as Additional Charges. All of said repairs
         and any restorations or replacements required in connection therewith
         shall be of a quality and class at least equal to the original work and
         installations and shall be done in a good and workmanlike manner to the
         satisfaction of Landlord.

         (b)      If repairs or replacements are required to be made by Tenant
         pursuant to the terms hereof, Landlord may demand that Tenant make the
         same forthwith, and if Tenant refuses or neglects to commence such
         repairs or replacements within ten (10) days after such demand and
         complete the same with reasonable dispatch thereafter (except in the
         case of an emergency, in which event Landlord may make such repairs
         immediately), Landlord may (but shall not be required to) make or cause
         such repairs or replacements to be made (the provisions of Section
         14.18 being applicable to the costs thereof), and shall not be
         responsible to Tenant for any loss or damage whatsoever that may accrue
         to Tenant's stock or business by reason thereof.

7.3      FLOOR LOAD - HEAVY MACHINERY. (a) Tenant shall not place a load upon
         any floor in the Premises exceeding 80 pounds per square foot of live
         load plus 20 pounds per square foot partition allowance and which is
         allowed by law. Landlord reserves the right, in the exercise of its
         reasonable judgment, to prescribe the weight and position of all heavy
         business machines and heavy mechanical equipment, including safes,
         which shall be placed so as to distribute the weight. Business machines
         and mechanical equipment shall be placed and maintained by Tenant at
         Tenant's expense in settings sufficient, in Landlord's judgment, to
         absorb and prevent vibration, noise and annoyance. Tenant shall not
         move any safe, heavy machinery, heavy equipment, freight, bulky matter
         or fixtures into or out of the Building or place a load upon any
         stairwell, elevator or common area exceeding the floor load per square
         foot of area which such area was designed to carry without Landlord's
         prior consent, which consent may include a requirement to provide
         insurance, naming Landlord as an insured, in such amounts as Landlord
         may deem reasonable.

         (b)      If any such safe, machinery, equipment, freight, bulky matter
         or fixtures requires special handling, Tenant agrees to employ only
         persons holding a Master Rigger's License to do such work, and that all
         work in connection therewith shall comply with applicable laws and
         regulations. Any such moving shall be at the sole risk and hazard of
         Tenant, and Tenant will exonerate, indemnify and save Landlord harmless
         against and from any liability, loss, injury, claim or suit resulting
         directly or indirectly from such moving.

                                      -24-
<PAGE>

7.4      BUILDING SERVICES. (a) Landlord shall, on Business Days from 8:00 a.m.
         to 6:00 p.m. and on Saturdays from 9 a.m. to 1:00 p.m. ("Business
         Hours"), furnish heating, cooling and ventilation for occupants of the
         Premises under normal business operation at an occupancy of not more
         than one person per 150 square feet of Premises Rentable Area and an
         electrical load not exceeding 8.0 watts per square foot of Premises
         Rentable Area. The specifications and performance criteria for such
         air-conditioning, heating and ventilation systems are described on
         Exhibit M hereto. If Tenant shall require air conditioning, heating or
         ventilation outside the hours and days above specified ("Overtime
         Service"), Landlord shall furnish such Overtime Service upon reasonable
         advance notice from Tenant, and Tenant shall pay therefor such charges
         as may from time to time be in effect, not to exceed the Landlord's
         actual out-of-pocket costs therefor. In the event Tenant introduces
         into the Premises personnel or equipment which overloads the capacity
         of the Building system or in any other way interferes with the system's
         ability to perform adequately its proper functions, supplementary
         systems may, if and as needed, at Landlord's option, be provided by
         Landlord, at Tenant's expense.

         (b)      Landlord shall also provide:

                  (i)      Passenger elevator service in common with Landlord
                  and other tenants in the Building.

                  (ii)     Warm water for lavatory purposes and cold water (at
                  temperatures supplied by the municipality in which the
                  Building is located) for drinking, lavatory and cleaning
                  purposes. If Tenant uses water for any purpose other than for
                  ordinary lavatory and drinking purposes, Landlord may assess a
                  reasonable charge for the additional water so used, or install
                  a water meter and thereby measure Tenant's water consumption
                  for all purposes. In the latter event, Tenant shall pay the
                  cost of the meter and the cost of installation thereof and
                  shall keep such meter and installation equipment in good
                  working order and repair. Tenant agrees to pay for water
                  consumed, as shown on such meter, together with the sewer
                  charge based on such meter charges, as and when bills are
                  rendered, and if in default in making such payment Landlord
                  may pay such charges and collect the same from Tenant as
                  Additional Charges.

                  (iii)    Cleaning (including exterior window cleaning) and
                  janitorial services to the Premises on Business Days, provided
                  the same are kept in order by Tenant, substantially in
                  accordance with the cleaning times and standards for the
                  Building described in Exhibit K hereto. In the event that
                  Tenant is dissatisfied, in the exercise of its reasonable
                  judgment, with the contractor providing cleaning and
                  janitorial services to the Premises, Landlord shall use
                  reasonable efforts to cure such dissatisfaction with the
                  existing contractor or to replace such contractor with a
                  contractor reasonably acceptable to Tenant within a reasonable
                  time period.

                  (iv)     Free access to the Premises on Business Days during
                  Business Hours, and at all other times via a card key access
                  system, subject to security precautions from time to time in
                  effect, and subject always to restrictions based on emergency
                  conditions. Landlord will consult with Tenant in an effort to
                  coordinate Landlord's access system to the Building with
                  Tenant's access system to the Premises for compatibility.

                                      -25-
<PAGE>

                  (v)      Snow and ice removal to the walks, driveways and
                  parking areas which Tenant is entitled to use under this
                  Lease, and landscaping and maintenance of surrounding grounds.

                  (vi)     Routine operation and maintenance of the walks,
                  driveways and parking areas which Tenant is entitled to use
                  under the Lease, including striping of parking areas, and
                  reasonably appropriate lighting of the parking areas.

         (c)      Landlord or Agent may from time to time, but shall not be
         obligated to, provide one or more uniformed attendants in or about the
         lobby of the Building. Unless Landlord expressly agrees otherwise in
         writing, such attendant(s) shall serve functions such as assisting
         visitors and invitees of tenants and others in the Building, monitoring
         fire control and alarm equipment, and summoning emergency services to
         the Building as and when needed. Tenant expressly acknowledges and
         agrees that: (i) such attendants shall not serve as police officers,
         and will be unarmed, and will not be trained in situations involving
         potentially physical confrontation; and (ii) if provided, such
         attendants will be provided solely as an amenity to tenants of the
         Building for the sole purposes set forth above, and not for the purpose
         of securing any individual tenant premises or guaranteeing the physical
         safety of Tenant's Premises or of Tenant's employees, agents,
         contractors or invitees. If and to the extent that Tenant desires to
         provide security devices or personnel for the Premises or for such
         persons or their property, Tenant shall be responsible for so doing,
         after having first consulted with Landlord and after obtaining
         Landlord's consent, which shall not be unreasonably withheld. Landlord
         agrees to (i) install and maintain a card key access system within the
         Building in order to provide Tenant with access to the Building at all
         times, (ii) provide a security guard to patrol the Site during
         non-Business Hours and (iii) illuminate the Building and Site with
         reasonable lighting; however, Landlord expressly disclaims any and all
         responsibility and/or liability for the physical safety of Tenant's
         property, and for that of Tenant's employees, agents, contractors and
         invitees, and, without in any way limiting the operation of Article 10
         hereof, Tenant, for itself and its agents, contractors, invitees and
         employees, hereby expressly waives any claim, action, cause of action
         or other right which may accrue or arise as a result of any damage or
         injury to the person or property of Tenant or any such agent, invitee,
         contractor or employee, except to the extent that the same arises from
         the negligent act or omission of Landlord or its agents, employees or
         contractors. Tenant agrees that, as between Landlord and Tenant, it is
         Tenant's responsibility to advise its employees, agents, contractors
         and invitees as to necessary and appropriate safety precautions.

7.5      ELECTRICITY. (a) Landlord shall supply electricity to the Premises to
         meet a demand requirement not to exceed 8.0 watts per square foot of
         Premises Rentable Area for standard single-phase 120 volt alternating
         current and Tenant agrees in its use of the Premises (i) not to exceed
         such requirements and (ii) that its total connected lighting load will
         not exceed the maximum from time to time permitted under applicable
         governmental regulations. If, without in any way derogating from the
         foregoing limitation, Tenant shall require electricity in excess of the
         requirements set forth above, Tenant shall notify Landlord and Landlord
         may (without being obligated to do so) supply such additional service
         or equipment at Tenant's sole cost and expense. Landlord shall purchase
         and install, at Tenant's expense but at Landlord's actual cost
         therefor, all lamps, tubes, bulbs, starters, convenience outlets and
         ballasts. In order to assure that the foregoing requirements are not
         exceeded and to avert possible adverse affect on the Building's
         electric system, Tenant shall not, without Landlord's prior consent,
         connect any fixtures, appliances or equipment to the Building's
         electric distribution system other

                                      -26-
<PAGE>

         than personal computers, printers, facsimile transceivers, typewriters,
         pencil sharpeners, adding machines, photocopiers, word and data
         processors, clocks, radios, hand held or desk top calculators,
         dictaphones, desktop computers and other similar small electrical
         equipment normally found in business offices and not drawing more than
         15 amps at 120/208 volts.

         (b)      Tenant acknowledges that Basic Rent does not include the cost
         of providing convenience electricity to the Premises. As elsewhere
         provided, Tenant shall pay the Estimated Electricity Payment to
         Landlord with Basic Rent payments, and to the extent that the cost of
         providing convenience electricity to the Premises for any Operating
         Year exceeds the Estimated Electricity Payment, Tenant shall pay such
         excess as herein provided. Tenant's electricity usage in the Premises
         shall be measured by one or more so-called "check-meters," which shall
         be installed in the Premises as a part of Landlord's Work to be
         performed pursuant to Article 3. Landlord shall cause such meter(s) to
         be read periodically, but not lees often than once during each
         Operating Year, for the purpose of determining Tenant's actual
         electricity usage during such Operating Year. In order to reimburse
         Landlord for the cost of supplying electricity to the Premises, Tenant
         shall pay to Landlord, as Additional Charges, an amount equal to the
         "Building Average Rate," as hereinafter defined, multiplied by the
         number of kilowatt-hours of electricity used in the Premises during the
         Operating Year in question, as shown on such check-meter. The term
         "Building Average Rate," as used herein, shall mean the average cost to
         Landlord of supplying one (1) kilowatt-hour of electricity to the
         Building, and shall be computed by dividing the electric bill(s) for
         the Building for the Operating Year in question by (ii) the number of
         kilowatt-hours of electricity supplied to the Building during such
         Operating Year. In the event that the Building shall be metered for
         more than one rate applicable to the Premises, then the Premises shall
         be similarly check-metered at each rate applicable to the Premises. To
         the extent that the Estimated Electricity Payments theretofore made by
         Tenant for the Operating Year in question are less than the amount
         computed by Landlord as aforesaid, then Tenant shall pay the amount of
         such shortfall within thirty (30) days after being so advised by
         Landlord, but if Tenant's Estimated Electricity Payments exceed the
         amount due, then Landlord shall credit the excess against the next
         subsequent obligations of Tenant on account of Estimated Electricity
         Payments (or refund such excess if the Lease Term has expired and
         Tenant has no further obligation to Landlord). Upon not less than
         thirty (30) days' notice to Tenant, Landlord shall have the right to
         require the Tenant to pay the applicable electricity provider directly
         for Tenant's electricity used at the Premises in lieu of payment by the
         Tenant to Landlord or Landlord's vendor of the Estimated Electricity
         Payment, and Tenant covenants in such event to make such direct
         payments to the electricity provider as they become due.

         (c)      From time to time during the Lease Term, Landlord shall have
         the right to have an electrical consultant selected by Landlord make a
         survey of Tenant's electric usage, the result of which survey shall be
         conclusive and binding upon Landlord and Tenant. In the event that such
         survey shows that Tenant has exceeded the requirements set forth in
         Section 7.4(a) hereof, in addition to any other rights Landlord may
         have hereunder, Tenant shall, upon demand, reimburse Landlord for the
         cost of such survey and the coat, as determined by such consultant, of
         electricity usage in excess of such requirements as an Additional
         Charge.

         (d)      Landlord shall have the right to discontinue furnishing
         electricity to the Premises at any time and Tenant shall have the right
         to discontinue receiving electricity from Landlord at any time after
         Tenant has leased all of the rentable area within the Building, in each
         case upon not less than sixty (60) days' notice to the other party

                                      -27-
<PAGE>

         provided Landlord or Tenant, as applicable, and at the expense of the
         party exercising such election, shall separately meter the Premises
         directly to the applicable utility company. If either party exercises
         such right, from and after the effective date of such discontinuance,
         Landlord shall not be obligated to furnish electricity to the Premises,
         and

                  (i)      Tenant shall no longer be required to pay the
                  Estimated Electricity Payment portion of Basic Rent; and

                  (ii)     Landlord shall permit Landlord's existing wires,
                  risers, conduits and other electrical equipment of Landlord to
                  be used to supply electricity to Tenant provided that the
                  limits set forth in Section 7.4(a) hereof shall not be
                  exceeded, and Tenant shall be responsible for payment of all
                  electricity charges directly to such utility.

7.6      INTERRUPTION OF SERVICES. If Landlord breaches its obligations to
         supply any HVAC, elevator, plumbing or electrical service or reasonable
         means of access to the Premises (collectively, the "Essential
         Services") which pursuant to the terms of this Lease Landlord is
         obligated to supply in or about the Premises (collectively
         "Untenantable Condition") and such Untenantable Condition shall not be
         caused by any circumstance referred to in Article 12, Force Majeure or
         by any misconduct of Tenant or its officers, contractors, licensees,
         agents, employees, guests or visitors, and as a result of the
         Untenantable Condition, (i) Tenant is precluded from using the whole or
         any part of the Premises (the "Untenantable Premises") due to the fact
         that the Premises or a part thereof are untenantable for a period in
         excess of five (5) consecutive Business Days in any one instance
         (commencing after written notice from Tenant to Landlord of the
         Untenantable Condition as provided for herein), (ii) Tenant shall
         vacate the Untenantable Premises and cease doing business therein; and
         (iii) Tenant shall give notice to Landlord of the facts set forth in
         (i) and (ii) above making specific reference to this rent abatement
         provision, then in such event, the portion of the Basic Rent and
         Additional Charges allocable to the Untenantable Premises shall be
         fully abated for the period commencing on the sixth (6th) consecutive
         Business Day after all the conditions set forth in (i), (ii) and (iii)
         above shall first be satisfied and ending on the date the Untenantable
         Premises shall be rendered usable and Landlord shall have given notice
         thereof (or the date Tenant shall re-occupy the Untenantable Premises
         for conduct of its business, if earlier). If such Untenantable
         Condition affects a material portion of the Premises and continues for
         sixty (60) consecutive days, Tenant may elect to terminate this Lease
         by giving written notice to the Landlord (provided such Untenantable
         Condition still persists on the date of such notice), and this Lease
         shall cease and come to end without further liability or obligation on
         the part of either party upon delivery of such notice. This Section 7.6
         shall act as a waiver of any right to which Tenant is otherwise
         entitled by law to claim a constructive eviction by reason of
         Landlord's failure to provide supply such Essential Services. Landlord
         shall be responsible to repair any Essential Services which it is
         required to supply to the Tenant to the extent provided in Section 7.1
         hereof.

                                    ARTICLE 8
                               REAL ESTATE TAXES

8.1      DEFINITIONS. For the purposes of this Section 8.1, the following terms
         shall have the respective meanings set forth below:

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         (a)      "Taxes" shall mean the aggregate amount of all real estate and
         personal property taxes and any general or special assessments and any
         betterment assessments (exclusive of penalties thereon and penalty
         interest but inclusive of interest on assessments payable in
         installments) assessed or imposed upon with respect to the Tax Parcel
         for any Tax Year. There shall be excluded from Taxes all income,
         estate, succession, inheritance, transfer and franchise taxes imposed
         upon Landlord or in connection with the Tax Parcel; provided, however,
         that if at any time during the Lease Term the method of taxation of
         real estate shall be changed and as a result of any other tax or
         assessment, however denominated and including, without limitation, any
         franchise, income, profit, use, occupancy, gross receipts or rental tax
         shall be imposed upon Landlord or the owner of the Tax Parcel, or the
         rents or income therefrom, in substitution for, in whole or in part,
         any of the taxes or assessments listed in the preceding sentence, such
         other tax or assessment shall be included in and deemed a part of the
         Taxes but only to the extent that the same shall be payable if the Tax
         Parcel were the only real estate owned by Landlord. The amount of any
         special assessments for public improvements or benefits to be included
         in Taxes for any Tax Year, in the case where the same may, at the
         option of the taxpayer, be paid in installments, shall be limited to
         the amount of the installment due in respect of such Tax Year, together
         with any interest payable in connection therewith (other than interest
         payable by reason of the delinquent payment of such installment).

         (b)      "Tax Year" shall mean each period from July 1 through June 30
         (or such other fiscal period as may hereafter be adopted by applicable
         governmental authority as the fiscal year for any tax, levy or charge
         included in Taxes), any part or all of which occurs during the Lease
         Term.

         (c)      "Tax Expenses" shall mean all expenses, including, without
         limitation, attorneys' fees and disbursements and experts' and other
         witnesses' fees, incurred by Landlord in seeking to reduce the amount
         of any assessed valuation of the Tax Parcel, in contesting the amount
         or validity of any Taxes, or in seeking a refund of Taxes.

8.2      TENANT'S SHARE OF TAXES. From and after the Commencement Date, if the
         Taxes for any full Tax Year falling within the Lease Term shall exceed
         the Base Taxes, or if, in the case of a Tax Year only a fraction of
         which is included in the Lease Term, an amount of the Taxes for such
         Tax Year multiplied by such fraction exceeds the Base Taxes multiplied
         by such fraction (the amount of such excess in either case being
         hereinafter referred to as the "Tax Excess"), then Tenant shall pay to
         Landlord, as Additional Charges, Tenant's Proportionate Share of the
         Tax Excess and Tax Expenses, provided that Tenant shall not be required
         to pay Tenant's share of Taxes due for the period from the Commencement
         Date to and including June 30, 1999, until July 1, 1999, the date on
         which Base Taxes shall first be determinable. Tenant's Proportionate
         Share of the Tax Excess and Tax Expenses for each Tax Year shall be
         payable in monthly installments as follows:

         (a)      Subject to the proviso in the first sentence of this Section
         8.2, estimated payments by Tenant equal to one-twelfth (l/12th) of the
         estimated Tax Excess payable by Tenant during any Tax Year following
         June 30, 1999 shall be made on the first day of each and every calendar
         month during the Lease Term following June 30, 1999, in the fashion
         herein provided for the payment of Basic Rent. The monthly amount so to
         be paid to Landlord shall be sufficient to provide Landlord by the time
         Taxes and Tax Expenses are due with a sum equal to Tenant's required
         payments, as reasonably estimated by Landlord from time to time, on
         account of Tax Excess for the then current Tax Year. Promptly after
         receipt by Landlord of bills for such Taxes and Tax Expenses,

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         Landlord shall advise Tenant of the amount thereof and the computation
         of Tenant's payment on account of any Tax Excess together with evidence
         reasonably necessary for the Tenant to analyze such computation (e.g.,
         a copy of the relevant tax bill). Landlord shall pay to the taxing
         authority the Taxes when due, subject to Landlord's right to institute
         a tax abatement, reduction or other proceedings as provided in Section
         8.3. If estimated payments theretofore made by Tenant for the Tax Year
         covered by such bills exceed the required payments on account thereof
         for such Tax Year, Landlord shall credit the amount of overpayment
         against subsequent obligations of Tenant with respect to Basic Rent and
         Additional Charges (or refund such overpayment if the Lease Term has
         ended and Tenant has no further obligation to Landlord); but if the
         required payments on account thereof for such Tax Year are greater than
         estimated payments theretofore made on account thereof for such Tax
         Year, Tenant shall make payment to Landlord within thirty (30) days
         after being so advised by Landlord.

         (b)      If the Taxes for any Tax Year shall equal or be less than the
         Base Taxes, Tenant shall not be obligated to make any payments to
         Landlord pursuant to this Section 8.2 in respect of a Tax Excess for
         such Tax Year, but in no event shall Tenant be entitled to any refund
         or reduction in the Basic Rent by reason of such fact.

         (c)      It is understood that the provisions of this Section 8.2 are
         based upon the method of payment of real property taxes in effect at
         the date of this Lease, to wit, in quarter-annual installments in
         advance on the first day of February, May, August and November of each
         Tax Year. If such method of payment is hereafter changed, Landlord
         shall have the right to change the method by which Tenant pays Tenant's
         Proportionate Share of a Tax Excess to a method of periodic payments
         which provides Landlord with the full payment of Tenant's Proportionate
         Share of such Tax Excess in respect of any installment of Taxes by the
         date on which such installment becomes due.

8.3      REFUND OF TAXES. If requested in writing by Tenant, Landlord shall
         consult with Tenant prior to instituting a tax abatement, reduction or
         other proceedings to challenge the appraised or assessed value of the
         Tax Parcel determined by the tax assessor and thereby reduce the Taxes
         assessed against the Tax Parcel, but only Landlord shall have the right
         to institute such proceedings; provided, however, that if after
         Landlord files an application with applicable governmental authorities
         for reduction of the assessed valuation of the Tax Parcel (any such
         application being herein called a "Tax Protest"), Landlord does not
         intend to prosecute such Tax Protest with reasonable diligence or to
         commence an action or proceeding in a court of appropriate jurisdiction
         seeking judicial review of the denial of any Tax Protest or to appeal
         any adverse decision (any such action or proceeding being herein called
         a "Tax Proceeding"), then Landlord shall notify Tenant of such
         intention at least fifteen (15) days prior to the latest date on which
         such a Tax Protest validly may be filed or such a Tax Proceeding
         validly may be commenced, as the case may be; and Tenant shall have the
         right by notice in writing to Landlord given not more than seven (7)
         days after Landlord has so notified Tenant of Landlord's intention or,
         if Landlord has not filed a Tax Protest and does not intend to file a
         Tax Protest, by giving notice in writing to Landlord that Tenant, in
         the exercise of its reasonable discretion, requests that the Landlord
         file a Tax Protest, to require Landlord to file such a Tax Protest or
         commence and diligently prosecute such a Tax Proceeding, as the case
         may be. If Landlord shall file such a Tax Protest or commence such a
         Tax Proceeding, as the case may be, in accordance with the requirements
         of this Section 8.3, Landlord shall have the right to settle or
         compromise the same without the consent of Tenant, provided that it
         does so in good faith. Upon Tenant's request, Landlord shall provide
         Tenant with a copy of all papers filed by Landlord in connection with
         any such Tax Protest or Tax Proceeding. Tenant's rights under this
         Section 8.3 may be exercised

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         at any time after the date hereof in respect of Tax Years occurring
         subsequent to the 1998-1999 Tax Year. Should Landlord be successful in
         any such Tax Proceeding and obtain a refund for any Tax Year or Years
         in respect of which Tenant shall have made a payment to Landlord,
         pursuant to Section 8.2 hereof, Landlord shall credit Tenant's
         Proportionate Share of such refund (or, in the case of a refund of
         Taxes for a Tax Year, only a fraction of which is included in the Lease
         Term, such fraction thereof) against the monthly installment or
         installments of Basic Rent next falling due under this Lease, or if the
         Lease Term has expired and Tenant has no further obligations to
         Landlord, such amount shall be refunded by Landlord to Tenant. In
         calculating the amount of any such credit or payment, Landlord shall
         have the right to deduct from such refund all Tax Expenses incurred by
         Landlord in obtaining the same. The provisions of this Section 8.3
         shall survive the expiration of the Lease Term.

                                    ARTICLE 9
                               OPERATING EXPENSES

9.1      DEFINITIONS. For the purposes of this Article 9, the following terms
shall have the respective meanings set forth below:

         (a)      "Operating Year" shall mean the calendar year within which the
         Commencement Date occurs and each subsequent calendar year, any part or
         all of which falls within the Lease Term.

         (b)      "Base Operating Expenses" shall mean the actual Operating
         Expenses incurred for the calendar year ending December 31, 1999
         (excluding the cost of providing convenience electricity to those
         portions of the Building leased or intended to be leased to tenants),
         subject to the provisions of Section 9.1(d), and provided that, if
         during any portion of the calendar year ending December 31, 1999, less
         than all of the Building and the building on the site to be known as
         890 Winter Street (the construction and completion of which are assumed
         for purposes of extrapolating Base Operating Expenses herein) are
         occupied by tenants or, if Landlord was not supplying all tenants with
         the services being supplied to the Tenant hereunder, then the Operating
         Expenses actually incurred shall be reasonably extrapolated by Landlord
         on an item-by-item basis to be the reasonable Operating Expenses that
         would have been incurred if the Building and the building on the site
         to be known as 890 Winter Street were fully occupied and such services
         were being supplied to all tenants. Such extrapolated Operating
         Expenses shall, for all purposes hereof, be deemed to be the Base
         Operating Expenses hereunder.

         (c)      "Tenant's Proportionate Share" shall be a fraction, (i) the
         numerator of which is the Premises Rentable Area, and (ii) the
         denominator of which is the Building Rentable Area multiplied by 1.00.

         (d)      "Operating Expenses" shall mean the aggregate of (i) 100% of
         Building Operating Expenses and (ii) 55% of Common Site Operating
         Expenses (subject to adjustment to reflect the actual ratio of the
         rentable square footage of the Building to the other building to be
         constructed at the Complex by an affiliate of Landlord), and subject to
         such percentage allocation, includes all costs and expenses paid or
         incurred by or on behalf of Landlord with respect to the operation,
         administration, cleaning, repair, maintenance and management of the
         Building and the Site all as set forth in Exhibit E annexed hereto,
         provided that, if during any portion of the Operating Year for which
         Operating Expenses are being computed, less than all of the Building
         and the building on the site to be known as 890 Winter Street (the
         construction and completion of which are assumed for purposes of
         extrapolating Base Operating Expenses herein) are

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         occupied by tenants or, if Landlord was not supplying all tenants with
         the services being supplied to the Tenant hereunder, then the Operating
         Expenses actually incurred shall be reasonably extrapolated by Landlord
         on an item-by-item basis to be the reasonable Operating Expenses that
         would have been incurred if the Building and the building on the site
         to be known as 890 Winter Street were fully occupied and such services
         were being supplied to all tenants.

         (e)      "Building Operating Expenses" for any Operating Year shall
         mean all Operating Expenses incurred in respect of the Building,
         exclusive of Common Site Operating Expenses, for such Operating Year.

         (f)      "Common Site Operating Expenses" for any Operating Year shall
         mean all Operating Expenses, exclusive of Building Operating Expenses,
         incurred in respect of common facilities located on the Site which
         service all buildings (including the Building) from time to time
         located on the Site including, without limiting the generality of the
         foregoing, property management fees and expenses, common roadways,
         common driveways, non-exclusive parking areas, utility lines and
         equipment, drainage areas and related fixtures and equipment, and any
         other similar improvements constructed on the Site, whether above or
         below ground, which Landlord is required by any agreement entered into
         in connection with the construction of the Building to operate or
         maintain or to contribute to the cost of the operation or maintenance
         thereof to the extent such expenses are payable with respect to the
         buildings on the Site owned by Landlord or its affiliates.

9.2      EXCESS OPERATING EXPENSES.

         (a)      In the event that, for any Operating Year following December
         31, 1999, Operating Expenses shall exceed Base Operating Expenses, then
         Tenant shall pay to Landlord, as Additional Charges, an amount equal to
         Tenant's Proportionate Share of such excess Operating Expenses, such
         amount to be apportioned for any portion of an Operating Year in which
         the term of this Lease ends.

         (b)      Payments by Tenant equal to one-twelfth (l/12th) of the
         estimated amount of excess Operating Expenses attributable to Tenant
         for any Operating Year shall be made on the first day of each and every
         calendar month during the Lease Term, commencing January 1, 2000, in
         the fashion herein provided for the payment of Basic Rent.

         (c)      Tenant may request Landlord to reduce services being provided
         to the Premises resulting from Tenant's lack of occupancy of the
         Premises or a portion thereof if and to the extent that such reduction
         in services is practicable in Landlord's reasonable judgment and can be
         accomplished without otherwise affecting Building services provided to
         other tenants of the Building, and provided further that any such
         reduction in services is in compliance with applicable law. If Tenant's
         use of the Premises, or any portion thereof, is ever such that the
         building standard services furnished to all or any portion of the
         Premises is substantially less than the services required by Landlord
         to be provided hereunder, and Tenant can demonstrate to Landlord's
         reasonable satisfaction the amount (or reasonable estimate thereof) of
         the reduction in Operating Expenses attributable thereto, then a credit
         adjustment shall be made to the Additional Charges payable by Tenant to
         reflect such savings.

         The monthly amount so to be paid to Landlord shall be sufficient to
provide Landlord by the end of each Operating Year a sum equal to Tenant's
required payments, as reasonably estimated by Landlord from time to time during
each Operating Year, on account of excess

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Operating Expenses for such Operating Year. After the end of each Operating
Year, Landlord shall submit to Tenant a reasonably detailed accounting of
Operating Expenses for such Operating Year, and Landlord shall certify to the
accuracy thereof, having exercised reasonable efforts to ensure that invoices
for Operating Expenses reflect actual services provided. If estimated payments
theretofore made for such Operating Year by Tenant exceed Tenant's required
payment on account thereof for such Operating Year, according to such
statement, Landlord shall credit the amount of overpayment against subsequent
obligations of Tenant with respect to Basic Rent and Additional Charges (or
refund such overpayment if the Lease Term has ended and Tenant has no further
obligation to Landlord); but, if the required payments on account thereof for
such Operating Year are greater than the estimated payments (if any) theretofore
made on account thereof for such Operating Year, Tenant shall make payment to
Landlord within thirty (30) days after being so advised by Landlord. Landlord
shall have the same rights and remedies for the nonpayment by Tenant of any
payments due on account of Operating Expenses as Landlord has hereunder for the
failure of Tenant to pay Basic Rent.

9.3      TENANT AUDIT RIGHTS. (a) If Tenant shall so request, within one-hundred
         twenty (120) days after receipt of any accounting required to be
         presented by Landlord hereunder (or if Landlord has failed to deliver
         such accounting, at any time), Landlord shall permit Tenant, at
         Tenant's expense and during normal Business Hours, to review at
         Landlord's office Landlord's invoices relating to Operating Expenses
         for the Operating Year in respect of which such accounting was (or
         should have been) prepared for the purpose of verifying any accounting
         that Landlord is required to give hereunder, provided that Tenant shall
         be limited to one such audit right per calendar year. In making any
         such examination, Tenant agrees, and shall cause its auditors,
         accountants and any other employees, agents or contractors having
         access to such information to agree, to keep strictly confidential (i)
         any and all information contained in such books and records, and (ii)
         the circumstances and details pertaining to such examination, including
         without limitation the nature of any dispute in respect of Operating
         Expenses and the nature or details of any settlement thereof; and
         Tenant will confirm and cause its auditors, accountants, employees,
         agents and contractors to confirm such agreement in writing, if so
         requested by Landlord, prior to such examination. If Tenant shall not
         request any such review within the one-hundred twenty (120)-day period
         hereinabove referred to, then Landlord's accounting shall be binding
         and conclusive absent manifest error. During the pendency of any such
         examination, Tenant shall make all payments claimed by Landlord to be
         due, such payments to be without prejudice to Tenant's position.

         (b)      If Tenant elects to conduct such an examination, as provided
         in paragraph (a), then any such accounting by Landlord shall be binding
         and conclusive upon Tenant unless, within one-hundred eighty (180) days
         after Tenant's receipt of Landlord's accounting, Tenant shall notify
         Landlord in writing that Tenant disputes the correctness of such
         accounting, specifying the particular respects in which the accounting
         is claimed to be incorrect. If such dispute has not been resolved by
         agreement within thirty (30) days after Tenant's notice of such
         dispute, then Tenant may, within thirty (30) additional days after the
         expiration of the first such thirty (30)-day period, submit the matter
         to arbitration in accordance with Article 21. If Tenant shall fail to
         submit the matter to arbitration within such additional thirty (30)-day
         period, then the accounting shall be conclusively deemed to be correct.
         Pending resolution by agreement or arbitration, Tenant shall make any
         payments claimed by Landlord to be due on account of Operating
         Expenses, such payment to be without prejudice to Tenant's position.
         Any decision by an arbitrator shall be final and binding on the
         parties. If the dispute shall be resolved in Tenant's favor, Landlord
         shall forthwith credit the amount overpaid by Tenant against amounts
         subsequently coming due on account of Basic Rent or Additional Charges.
         Each

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         party shall bear one-half (1/2) of the cost of such arbitrator. If the
         audit reveals that the Landlord has overcharged the Tenant by more than
         three percent (3%) with respect to the Operating Expenses, Landlord
         shall pay the cost of such audit and shall refund the amount of the
         excess Operating Expenses which were overcharged with interest at the
         per annum base or prime rate in effect from time to time of Fleet
         National Bank plus two percent (2%).

                                   ARTICLE 10
                            INDEMNITY AND INSURANCE

10.1     TENANT'S AND LANDLORD'S INDEMNITY. (a) Except to the extent that such
         claims arise from the negligent acts or omissions of Landlord or its
         agents, contractors or employees, Tenant agrees to indemnify and save
         harmless Landlord, its members, agents, contractors and employees from
         and against all claims, loss, cost, damage or expense asserted by or on
         behalf of any person, firm, corporation or public authority of whatever
         nature arising: (i) from any accident, injury or damage whatsoever to
         any person, or to the property of any person, occurring in or about the
         Premises; (ii) from any accident, injury or damage occurring elsewhere
         (other than on the Premises) in or about the Building or the Site to
         the extent that such accident, damage or injury results or is claimed
         to have resulted from an act or omission on the part of Tenant or
         Tenant's agents, employees or contractors; or (iii) in connection with
         the conduct or management of the Premises or of any business therein,
         or any thing or work whatsoever done, or any condition created (other
         than by Landlord) in or about the Premises; and, in any case, occurring
         after the date of this Lease until the end of the Lease Term and
         thereafter so long as Tenant is in occupancy of any part of the
         Premises. This indemnity and hold harmless agreement shall include
         indemnity against all losses, costs, damages, expenses and liabilities
         incurred in or in connection with any such claim or proceeding brought
         thereon, and the defense thereof by counsel of the insurer (if such
         claim is covered by insurance) or otherwise by counsel reasonably
         satisfactory to Landlord, including, without limitation, reasonable
         attorneys' fees and costs at both the trial and appellate levels.

         (b)      Landlord agrees to indemnify and save harmless Tenant, its
         shareholders, directors, officers, employees, agents and contractors
         from and against all claims, loss, cost, damage or expense asserted by
         or on behalf of any person, firm, corporation or public authority of
         whatever nature arising from any accident, injury or damage, to the
         extent that such accident, damage or injury results or is claimed to
         have resulted from an act or omission on the part of Landlord or
         Landlord's agents, employees or contractors, occurring after the date
         of this Lease until the end of the Lease Term. This indemnity and hold
         harmless agreement shall include indemnity against all losses, costs,
         damages, expenses and liabilities incurred in or in connection with any
         such claim or proceeding brought thereon, and the defense thereof,
         including, without limitation, reasonable attorneys' fees and costs at
         both the trial and appellate levels.

         (c)      In the event any claim, loss, cost, damage or expenses
         referenced in subparagraph (a) or (b) above is due to the joint or
         concurrent negligence of Landlord and Tenant, or their respect agents,
         contractors and employees, each of Landlord and Tenant shall be
         responsible for, and shall indemnify and hold harmless the other from,
         such claims, losses, costs, damage or expense to the extent of their
         respective negligence.

10.2     GENERAL LIABILITY INSURANCE. Tenant agrees to maintain in full force
         from the date upon which Tenant first enters the Premises for any
         reason, throughout the Lease Term and thereafter, so long as Tenant is
         in occupancy of any part of the Premises, a

                                      -34-
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         policy of commercial general liability and property damage insurance
         (including broad form contractual liability, independent contractor's
         hazard and completed operations coverage) under which Tenant is named
         as an insured and Landlord, Agent (and such other persons as are in
         privity of estate with Landlord as may be set out in a notice from time
         to time) are named as additional insureds, and under which the insurer
         agrees to indemnify and hold Landlord, Agent and those in privity of
         estate with Landlord, harmless from and against all cost, expense
         and/or liability arising out of or based upon any and all claims,
         accidents, injuries and damages set forth in Section 10.1(a). Each such
         policy shall be issued by one or more insurers in a financial size
         category of not less than XIV and with general policyholders rating of
         not less than A as rated in the most current available "Bests"
         insurance reports, or the then equivalent thereof, and licensed to do
         business in the Commonwealth of Massachusetts and authorized to issue
         such policies and such policies shall have commercially reasonable
         deductibles. Tenant may satisfy such insurance requirements by
         including the Premises in a so-called "blanket" and/or "umbrella"
         insurance policy, provided that the amount of coverage allocated to the
         Premises shall fulfill the foregoing requirements. Each policy of
         insurance procured by Tenant shall contain endorsements providing that
         (i) such policy shall be non-cancelable and non-amendable with respect
         to Landlord, Agent and Landlord's said designees without thirty (30)
         days' prior notice to Landlord and such designees, (ii) written on an
         "occurrence" basis, and (iii) in at least the amounts of the Initial
         General Liability Insurance specified in Section 1.2, and a certificate
         of insurance evidencing the insurance carried in compliance with the
         requirements of this Section 10.2 shall be delivered to Landlord.

10.3     TENANT'S RISK. Tenant agrees to use and occupy the Premises and to use
         such other portions of the Building and the Site as Tenant is herein
         given the right to use at Tenant's own risk. Except to the extent that
         such claims arise from the negligent acts or omissions of Landlord or
         its agents, contractors or employees, neither Landlord nor Landlord's
         insurers shall have any responsibility or liability for any loss of or
         damage to Tenant's Removable Property, Tenant's Alterations and any
         paneling or other wall finishings or coverings other than normal
         painting. Tenant shall carry "all-risk" property insurance on a
         "replacement cost" basis, insuring Tenant's Removable Property and any
         Alterations installed by Tenant pursuant to Section 5.2, to the extent
         that the same have not become the property of Landlord, and other
         so-called improvements and betterments and such policies shall have
         commercially reasonable deductibles. Tenant may satisfy such insurance
         requirements by including the Premises in a so-called "blanket" and/or
         "umbrella" insurance policy, provided that the amount of coverage
         allocated to the Premises shall fulfill the foregoing requirements. The
         provisions of this Section 10.3 shall be applicable from and after the
         execution of this Lease and until the end of the Lease Term, and during
         such further period as Tenant may use or be in occupancy of any part of
         the Premises or of the Building.

10.4     CERTIFICATES OF INSURANCE. On or prior to the time Tenant and/or its
         contractors enter the Premises in accordance with this Lease and
         thereafter not less than thirty (30) days prior to the expiration date
         of each expiring policy, insurance company certificates of such
         policies issued by such insurers shall be delivered by Tenant to
         Landlord.

10.5     INJURY CAUSED BY THIRD PARTIES. Except to the extent that such claims
         arise from the negligent acts or omissions of Landlord or its agents,
         employees or contractors, Tenant agrees that Landlord shall not be
         responsible or liable to Tenant, or to those claiming by, through or
         under Tenant, for any loss or damage that may be occasioned by or
         through the acts or omissions of persons occupying adjoining premises
         or any part of the premises adjacent to or connecting with the Premises
         or any part of the Building or

                                      -35-
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         otherwise. Without in any way limiting or otherwise affecting the
         provisions of the preceding sentence, Landlord agrees to use reasonable
         efforts to enforce compliance with the provisions of any other lease in
         the Building, but this sentence shall not be interpreted or construed
         so as to obligate Landlord to commence litigation against other tenants
         of the Building or to exercise any termination rights under any other
         lease for space in the Building.

10.6     WAIVER OF SUBROGATION.

         (a)      Landlord and Tenant shall each endeavor to secure an
                  appropriate clause in or an endorsement to each property
                  insurance policy obtained by it and covering the Site, the
                  Building, the Premises, Tenant's Alterations, or Tenant's
                  Removable Property, as applicable, pursuant to which the
                  respective insurance companies waive subrogation or permit the
                  insured, prior to any loss, to agree with a third party to
                  waive any claim it might have against said third party. The
                  waiver of subrogation or permission for waiver of any claim
                  hereinbefore referred to shall extend to the agents of each
                  party and, in the case of Tenant, shall also extend to all
                  other persons and entities occupying or using the Premises in
                  accordance with the terms of this Lease. If and to the extent
                  that such waiver or permission can be obtained only upon
                  payment of an additional charge, then in the case of
                  Landlord's insurance policy, such additional charge shall be
                  an Operating Expense and, in the case of Tenant's insurance
                  policy, Landlord shall pay such charge upon demand, and if
                  Landlord shall fail or refuse to pay any such charge within
                  thirty (30) days of demand therefor, Landlord shall be deemed
                  to have agreed that Tenant shall be free of any further
                  obligations under the provisions hereof relating to such
                  waiver or permission for so long as such waiver of subrogation
                  is only available upon payment of a charge which Landlord
                  declines to pay. In the event that either Landlord or Tenant
                  shall he unable at any time to obtain one of the provisions
                  referred to above in any of its insurance policies, Landlord
                  or Tenant, as the case may be, shall promptly notify the
                  other.

         (b)      Subject to the foregoing provisions of this Section 10.6 and
                  insofar as may be permitted by the terms of the insurance
                  policies carried by it, each party hereby releases the other
                  and its members, partners, agents and employees (and in the
                  case of Tenant, all other persons and entities occupying or
                  using the Premises in accordance with the terms of this Lease
                  with respect to any claim, including a claim for negligence)
                  which it might otherwise have against the other party for
                  loss, damages or destruction with respect to its property by
                  fire or other casualty (including rentable value or business
                  interruption, as the case may be) occurring during the Lease
                  Term which could be covered under an all-risk full replacement
                  cost insurance policy, whether or not actually obtained.

                                   ARTICLE 11
                         LANDLORD'S ACCESS TO PREMISES

11.1     LANDLORD'S RIGHT OF ENTRY. Landlord and Agent shall have the right,
         without being deemed thereby to evict Tenant from the Premises or any
         part thereof or otherwise to violate any of the terms of this Lease or
         any of Tenant's rights hereunder, (a) to enter and pass through the
         Premises or any part or parts thereof (i) by appointment, such
         appointment not to be unreasonably withheld, to examine the Premises
         and to show them to prospective or existing mortgagees, purchasers or
         tenants of any part of the Building, (ii) for the purpose of performing
         such maintenance and making such repairs or changes in or to the
         Premises or in or to the Building or its facilities as may be

                                      -36-
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         provided for or permitted by this Lease or may be mutually agreed upon
         by the parties or as Landlord may be required to make by laws and
         requirements of public authorities, (iii) at such times as such entries
         shall be required by circumstances of emergency affecting the Premises
         or the Building, provided that in such event, if practicable, Landlord
         or its agents shall be accompanied by a designated representative of
         Tenant or member of the police, fire, water or other municipal
         department concerned or of a recognized protection company or of a
         public utility company which is concerned, and (b) to take all
         materials into and upon the Premises which may be required for any
         repairs, changes or maintenance and to store the same therein for a
         reasonable time as reasonably required in connection with the
         completion of such repairs. Landlord's rights under this Section 11.1
         shall be exercised in such manner as to create the least practicable
         interference with Tenant's use of the Premises; provided, however, that
         the foregoing shall not obligate Landlord to perform any work outside
         of Business Hours on Business Days except in those instances when such
         work will cause an undue interruption in Essential Services. Except in
         the case of an emergency which makes notice to Tenant impracticable,
         any entry on or interruption of Essential Services to the Premises by
         Landlord pursuant to this Section 11.1 shall be made after reasonable
         notice to Tenant.

11.2     LANDLORD'S RIGHT TO CHANGE ENTRIES. ETC. Landlord shall have the right
         at any time without thereby creating any actual or constructive
         eviction or incurring any liability to Tenant therefor, and without
         abatement in rent, to change the arrangement or location of lobbies,
         entrances, passageways, doors, doorways, stairways, elevators,
         corridors and other like portions of the Building outside of the
         Premises, provided that such change does not interfere with Tenant's
         access to the Premises.

11.3     EXCAVATION. In the event that an excavation or any construction should
         be made for building or other purposes upon land adjacent to the
         Building, or should be authorized to be made, Tenant shall, if
         necessary, afford to the person or persons causing or authorized to
         cause such excavation or construction, license to enter the Premises
         for the purpose of doing such work as shall reasonably be necessary to
         protect or preserve the wall or walls of the Building, or the Building,
         from injury or damage and to support them by proper foundations,
         pinning and/or underpinning or otherwise. Landlord will exercise
         reasonable efforts to effect such work during non-Business Hours
         without cost or expense to Tenant.

                                   ARTICLE 12
                           FIRE, EMINENT DOMAIN. ETC.

12.1     ABATEMENT OF RENT. If the Premises and/or the building systems which
         service the Premises, including the HVAC system, shall be damaged by
         fire or casualty or if a portion of the Building other than the
         Premises shall be damaged by fire or casualty such that the Tenant does
         not have reasonable access to the Premises or if the common areas of
         the Building systems are substantially damaged by fire or other
         casualty, Basic Rent and Additional Charges payable by Tenant shall
         abate proportionately for the period in which, by reason of such
         damage, there is substantial interference with Tenant's use of the
         Premises, having regard for the extent to which Tenant may be required
         to discontinue Tenant's use of all or a portion of the Premises, but
         such abatement or reduction shall end (i) in the event of damage to the
         Premises, thirty (30) days after Landlord shall have substantially
         restored the Premises (excluding any Alterations made by Tenant
         pursuant to Section 5.2) to the condition in which they were prior to
         such damage or (ii) in the event of damage to a portion of the Building
         other than the Premises, Landlord shall have provided Tenant with
         reasonable access to the

                                      -37-
<PAGE>

         Premises. Should Tenant reoccupy a portion of the Premises as to which
         Basic Rent and Additional Charges have been abated, for the purpose of
         conducting business prior to the date that the same is made tenantable,
         Basic Rent and Additional Charges shall be apportioned and payable by
         Tenant in proportion to the part of the Premises occupied by Tenant. If
         the Premises shall be affected by any exercise of the power of eminent
         domain, Basic Rent and Additional Charges payable by Tenant shall be
         justly and equitably abated and reduced according to the nature and
         extent of the loss of use thereof suffered by Tenant. In no event shall
         Landlord have any liability for damages to Tenant for inconvenience,
         annoyance, or interruption of business arising from such fire, casualty
         or eminent domain.

12.2     LANDLORD'S RIGHT OF TERMINATION. If the Premises or the Building are
         substantially damaged by fire or casualty (the term "substantially
         damaged" meaning damage of such a character that the same cannot, in
         ordinary course, reasonably be expected to be repaired within
         one-hundred twenty (120) days from the time that repair work would
         commence), or if any part of the Building is taken by any exercise of
         the right of eminent domain, then Landlord shall have the right to
         terminate this Lease (even if Landlord's entire interest in the
         Premises may have been divested) by giving notice of Landlord's
         election so to do within one-hundred twenty (120) days after the
         occurrence of such casualty or the effective date of such taking,
         whereupon this Lease shall terminate thirty (30) days after the date of
         such notice with the same force and effect as if such date were the
         date originally established as the expiration date hereof.

12.3     RESTORATION. If this Lease shall not be terminated pursuant to Section
         12.2, Landlord shall thereafter use due diligence to restore the
         Premises (excluding any Alterations made by Tenant pursuant to Section
         5.2) to proper condition for Tenant's use and occupation, provided that
         Landlord's obligation shall be limited to the amount of insurance
         proceeds available therefor. If, for any reason, such restoration shall
         not be substantially completed within six (6) months after the
         expiration of the one hundred twenty (120) day period referred to in
         Section 12.2 (which six-month period may be extended for such periods
         of time as Landlord is prevented from proceeding with or completing
         such restoration for any cause beyond Landlord's reasonable control,
         but in no event for more than an additional three (3) months), Tenant
         shall have the right to terminate this Lease by giving notice to
         Landlord thereof within thirty (30) days after the expiration of such
         period (as so extended) provided that such restoration is not completed
         within such period. This Lease shall cease and come to an end without
         further liability or obligation on the part of either party thirty (30)
         days after such giving of notice by Tenant unless, within such 30 day
         period, Landlord substantially completes such restoration. Such right
         of termination shall be Tenant's sole and exclusive remedy at law or in
         equity for Landlord's failure so to complete such restoration, and time
         shall be of the essence with respect thereto.

12.4     AWARD. Landlord shall have and hereby reserves and excepts, and Tenant
         hereby grants and assigns to Landlord, all rights to recover for
         damages to the Property and the leasehold interest hereby created, and
         to compensation accrued or hereafter to accrue by reason of such
         taking, damage or destruction, and by way of confirming the foregoing,
         Tenant hereby grants and assigns, and covenants with Landlord to grant
         and assign to Landlord, all rights to such damages or compensation, and
         covenants to deliver such further assignments and assurances thereof as
         Landlord may from time to time request, and Tenant hereby irrevocably
         appoints Landlord its attorney-in-fact to execute and deliver in
         Tenant's name all such assignments and assurances. Nothing contained
         herein shall be construed to prevent Tenant from prosecuting in any
         condemnation proceedings a claim for the value of any of Tenant's
         Removable Property installed in the

                                      -38-
<PAGE>

         Premises by Tenant at Tenant's expense and for relocation expenses,
         provided that such action shall not affect the amount of compensation
         otherwise recoverable by Landlord from the taking authority.

12.5     LANDLORD'S INSURANCE. Landlord agrees to maintain in full force and
         effect, during the Lease Term, "all risk" property damage insurance in
         an amount equal to full replacement cost and with such deductibles as
         may from time to time be carried by reasonably prudent owners of
         similar buildings in the area in which the Building is located.
         Landlord also agrees to maintain in full force from the date upon which
         Tenant first enters the Premises throughout the Lease Term and
         thereafter, so long as Tenant is in occupancy of any part of the
         Premises, a policy of commercial general liability insurance in amounts
         at lease equal to those set forth in the definition of Initial General
         Liability Insurance above. Landlord may satisfy such insurance
         requirements by including the Building in a so-called "blanket" and/or
         umbrella insurance policy, provided that the amount of coverage
         allocated to the Building shall fulfill the foregoing requirements.
         Such policies shall be issued by one or more insurers in a financial
         size category of not less than X and with general policyholders rating
         of not less than A as rated in the most current available "Bests"
         insurance reports, or the then equivalent thereof, and licensed to do
         business in the Commonwealth of Massachusetts and authorized to issue
         such policies and such policies shall have commercially reasonable
         deductibles. Landlord shall deliver to Tenant a certificate of
         insurance evidencing the insurance carried in compliance with the
         requirements of this Section 12.6 on or before the Commencement Date.

                                   ARTICLE 13
                                     DEFAULT

13.1     TENANT'S DEFAULT. (a) If at any time subsequent to the date of this
         Lease any one or more of the following events (herein referred to as a
         "Default of Tenant") shall happen:

                  (i)      Tenant shall fail to pay the Basic Rent or Additional
                  Charges hereunder when due and such failure shall continue for
                  five (5) full Business Days after written notice to Tenant
                  from Landlord, except that, if in this Lease no time period is
                  specified for the payment of Additional Charges hereunder by
                  Tenant to Landlord, then, in such circumstance only, Tenant
                  shall fail to pay such Additional Charges within thirty (30)
                  days after notice to Tenant of such non-payment; or

                  (ii)     Tenant shall neglect or fail to perform or observe
                  any other covenant herein contained on Tenant's part to be
                  performed or observed and Tenant shall fail to remedy the same
                  within thirty (30) days after notice to Tenant specifying such
                  neglect or failure, or if such failure is of such a nature
                  that Tenant cannot reasonably remedy the same within such
                  thirty (30) day period, Tenant shall fail to commence promptly
                  to remedy the same and to prosecute such remedy to completion
                  with diligence and continuity; or

                  (iii)    Tenant's leasehold interest in the Premises shall be
                  taken on execution or by other process of law directed against
                  Tenant; or

                  (iv)     Tenant shall make an assignment for the benefit of
                  creditors or shall be adjudicated insolvent, or shall file any
                  petition or answer seeking any reorganization, arrangement,
                  composition, readjustment, liquidation, dissolution

                                      -39-
<PAGE>

                  or similar relief for itself under any present or future
                  Federal, State or other statute, law or regulation for the
                  relief of debtors (other than the Bankruptcy Code, as
                  hereinafter defined), or shall seek or consent to or acquiesce
                  in the appointment of any trustee, receiver or liquidator of
                  Tenant or of all or any substantial part of its properties, or
                  shall admit in writing its inability to pay its debts
                  generally as they become due; or

                  (v)      An Event of Bankruptcy (as hereinafter defined) shall
                  occur with respect to Tenant; or

                  (vi)     A petition shall be filed against Tenant under any
                  law (other than the Bankruptcy Code) seeking any
                  reorganization, arrangement, composition, readjustment,
                  liquidation, dissolution, or similar relief under any present
                  or future Federal, State or other statute, law or regulation
                  and shall remain undismissed or unstayed for an aggregate of
                  ninety (90) days (whether or not consecutive), or if any
                  trustee, conservator, receiver or liquidator of Tenant or of
                  all or any substantial part of its properties shall be
                  appointed without the consent or acquiescence of Tenant and
                  such appointment shall remain unvacated or unstayed for an
                  aggregate of ninety (90) days (whether or not consecutive); or

                  (vii)    Tenant shall default in the performance or observance
                  of any covenant contained in Section 14.17 of the Lease;

         then in any such case Landlord may terminate this Lease by notice to
         Tenant, specifying a date not less than five (5) Business Days after
         the giving of such notice on which this Lease shall terminate, and this
         Lease shall come to an end on the date specified therein as fully and
         completely as if such date were the date herein originally fixed for
         the expiration of the Lease Term, and Tenant will then quit and
         surrender the Premises to Landlord, but Tenant shall remain liable as
         hereinafter provided.

         (b)      For purposes of clause (a)(v) above, an "Event of Bankruptcy"
         means the filing of a voluntary petition by Tenant, or the entry of an
         order for relief against Tenant, under Chapter 7, 11, or 13 of the
         Bankruptcy Code, and the term "Bankruptcy Code" means 11 U.S.C
         Section 101, et seq., If an Event of Bankruptcy occurs, then the
         trustee of Tenant's bankruptcy estate or Tenant as debtor-in-possession
         may (subject to final approval of the court) assume this Lease, and may
         subsequently assign it, only if it does the following within sixty (60)
         days after the date of the filing of the voluntary petition, the entry
         of the order for relief (or such additional time as a court of
         competent jurisdiction may grant, for cause, upon a motion made within
         the original 60-day period):

                  (i)      files a motion to assume the Lease with the
                           appropriate court;

                  (ii)     satisfies all of the following conditions, which
                           Landlord and Tenant acknowledge to be commercially
                           reasonable:

                           (A)      cures all Defaults of Tenant under this
                                    Lease or provides Landlord with Adequate
                                    Assurance (as defined below) that it will
                                    (y) cure all monetary Defaults of Tenant
                                    hereunder within ten (10) days from the date
                                    of the assumption; and (z) cures all
                                    non-monetary Defaults of Tenant hereunder
                                    within thirty (30) days from the date of the
                                    assumption;

                                      -40-
<PAGE>

                           (B)      compensates Landlord and any other person or
                                    entity, or provides Landlord with Adequate
                                    Assurance that within ten (10) days after
                                    the date of the assumption, it will
                                    compensate Landlord and such other person or
                                    entity for any pecuniary loss that Landlord
                                    and such other person or entity incurred as
                                    a result of any Default of Tenant, the
                                    trustee, or the debtor-in-possession;

                           (C)      provides Landlord with Adequate Assurance of
                                    Future Performance (as defined below) of all
                                    of Tenant's obligations under this Lease;
                                    and

                           (D)      delivers to Landlord a written statement
                                    that the conditions herein have been
                                    satisfied.

         (c)      For purposes only of the foregoing paragraph (b), and in
         addition to any other requirements under the Bankruptcy Code, any
         future federal bankruptcy law and applicable case law, "Adequate
         Assurance" means at least meeting the following conditions, which
         Landlord and Tenant acknowledge to be commercially reasonable:

                  (i)      entering an order segregating sufficient cash to pay
                           Landlord and any other person or entity under
                           paragraph (b) above, and

                  (ii)     granting to Landlord a valid lien and security
                           interest (in form acceptable to Landlord) in all
                           property comprising the Tenant's "property of the
                           estate," as that term is defined in Section 541 of
                           the Bankruptcy Code, which lien and security interest
                           secures the trustee's or debtor-in-possession's
                           obligation to cure the monetary and non-monetary
                           defaults under the Lease within the periods set forth
                           in paragraph (b) above.

         (d)      For purposes only of paragraph (b), and in addition to any
         other requirements under the Bankruptcy Code, any future federal
         bankruptcy law and applicable case law, "Adequate Assurance of Future.
         Performance" means at least meeting the following conditions, which
         Landlord and Tenant acknowledge to be commercially reasonable:

                  (i)      the trustee or debtor-in-possession depositing with
                           Landlord, as security for the timely payment of rent
                           and other monetary obligations, an amount equal to
                           the sum of two (2) months' Basic Rent plus an amount
                           equal to two (2) months' installments on account of
                           Taxes and Operating Expenses, computed in accordance
                           with Articles 8 and 9;

                  (ii)     the trustee or the debtor-in-possession agreeing to
                           pay in advance, on each day that the Basic Rent is
                           payable, the monthly installments on account of Taxes
                           and Operating Expenses, computed in accordance with
                           Articles 8 and 9 hereof;

                  (iii)    the trustee or debtor-in-possession providing
                           adequate assurance of the source of the rent and
                           other consideration due under this Lease; and

                  (iv)     Tenant's bankruptcy estate and the trustee or
                           debtor-in-possession providing Adequate Assurance
                           that the bankruptcy estate (and any successor after
                           the conclusion of the Tenant's bankruptcy
                           proceedings) will continue to have sufficient
                           unencumbered assets after the payment of all secured
                           obligations and administrative expenses to assure
                           Landlord

                                      -41-
<PAGE>

                           that the bankruptcy estate (and any successor after
                           the conclusion of the Tenant's bankruptcy
                           proceedings) will have sufficient funds to fulfill
                           Tenant's obligations hereunder.

         (e)      If the trustee or the debtor-in-possession assumes the Lease
         under paragraph (b) above and applicable bankruptcy law, it may assign
         its interest in this Lease only if the proposed assignee first provides
         Landlord with Adequate Assurance of Future Performance of all of
         Tenant's obligations under the Lease, and if Landlord determines, in
         the exercise of its reasonable business judgment, that the assignment
         of this Lease will not breach any other lease, or any mortgage,
         financing agreement, or other agreement relating to the Property by
         which Landlord or the Property is then bound (and Landlord shall not be
         required to obtain consents or waivers from any third party required
         under any lease, mortgage, financing agreement, or other such agreement
         by which Landlord is then bound).

         (f)      For purposes only of paragraph (e) above, and in addition to
         any other requirements under the Bankruptcy Code, any future federal
         bankruptcy law and applicable case law, "Adequate Assurance of Future
         Performance" means at least the satisfaction of the following
         conditions, which Landlord and Tenant acknowledge to be commercially
         reasonable:

                  (i)      the proposed assignee submitting a current financial
                           statement, audited by a certified public accountant,
                           that allows a net worth and working capital in
                           amounts determined in the reasonable business
                           judgment of Landlord to be sufficient to assure the
                           future performance by the assignee of Tenant's
                           obligation under this Lease; or

                  (ii)     if requested by Landlord in the exercise of its
                           reasonable business judgment, the proposed assignee
                           obtaining a guarantee (in form and substance
                           satisfactory to Landlord) from one or more persons
                           who satisfy Landlord's standards of creditworthiness;

         (g)      If this Lease shall have been terminated as provided in this
         Article, or if any execution or attachment shall be issued against
         Tenant or any of Tenant's property whereupon the Premises shall be
         taken or occupied by someone other than Tenant, then Landlord may
         re-enter the Premises, either by summary proceedings, ejectment or
         otherwise, and remove and dispossess Tenant and all other persons and
         any and all property from the same, as if this Lease had not been made.

         (h)      In the event of any termination, Tenant shall pay the Basic
         Rent, Additional Charges and other sums payable hereunder up to the
         time of such termination, and thereafter Tenant, until the end of what
         would have been the Lease Term in the absence of such termination, and
         whether or not the Premises shall have been relet, shall be liable to
         Landlord for, and shall pay to Landlord, as liquidated current damages,
         the Basic Rent, Additional Charges and other sums that would be payable
         hereunder if such termination had not occurred, less the net proceeds,
         if any, of any reletting of the Premises, after deducting all expenses
         in connection with such reletting, including, without limitation, all
         repossession costs, brokerage commissions, legal expenses, attorneys'
         fees, advertising, expenses of employees, alteration costs and expenses
         of preparation for such reletting. Tenant shall pay the portion of such
         current damages referred to above to Landlord monthly on the days which
         the Basic Rent would have been payable hereunder if this Lease had not
         been terminated.

                                      -42-
<PAGE>

         (i)      At any time after such termination, whether or not Landlord
         shall have collected any such current damages, as liquidated final
         damages and in lieu of all such current damages beyond the date of such
         demand, at Landlord's election Tenant shall pay to Landlord an amount
         equal to the excess, if any, of the Basic Rent, Additional Charges and
         other sums as hereinbefore provided which would be payable hereunder
         from the date of such demand (assuming that, for the purposes of this
         paragraph, annual payments by Tenant on account of Taxes and Operating
         Expenses would be the same as the payments required for the immediately
         preceding Operating or Tax Year for what would be the then unexpired
         Lease Term if the same remained in effect), over the then fair net
         rental value of the Premises for the same period, such difference being
         discounted at the rate of United States Treasury securities maturing as
         close as possible to the unexpired Lease Term if the same remained in
         effect plus fifty (50) basis points per annum to the then present
         value.

         (j)      In case of any Default by Tenant, re-entry, expiration and
         dispossession by summary proceedings or otherwise, Landlord may (i)
         re-let the Premises or any part or parts thereof, either in the name of
         Landlord or otherwise, for a term or terms which may at Landlord's
         option be equal to or less than or exceed the period which would
         otherwise have constituted the balance of the Lease Term and may grant
         concessions or free rent to the extent that Landlord considers
         advisable and necessary to re-let the same and (ii) may make such
         reasonable alterations, repairs and decorations in the Premises as
         Landlord in its sole judgment considers advisable and necessary for the
         purpose of reletting the Premises; and the making of such alterations,
         repairs and decorations shall not operate or be construed to release
         Tenant from liability hereunder as aforesaid. Landlord shall in no
         event be liable in any way whatsoever for failure to re-let the
         Premises, or, in the event that the Premises are re-let, for failure to
         collect the rent under such re-letting. Tenant hereby expressly waives
         any and all rights of redemption granted by or under any present or
         future laws in the event of Tenant being evicted or dispossessed, or in
         the event of Landlord obtaining possession of the Premises, by reason
         of the violation by Tenant of any of the covenants and conditions of
         this Lease.

         (k)      If a Guarantor of this Lease is named in Section 1.2, the
         happening of any of the events described in paragraphs (a)(iv)-(a)(vi)
         of this Section 13.1 with respect to the Guarantor shall constitute a
         Default of Tenant hereunder.

         (l)      The specified remedies to which Landlord may resort hereunder
         are not intended to be exclusive of any remedies or means of redress to
         which Landlord may at any time be entitled lawfully, and Landlord may
         invoke any remedy (including the remedy of specific performance)
         allowed at law or in equity as if specific remedies were not herein
         provided for.

         (m)      All reasonable costs and expenses incurred by or on behalf of
         Landlord (including, without limitation, attorneys' fees and expenses
         at both the trial and appellate levels) in enforcing its rights
         hereunder or occasioned by any Default of Tenant shall be paid by
         Tenant.

13.2     LANDLORD'S DEFAULT. Except as otherwise provided herein, Landlord shall
         in no event be in default in the performance of any of Landlord's
         obligations hereunder unless and until Landlord shall have failed to
         perform such obligations within thirty (30) days, or if such failure is
         of such a nature that Landlord cannot reasonably remedy the same within
         such thirty (30) day period, Landlord shall fail to commence promptly
         (and in any event within such thirty (30) day period) to remedy the
         same and to prosecute such remedy to completion with diligence and
         continuity.

                                      -43-
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                                   ARTICLE 14
                            MISCELLANEOUS PROVISIONS

14.1     EXTRA HAZARDOUS USE. Tenant covenants and agrees that Tenant will not
         do or permit anything to be done in or upon the Premises, or bring in
         anything or keep anything therein, which shall increase the rate of
         property or liability insurance on the Premises or the Property above
         the standard rate applicable to Premises being occupied for Permitted
         Uses; and Tenant further agrees that, in the event that Tenant shall do
         any of the foregoing, Tenant will promptly pay to Landlord, on demand,
         any such increase resulting therefrom, which shall be due and payable
         as an additional charge hereunder.

14.2     WAIVER. (a) Failure on the part of Landlord or Tenant to complain of
         any action or non- action on the part of the other, no matter how long
         the same may continue, shall never be a waiver by Tenant or Landlord,
         respectively, of any of the other's rights hereunder. Further, no
         waiver at any time of any of the provisions hereof by Landlord or
         Tenant shall be construed as a waiver of any of the other provisions
         hereof, and a waiver at any time of any of the provisions hereof shall
         not be construed as a waiver at any subsequent time of the same
         provisions. The consent or approval of Landlord or Tenant to or of any
         action by the other requiring such consent or approval shall not be
         construed to waive or render unnecessary Landlord's or Tenant's consent
         or approval to or of any subsequent similar act by the other.

         (b)      No payment by Tenant, or acceptance by Landlord, of a lesser
         amount than shall be due from Tenant to Landlord shall be treated
         otherwise than as a payment on account of the earliest installment of
         any payment due from Tenant under the provisions hereof. The acceptance
         by Landlord of a check for a lesser amount with an endorsement or
         statement thereon, or upon any letter accompanying such check, that
         such lesser amount is payment in full, shall be given no effect, and
         Landlord may accept such check without prejudice to any other rights or
         remedies which Landlord may have against Tenant.

14.3     COVENANT OF ENJOYMENT. Tenant, subject to the terms and provisions of
         this Lease, on payment of the Basic Rent and Additional Charges and
         observing, keeping and performing all of the other terms and provisions
         of this Lease on Tenant's part to be observed, kept and performed,
         shall lawfully, peaceably and quietly have, hold, occupy and enjoy the
         Premises during the Lease Term hereof, without hindrance or ejection by
         any persons lawfully claiming under Landlord to have title to the
         Premises superior to Tenant; the foregoing covenant of quiet enjoyment
         is in lieu of any other covenant, express or implied.

14.4     LANDLORD'S LIABILITY. (a) Tenant specifically agrees to look solely to
         Landlord's then equity interest in the Property at the time owned, for
         recovery of any judgment from Landlord; it being specifically agreed
         that Landlord (original or successor) shall never be personally liable
         for any such judgment, or for the payment of any monetary obligation to
         Tenant. The provision contained in the foregoing sentence is not
         intended to, and shall not, limit any right that Tenant might otherwise
         have to obtain injunctive relief against Landlord or Landlord's
         successors in interest, or to take any action not involving the
         personal liability of Landlord (original or successor) to respond in
         monetary damages from Landlord's assets other than Landlord's equity
         interest in the Property.

                                      -44-
<PAGE>

         (b)      Except as otherwise provided herein, with respect to any
         services or utilities to be furnished by Landlord to Tenant, Landlord
         shall in no event be liable for failure to furnish the same when
         prevented from doing so by strike, lockout, breakdown, accident, order
         or regulation of or by any governmental authority, or failure of
         supply, or failure whenever and for so long as may be necessary by
         reason of the making of repairs or changes which Landlord is required
         or is permitted by this Lease or by law to make or in good faith deems
         necessary, or inability by the exercise of reasonable diligence to
         obtain supplies, parts or employees necessary to furnish such services,
         or because of war or other emergency, or for any other cause beyond
         Landlord's reasonable control, or for any cause due to any act or
         neglect of Tenant or Tenant's contractors, agents, employees, licensees
         or any person claiming by, through or under Tenant, nor shall any such
         failure give rise to any claim in Tenant's favor that Tenant has been
         evicted, either constructively or actually, partially or wholly,
         provided Landlord shall use reasonable efforts to minimize interference
         with Tenant's business.

         (c)      In no event shall Landlord ever be liable to Tenant for any
         loss of business or any other indirect or consequential damages
         suffered by Tenant from whatever cause.

         (d)      Where provision is made in this Lease for Landlord's consent
         and Tenant shall request such consent and Landlord shall fail or refuse
         to give such consent, Tenant shall not be entitled to any damages for
         any withholding by Landlord of its consent, it being intended that
         Tenant's sole remedy shall be an action for specific performance or
         injunction, and that such remedy shall be available only in those cases
         where Landlord has expressly agreed in writing not to unreasonably
         withhold its consent. Furthermore, whenever Tenant requests Landlord's
         consent or approval (whether or not provided for herein), Tenant shall
         pay to Landlord, on demand, as Additional Charges, any expenses
         reasonably incurred by Landlord (including, without limitation, legal
         fees and costs, if any) in connection therewith.

14.5     NOTICE TO MORTGAGEE OR GROUND LESSOR. After receiving notice from any
         person, firm or other entity that it holds a mortgage or a ground lease
         which includes the Premises, no notice from Tenant to Landlord alleging
         any default by Landlord shall be effective unless and until a copy of
         the same is given to such holder or ground lessor (provided Tenant
         shall have been furnished with the name and address of such holder or
         ground lessor), and the curing of any of Landlord's defaults by such
         holder or ground lessor shall be treated as performance by Landlord.

14.6     ASSIGNMENT OF RENTS AND TRANSFER OF TITLE. (a) With reference to any
         assignment by Landlord of Landlord's interest in this Lease, or the
         rents payable hereunder, conditional in nature or otherwise, which
         assignment is made to the holder of a mortgage on property which
         includes the Premises, Tenant agrees that the execution thereof by
         Landlord, and the acceptance thereof by the holder of such mortgage,
         shall never be treated as an assumption by such holder of any of the
         obligations of Landlord hereunder unless such holder shall, by notice
         sent to Tenant, specifically otherwise elect and that, except as
         aforesaid, such holder shall be treated as having assumed Landlord's
         obligations hereunder only upon foreclosure of such holder's mortgage
         and the taking of possession of the Premises.

         (b)      In no event shall the acquisition of Landlord's interest in
         the Property by a purchaser which, simultaneously therewith, leases
         Landlord's entire interest in the Property back to the seller thereof
         be treated as an assumption by operation of law or otherwise, of
         Landlord's obligations hereunder, but Tenant shall look solely to such
         seller-lessee, and its successors from time to time in title, for
         performance of Landlord's

                                      -45-
<PAGE>

         obligations hereunder. In any such event, this Lease shall be subject
         and subordinate to the lease to such purchaser provided the
         purchaser-lessor executes a written agreement (substantially in the
         form annexed hereto as Exhibit H or such other form as may then be
         customarily used by such purchaser-lessor) that, subject to such
         reasonable qualifications as such purchaser-lessor may reasonably
         impose, in the event that the purchaser-lessor shall succeed to the
         interests of Landlord hereunder pursuant to such sale-leaseback
         arrangement, so long as no Default of Tenant exists hereunder, Tenant's
         right to possession of the Premises shall not be disturbed and Tenant's
         other rights hereunder shall not be adversely affected by any
         foreclosure of such encumbrance or by termination of such
         sale-leaseback arrangement and such purchaser-lessor shall assume
         Landlord's obligation under the Lease accruing after Landlord's
         foreclosure of its encumbrance or its taking of possession of the
         Premises for the purpose of foreclosing. For all purposes, such
         seller-lessee, and its successors in title, shall be the Landlord
         hereunder unless and until Landlord's position shall have been assumed
         by such purchaser-lessor.

         (c)      Except as provided in paragraph (b) of this Section, in the
         event of any transfer of title to the Property by Landlord, Landlord
         shall thereafter be entirely freed and relieved from the performance
         and observance of all covenants and obligations hereunder.

14.7     RULES AND REGULATIONS. Tenant shall abide by reasonable rules and
         regulations from time to time established by Landlord ("Rules and
         Regulations"), it being agreed that such Rules and Regulations will be
         established and applied by Landlord in a non-discriminatory fashion,
         such that all Rules and Regulations shall be generally applicable to
         other tenants, of similar nature to the Tenant named herein, of the
         Building. Landlord agrees to use reasonable efforts to insure that any
         such Rules and Regulations are uniformly enforced, but Landlord shall
         not be liable to Tenant for violation of the same by any other tenant
         or occupant of the Building, or persons having business with them. In
         the event that there shall be a conflict between such Rules and
         Regulations and the provisions of this Lease, the provisions of this
         Lease shall control. Rules and Regulations currently in effect are set
         forth in Exhibit F hereto.

14.8     ADDITIONAL CHARGES. If Tenant shall fail to pay when due any sums under
         this Lease designated as Additional Charges, Landlord shall have the
         same rights and remedies as Landlord has hereunder for failure to pay
         Basic Rent.

14.9     INVALIDITY OF PARTICULAR PROVISIONS. If any term or provision of this
         Lease, or the application thereof to any person or circumstance shall,
         to any extent, be invalid or unenforceable, the remainder of this
         Lease, or the application of such term or provision to persons or
         circumstances other than those as to which it is held invalid or
         unenforceable, shall not be affected thereby, and each term and
         provision of this Lease shall be valid and be enforced to the fullest
         extent permitted by law.

14.10    PROVISIONS BINDING ETC. Except as herein otherwise provided, the terms
         hereof shall be binding upon and shall inure to the benefit of the
         successors and assigns, respectively, of Landlord and Tenant (except in
         the case of Tenant, only, such assigns as may be permitted hereunder)
         and, if Tenant shall be an individual, upon and to his heirs,
         executors, administrators, successors and permitted assigns. The
         reference contained to successors and assigns of Tenant is not intended
         to constitute a consent to assignment by Tenant, but has reference only
         to those instances in which Landlord has later given consent to a
         particular assignment as required by those provisions of Article 6
         hereof.

                                      -46-
<PAGE>

14.11    RECORDING. Tenant agrees not to record this Lease, but, if the Lease
         Term (including any extended term) is seven (7) years or Longer, each
         party hereto agrees, on the request of the other, to execute a
         so-called notice of lease in recordable form and complying with
         applicable law and reasonably satisfactory to Landlord's attorneys. In
         no event shall such document set forth the rent or other charges
         payable by Tenant under this Lease; and any such document shall
         expressly state that it is executed pursuant to the provisions
         contained in this Lease, and is not intended to vary the terms and
         conditions of this Lease.

14.12    NOTICES. Whenever, by the terms of this Lease, notices shall or may be
         given either to Landlord or to Tenant, such notice shall be in writing
         and shall be sent by registered or certified mail, postage prepaid,
         return receipt requested or by a nationally recognized overnight
         courier service (next Business Day delivery):

         If intended for Landlord, addressed to Landlord at Landlord's Original
         Address and marked: "Attention: Asset Manager, " with a copy to Peter
         Van, Esq., Bingham Dana LLP, 150 Federal Street, Boston, MA 02110 (or
         to such other address or addresses as may from time to time hereafter
         be designated by Landlord by like notice), provided that Tenant shall
         have no liability for, and the notice given to Landlord shall not be
         defective by reason of, the failure to give such notice to Landlord's
         counsel.

         If intended for Tenant, addressed to Tenant at Tenant's Original
         Address until the Commencement Date and thereafter to the Premises (or
         to such other address or addresses as may from time to time hereafter
         be designated by Tenant by like notice), and to BMC Software, Inc.,
         2101 City West Blvd., 20th FL., Houston, TX 77042, Attention: Mark D.
         Taylor, with a courtesy copy to (a) Gray H. Muzzy, Bracewell &
         Patterson, L.L.P., 711 Louisiana, Suite 2900, Houston, TX 77002 and (b)
         Broker, provided that Landlord shall have no liability for, and the
         notice given to Tenant shall not be defective by reason of, the failure
         to give such notice to Tenant's counsel or Broker with the exception of
         notices pursuant to Exhibit P in which case all the foregoing notices
         shall be required in order to be effective.

         All such notices shall be effective upon the sooner of receipt or first
         attempted delivery when deposited in the United States Mail within the
         Continental United States or with an overnight courier service,
         provided that the same are received in ordinary course at the address
         to which the same were sent.

14.13    WHEN LEASE BECOMES BINDING. The submission of this document for
         examination and negotiation does not constitute an offer to lease, or a
         reservation of, or option for, the Premises, and this document shall
         become effective and binding only upon the execution and delivery
         hereof by both Landlord and Tenant. All negotiations, considerations,
         representations and understandings between Landlord and Tenant are
         incorporated herein and this Lease expressly supersedes any proposals
         or other written documents relating hereto. This Lease may be modified
         or altered only by written agreement between Landlord and Tenant, and
         no act or omission of any employee or agent of Landlord shall alter,
         change or modify any of the provisions hereof.

14.14    PARAGRAPH HEADINGS AND INTERPRETATION OF SECTIONS. The paragraph
         headings throughout this instrument are for convenience and reference
         only, and the words contained therein shall in no way be held to
         explain, modify, amplify or aid in the interpretation, construction or
         meaning of the provisions of this Lease. The provisions of this Lease
         shall be construed as a whole, according to their common meaning
         (except

                                      -47-

<PAGE>

         where a precise legal interpretation is clearly evidenced), and not for
         or against either party. Use in this Lease of the words "including,"
         "such as" or words of similar import, when followed by any general
         term, statement or matter, shall not be construed to limit such term,
         statement or matter to the specified item(s), whether or not language
         of non-limitation, such as "without limitation" or "including, but not
         limited to," or words of similar import, are used with reference
         thereto, but rather shall be deemed to refer to all other terms or
         matters that could fall within a reasonably broad scope of such term,
         statement or matter. Use in this Lease of the words "not to be
         unreasonably withheld" or words of similar import shall be construed to
         mean "not to be unreasonably withheld, delayed or conditioned" unless
         the context clearly requires otherwise.

14.15    RIGHTS OF MORTGAGEE OR GROUND LESSOR. This Lease shall be subordinate
         to any mortgage or ground lease from time to time encumbering the
         Premises, whether executed and delivered prior to or subsequent to the
         date of this Lease, if the holder of such mortgage or ground lease
         shall so elect, provided that such holder enters into a written
         agreement (substantially in the form annexed hereto as Exhibit H or
         such other form as may then be customarily used by such holder) that,
         subject to such reasonable qualifications as such holder may reasonably
         impose, in the event that the holder shall succeed to the interests of
         Landlord hereunder pursuant to such mortgage, ground lease or other
         encumbrance, so long as no Default of Tenant exists hereunder, Tenant's
         right to possession of the Premises shall not be disturbed and Tenant's
         other rights hereunder shall not be adversely affected by any
         foreclosure of such mortgage or encumbrance or by termination of such
         ground lease and such holder shall assume Landlord's obligation under
         the Lease accruing after Landlord's foreclosure of its mortgage or its
         taking of possession of the Premises for the purpose of foreclosing. If
         this Lease is subordinate to any mortgage or ground lease and the
         holder thereof (or successor) shall succeed to the interest of
         Landlord, at the election of such holder (or successor) Tenant shall
         attorn to such holder and this Lease shall continue in full force and
         effect between such holder (or successor) and Tenant. Tenant agrees to
         execute such instruments of subordination or attornment in confirmation
         of the foregoing agreement as such holder may reasonably request.
         Notwithstanding anything contained herein to the contrary, Tenant's
         obligation to pay Basic Rent or any Additional Charges is conditioned
         upon the receipt by Tenant of a fully executed Lease Subordination,
         Non-Disturbance of Possession and Attornment Agreement ("SNDA") from
         each of Landlord's lenders in substantially the form of Exhibit H
         hereto. If, on or prior to the Commencement Date hereof, an SNDA shall
         not have been executed by any of Landlord's lenders, Tenant may
         terminate this Lease by notice to Landlord, specifying a date not
         sooner than ninety (90) days after the giving of such notice on which
         this Lease shall terminate, and if prior to such termination date set
         forth in Tenant's notice each of Landlord's lenders have not executed
         and delivered to Tenant an SNDA previously executed by Tenant, then
         this Lease shall come to an end on the date specified in Tenant's
         notice as fully and completely as if such were the date herein
         originally fixed for the expiration of the Lease Term, whereupon Tenant
         will vacate and surrender the Premises to Landlord.

14.16    STATUS REPORT. Recognizing that both parties may find it necessary to
         establish to third parties such as accountants, banks, mortgagees,
         ground lessors, or the like, the then current status of performance
         hereunder, either party, on the request of the other made from time to
         time, will promptly furnish to Landlord, or the holder of any mortgage
         or ground lease encumbering Premises, or to Tenant, as the case may be,
         a statement of the status of any matter pertaining to this Lease,
         including, without limitation, acknowledgments that (or the extent to
         which) each party is in compliance with its obligations under the terms
         of this Lease.

                                      -48-

<PAGE>

14.17    SECURITY DEPOSIT. In the event that at any time during the Lease Term,
         the Guarantor merges or consolidates with any other entity or sells,
         transfers or otherwise disposes of a material portion of Guarantor's
         assets (a "Capital Event") and any such Capital Event results in a
         sixty percent (60%) or more reduction in the net worth of the Guarantor
         or its successor entity computed in accordance with generally accepting
         accounting principles consistently applied from the net worth of the
         Guarantor immediately prior to such Capital Event (a "Security Deposit
         Event"), Tenant shall immediately notify the Landlord of the occurrence
         of the Security Deposit Event and Tenant shall, within forty-five (45)
         days of the date of the Security Deposit Event, provide Landlord with a
         security deposit (the "Security Deposit") based on the following
         schedule:

         Period in which                                        Amount of
         Security Deposit                                       Required
         Event Occurs                                           Security
                                                                 Deposit
                                                               (number of
                                                             months of then
                                                              payable Basic
                                                           Rent multiplied by
                                                                Premises
                                                              Rentable Area
                                                                including
                                                                expansion
                                                             space, if any,
                                                           on the calculation
                                                                 date)

<TABLE>
<CAPTION>
                                 If Market                     If Market
                           Capitalization is less      Capitalization is greater
                            than $2,000,000,000           than $2,000,000,000
                            -------------------           -------------------
<S>                        <C>                         <C>
From execution date                3                               0
of Lease to last day of
month in which
occurs the fifth
anniversary of the
Commencement Date

For next 60 months                 2                               0
(years 6-10)

Extension Term                     1                               0
(years 11-20)
</TABLE>

         For purposes hereof, "Market Capitalization" shall mean the then
         outstanding number of shares of the Guarantor or its successor entity
         multiplied by the average stock price of such shares for the thirty
         (30) day period succeeding the Security Deposit Event.

                                      -49-

<PAGE>

         Landlord shall hold the Security Deposit throughout the Lease Term, as
         such may be extended, as security for the performance by Tenant of all
         obligations on the part of Tenant hereunder. The Security Deposit shall
         be delivered to Landlord by Tenant at Tenant's expense and shall be in
         the form of a clean, irrevocable Letter of Credit issued by and drawn
         upon any commercial bank reasonably acceptable to Landlord with a
         banking office in Boston (hereinafter referred to as the "Issuing
         Bank") which Letter of Credit shall (i) name Landlord as beneficiary
         thereof, (ii) have a term of not less than one (1) year, (iii) be in
         the applicable amount based on the schedule set forth above, and (iv)
         otherwise be in form and content reasonably satisfactory to Landlord.
         The Letter of Credit shall, in any event, provide that:

                           (1)      The Issuing Bank shall pay to Landlord an
         amount up to the face amount of the Letter of Credit upon presentation
         of a statement that a Default of Tenant has occurred, specifying the
         nature of such Default and a demand for payment in the amount to be
         drawn and notice of such presentation shall be delivered simultaneously
         to Tenant;

                           (2)      The Letter of Credit shall be deemed to be
         automatically renewed, without amendment, for consecutive periods of
         one year each and shall have a final expiry date of not earlier than
         thirty (30) days after the expiration of the Lease Term, unless the
         Issuing Bank sends written notice (hereinafter called the "Non-Renewal
         Notice") to Landlord both by Federal Express or another recognized
         national or regional courier and by certified or registered mail,
         return receipt requested, not less than sixty (60) days next preceding
         the then expiration date of the Letter of Credit, that it elects not to
         have such Letter of Credit renewed;

                           (3)      Landlord, after receipt of the Non-Renewal
         Notice, or within sixty (60) days prior to the expiration date of any
         Letter of Credit then held by Landlord, shall have the right,
         exercisable by a demand for payment draft only, to draw upon the Letter
         of Credit and receive the proceeds thereof (which shall be held by
         Landlord as a cash deposit pursuant to the terms of this Section 14.17
         pending the replacement of such Letter of Credit or applied as
         permitted by the terms of this Section 14.17); and

                           (4)      Upon Landlord's sale or other transfer of
         the Building, or Landlord's interest therein, or a leasing of the
         Building, the Letter of Credit shall be transferable by Landlord and
         Landlord shall thereupon be released by Tenant from all liability for
         the return of such Letter of Credit. In such event, Tenant agrees to
         look solely to the new Landlord for the return of said Letter of
         Credit, Tenant shall execute such documents as may be necessary to
         accomplish such transfer or assignment of the Letter of Credit.
         Landlord shall pay any transfer fees of the Issuing Bank.

         Tenant covenants that it will not assign or encumber, or attempt to
         assign or encumber, the Letter of Credit or proceeds thereof, and that
         neither Landlord nor its successors or assigns shall be bound by any
         such assignment, encumbrance, attempted assignment, or attempted
         encumbrance. If Landlord determines, in its reasonable discretion, that
         the financial condition of the Issuing Bank has so declined as to cause
         concern that the Issuing Bank may not honor a draw on its Letter of
         Credit and provides Tenant with notice of the same, Tenant shall
         promptly obtain a replacement Letter of Credit complying with the terms
         hereof from another commercial bank acceptable to Landlord.

         Landlord shall, without prejudice to any other remedy Landlord may have
         on account thereof, apply the proceeds of the Letter of Credit, or any
         part thereof, to Landlord's damages arising from, or to cure, any
         Default of Tenant. Upon the application of such

                                      -50-

<PAGE>

         proceeds, Tenant shall promptly deposit with Landlord the amount
         applied to be held as security here under or obtain a replacement
         Letter of Credit in such amount conforming with the other requirements
         of this Section 14.17. Provided no Default of Tenant then exists or
         such Default has been waived in writing by Landlord, then the Letter of
         Credit shall be reduced on the dates set forth in the above schedule to
         the applicable amount specified thereon based on the Guarantor's then
         Market Capitalization by delivery by Tenant to Landlord of a substitute
         Letter of Credit, it being understood that Landlord shall not be
         obligated to return any Letter of Credit in its possession until Tenant
         has delivered a substitute Letter of Credit, provided that Landlord
         shall immediately return to Tenant any Letter of Credit for which
         replacement or substitution has been made by Tenant in accordance with
         this Section 14.17.

         Provided that no Default of Tenant then exists or such Default has been
         waived in writing by Landlord, Landlord shall return the Letter of
         Credit, or so much thereof as shall have theretofore not been applied
         in accordance with the terms of this Section 14.17, to Tenant on the
         expiration or earlier termination of the Lease Term and surrender of
         possession of the Premises by Tenant to Landlord at such time. If
         Landlord conveys Landlord's interest under this Lease, the Letter of
         Credit, or any part thereof not previously applied, may be turned over
         by Landlord to Landlord's grantee, and, if so turned over, Tenant
         agrees to look solely to such grantee for proper application of the
         Letter of Credit in accordance with the terms of this Section 14.17,
         and the return thereof in accordance herewith. The holder of a mortgage
         shall not be responsible to Tenant for the return or application of any
         such Letter of Credit, whether or not it succeeds to the position of
         Landlord hereunder, unless such Letter of Credit shall have been
         received in hand by such holder.

14.18    REMEDYING DEFAULTS. Landlord shall have the right, but shall not be
         required, to pay such sums or do any act which requires the expenditure
         of monies which may be necessary or appropriate by reason of the
         failure or neglect of Tenant to perform any of the provisions of this
         Lease, and in the event of the exercise of such right by Landlord,
         Tenant agrees to pay to Landlord forthwith upon demand all such sums,
         together with interest thereon at a rate equal to two percent (2%) over
         the base rate in effect from time to time at Fleet National Bank, as an
         Additional Charge. Any payment of Basic Rent or Additional Charges not
         paid when due shall, at the option of Landlord, bear interest at a rate
         equal to two percent (2%) over the base rate in effect from time to
         time at Fleet National Bank from the due date thereof and shall be
         payable forthwith on demand by Landlord, as an Additional Charge.
         Interest on overdue payments of Basic Rent,'or Additional Charges shall
         cease to accrue at such time as an administrative fee with respect to
         such overdue payment has been charged to Tenant in accordance with
         Section 4.1, unless a Default of Tenant continues beyond applicable
         cure and notice periods, in which case interest on overdue payments
         shall accrue retroactively to the date such payment was first due.

14.19    HOLDING OVER. Any holding over by Tenant after the expiration of the
         Lease Term shall be treated as a daily tenancy at sufferance at a rate
         equal to (i) one and one-half (1 1/2) times the Basic Rent then in
         effect plus (ii) Additional Charges and other charges herein provided
         (prorated on a daily basis). Tenant shall also pay to Landlord all
         damages, direct and/or indirect, sustained by reason of any such
         holding over. Otherwise, such holding over shall be on the terms and
         conditions set forth in this Lease as far as applicable. Landlord
         agrees to use reasonable efforts to mitigate damages in the event of a
         holding over by Tenant, but any costs incurred by Landlord in
         connection with such efforts shall be borne by Tenant and payable
         immediately upon demand therefor.

                                      -51-

<PAGE>

14.20    SURRENDER OF PREMISES. Upon the expiration or earlier termination of
         the Lease Term, Tenant shall peaceably quit and surrender to Landlord
         the Premises in neat and clean condition and in good order, condition
         and repair, together with all Alterations which may have been made or
         installed in, on or to the Premises prior to or during the Lease Term,
         excepting only ordinary wear and use and damage by fire or other
         casualty. Tenant shall remove all of Tenant's Removable Property and,
         to the extent specified by Landlord, all Alterations made by Tenant and
         all partitions wholly within the Premises unless installed initially by
         Landlord in preparing the Premises for Tenant's occupancy; and shall
         repair any damage to the Premises or the Building caused by such
         removal. Any of Tenant's Removable Property which shall remain in the
         Building or on the Premises after the expiration or termination of the
         Lease Term shall be deemed conclusively to have been abandoned, and
         either may be retained by Landlord as its property or may be disposed
         of in such manner as Landlord may see fit, at Tenant's sole cost and
         expense.

14.21    BROKERAGE. Tenant warrants and represents that Tenant has dealt with no
         broker in connection with the consummation of this Lease other than
         Broker, and, in the event of any brokerage claims against Landlord
         predicated upon prior dealings with Tenant, Tenant agrees to defend the
         same and indemnify Landlord against any such claim (except any claim by
         Broker who shall be paid by Landlord).

14.22    GOVERNING LAW. This Lease shall be governed exclusively by the
         provisions hereof and by the laws of the Commonwealth of Massachusetts
         as the same may from time to time exist.

14.23    FINANCIAL STATEMENTS. Tenant shall furnish the Landlord as soon as
         available but in any event within (a) ninety (90) days after the end of
         each fiscal year of Guarantor the audited consolidated financial
         statements for the Guarantor as of the end of such fiscal year and (b)
         within forty-five (45) days after the end of each of the first three
         fiscal quarters in any fiscal year of Guarantor, an unaudited
         consolidated balance sheet for the Guarantor as at the end of such
         quarter, and an unaudited consolidated statement of income and
         statement of changes in financial position of Guarantor for the period
         commencing with the end of the preceding fiscal year and ending with
         the end of such quarter, together with a certificate of the chief
         financial officer of the Guarantor stating that such financial
         statements fairly present the financial condition of the Guarantor as
         of the date thereof, all of which shall be prepared in accordance with
         generally accepted accounting principles consistently applied.

14.24    YEAR 2000. Landlord represents to Tenant that it (a) has initiated a
         review and assessment of all areas within its and its respective
         affiliates' businesses and operation (including those affected by their
         respective suppliers and vendors) that could be adversely affected by
         the Year 2000 Problem (hereinafter defined), (b) has developed a plan
         and timeline for addressing the Year 2000 Problem on a timely basis and
         is following such plan and timetable, (c) has no reason to believe that
         any of its and its respective affiliates' businesses or operations
         (including those affected by their respective suppliers and vendors)
         related to the ownership, management, operation and maintenance of the
         Building will be adversely impacted by the Year 2000 Problem, and (d)
         it and its affiliates' are, or by December 31, 1998 will be, Year 2000
         Compliant (hereinafter defined). "Year 2000 Problem" means the risk
         that computer applications used by Landlord and its affiliates (and
         their respective suppliers or vendors) may be unable to recognize or
         properly perform date-sensitive functions involving certain dates prior
         to, or any date after, December 31, 1999. "Year 2000 Compliant" means
         that all

                                      -52-

<PAGE>

         computer applications used by Landlord and its affiliates related to
         the ownership, management, operation and maintenance of the Building
         are able to avoid the Year 2000 Problem.

                                   ARTICLE 15

                               OPTIONS TO EXTEND

15.1     TENANT'S RIGHT. Provided that, at the time of each such exercise, (i)
         there exists no Default of Tenant; (ii) this Lease is still in full
         force and effect; and (iii) Tenant actually occupies at least
         seventy-five percent (75%) of Premises Rentable Area, Tenant shall have
         the option to extend the Term of this Lease as to the Premises
         originally leased hereunder, as such may have been expanded pursuant to
         Article 17 or Article 18 hereof, for up to three (3) consecutive
         extended terms (individually an "Extended Term" and, collectively, the
         "Extended Terms"), each having a minimum length of five (5) years, and
         which Extended Terms shall not exceed a term of fifteen (15) years in
         the aggregate. The length of the applicable Extended Term (but not less
         than five (5) years) shall be designated by Tenant to Landlord at the
         time Tenant first notifies Landlord of its interest to extend as
         provided below. Tenant shall exercise each such option by giving
         Landlord notice of its interest to do so, not later than fourteen (14)
         months prior to the expiration of the initial Lease Term or Extended
         Term, as applicable, it being agreed that time shall be of the essence
         with respect to the giving of such notice. Landlord shall, within
         forty-five (45) days of receipt of Tenant's notice of interest, provide
         Tenant with notice of its determination of Fair Market Rental Value for
         the applicable Extended Term. Within forty-five (45) days of receipt of
         Landlord's Fair Market Rental Value determination, Tenant shall elect
         either (i) not to extend the term of this Lease for the Extended Term,
         (ii) to accept Landlord's determination of Fair Market Rental Value and
         extend the term of this Lease for the Extended Term; or (iii) to extend
         the term of this Lease for the Extended Term and provide Landlord with
         notice of its determination of Fair Market Rental Value for the
         applicable Extended Term, whereupon the determination of Fair Market
         Rental Value shall be submitted to the process set forth in Article 16.
         Each of Landlord's and Tenant's notice to the other setting forth their
         respective determinations of Fair Market Rental Value for the
         applicable Extended Term is hereinafter referred to as a "Determination
         Notice. In the event that Tenant fails to give such notice of interest
         to Landlord or declines to extend the Lease Term, the term of this
         Lease shall automatically terminate at the end of the initial Lease
         Term or the then applicable Extended Term, and Tenant shall have no
         further right or option to extend the term of this Lease. Each Extended
         Term shall commence on the day immediately following the expiration
         date of the initial Lease Term or the previous Extended Term, as the
         case may be, and shall end on the day designated in Tenant's notice to
         Landlord of its Extension Term election, and shall be on all the terms
         and conditions of this Lease, except that the Basic Rent for such
         Extended Term shall be determined in accordance with Section 15.2.

15.2     EXTENDED TERM RENT. The Basic Rent for each Extended Term shall be
         equal to the Fair Market Rental Value of the Premises (as hereinafter
         defined) as of the commencement of the then applicable Extended Term.
         In no event, however, shall the Basic Rent and Additional Charges for
         any Extended Term be less than the annual Basic Rent plus Additional
         Charges (on a Premises Rentable Area square footage basis) for the
         12-month period prior to the effective date of such Extended Term.

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<PAGE>

                                   ARTICLE 16

                            FAIR MARKET RENTAL VALUE

16.1     DEFINITION. (a) The term "Fair Market Rental Value" shall mean the
         annual fixed rent on the date on which such fixed rent will become
         effective (the "Determination Date") that is being negotiated in
         leases, or is reflected in leases which have been executed, in arm's
         length transactions between willing landlords and willing tenants, each
         acting in its own best interest and without duress using the same
         definitions of Base Taxes and Base Operating Expenses as used with
         respect to the initial Lease Term, for comparable space located in the
         Complex or at Bay Colony Corporate Center in Waltham, Massachusetts or
         any other comparable first class office properties, considering the
         points 1-10 below. If Landlord and Tenant shall fail to agree upon the
         Fair Market Rental Value within thirty (30) days after Tenant has given
         its Determination Notice to Landlord setting forth its determination of
         the Fair Market Rental Value, then, subject to the provisions of
         paragraph (b) below, Landlord or Tenant may apply to the American
         Arbitration Association or any successor thereto for the designation of
         an arbitrator to render a final determination of the Fair Market Rental
         Value. The arbitrator shall be a real estate appraiser or consultant
         who shall have at least ten (10) years' continuous experience as a
         commercial real estate broker or appraiser, and having significant
         experience with property similar to the Building in the greater Boston
         area and shall not be affiliated with Landlord or Tenant. The
         arbitrator shall conduct such hearings and investigations as the
         arbitrator shall deem appropriate to determine the Fair Market Rental
         Value and shall, within thirty (30) days after having been appointed,
         choose the determination set forth in either Landlord's or Tenant's
         Determination Notice, and that choice by the arbitrator shall be
         binding upon Landlord and Tenant. In determining Fair Market Rental
         Value, the parties and the arbitrator shall take into account factors
         such as (but not limited to) the following:

            1.    Size of Tenant.

            2.    Location, use, size and/or floor levels(s) of the space in
                  question, including view, elevator lobby exposure, etc.

            3.    Definition of "rentable" area.

            4.    Extent of leasehold improvements or allowances to be provided
                  on either new lease transactions or lease renewal
                  transactions, where applicable.

            5.    Inclusion of parking costs, if any.

            6.    Term or length of lease.

            7.    Base year costs associated with operating expenses and real
                  estate taxes.

            8.    The time the particular rental rate under consideration was
                  agreed upon and became or is to become effective.

            9.    Whether the transaction in question is a lease renewal, lease
                  expansion or lease extension.

            10.   Any other concession or inducement and/or relevant term or
                  condition in making such fair market value rental rate
                  determination.

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<PAGE>

                  Each party shall pay its own counsel fees and expenses, if
         any, in connection with any arbitration under this paragraph (a), and
         the parties shall share equally all other expenses and fees of any such
         arbitration. The determination rendered in accordance with the
         provisions of this paragraph (a) shall be final and binding in fixing
         the Fair Market Rental Value. The arbitrator shall not have the power
         to add to, modify, or change any of the provisions of this Lease.

         (b)      In the event that the determination of the Fair Market Rental
         Value set forth in the Landlord's and Tenant's Determination Notices
         shall differ by equal to or less than five percent (5%) per square foot
         of Premises Rentable Area per annum for each year for which the same is
         being determined, then the Fair Market Rental Value shall not be
         determined by arbitration, but shall instead be set by taking the
         average of the determinations set forth in Landlord's and Tenant's
         Determination Notices. Only if the determinations set forth in
         Landlord's and Tenant's Determination Notices shall differ by more than
         5% per square foot of Premises Rentable area per annum for any year for
         which the same is being determined shall the actual determination of
         Fair Market Rental Value be made by an arbitrator as set forth in
         paragraph (a) above.

         (c)      If for any reason the Fair Market Rental Value shall not have
         been determined prior to the Determination Date, then, until the Fair
         Market Rental Value and, accordingly, the Basic Rent, shall have been
         finally determined, Tenant shall pay Basic Rent at the rate quoted by
         Landlord in Landlord's Determination Notice. Upon final determination
         of the Fair Market Rental Value, an appropriate adjustment to the Basic
         Rent theretofore paid by Tenant from and after the Determination Date
         shall be made reflecting such final determination, and Landlord or
         Tenant, as the case may be, shall promptly credit or pay, respectively,
         to the other any overpayment or deficiency, as the case may be, in the
         payment of Basic Rent and Additional Charges from the Determination
         Date to the date of such final determination.

                                   ARTICLE 17

                               EXPANSION OPTIONS

17.1.    FIRST EXPANSION SPACE. For purposes of this Lease, the "First Expansion
         Space" shall mean any space in the Building or the building known and
         numbered as 890 Winter Street, Waltham, Massachusetts (the "890
         Building"), and shall comprise between 28,000 and 42,000 rentable
         square feet which is not then leased by Tenant. Landlord shall make the
         First Expansion Space available for occupancy by Tenant at a date.
         commencing between July 1, 2004 and September 30, 2005, Such space
         shall consist of not more than three (3) non-contiguous spaces of not
         less than 5,000 rentable square feet each.

         (a)      Provided that, at the time of the giving of "Tenant's First
         Expansion Notice" and as of the "First Expansion Space Inclusion Date"
         (as such terms are hereinafter defined), there exists no Default of
         Tenant and the Lease is still in full force and effect, Landlord shall
         offer to Tenant, subject to the provisions of this Article 17, the
         right to add such First Expansion Space to the Premises then demised
         pursuant to this Lease.

         (b)      The offer made by Landlord to Tenant shall be by a written
         notice (hereinafter called the "First Expansion Notice"), to be
         provided at least one year prior to the First Expansion Space Inclusion
         Date and shall specify the space being offered, the date such space
         shall become available for Tenant's occupancy (the "First Expansion
         Space

                                      -55-

<PAGE>

         Inclusion Date"), and Landlord's calculation of Fair Market Rental
         Value. Landlord shall provide Tenant with floor plans of the First
         Expansion Space (including as-built plans to the extent available) and
         afford Tenant a reasonable opportunity to view the First Expansion
         Space within fifteen (15) days of the delivery of the First Expansion
         Notice.

17.2.    TENANT'S FIRST EXPANSION NOTICE. (a)      Tenant may either (i) accept
         the offer set forth in the First Expansion Notice as set forth above or
         (ii) elect to lease the First Expansion Space and provide Landlord with
         its determination of Fair Market Rental Value for the First Expansion
         Space, whereupon the determination of Fair Market Rental Value for such
         space shall be submitted to the process set forth in Article 16, by
         delivering to Landlord a written notice (hereinafter called "Tenant's
         First Expansion Notice"), provided, in either case, Tenant's First
         Expansion Notice shall be delivered at least ten (10) months prior to
         the First Expansion Space Inclusion Date. The First Expansion Space so
         accepted by Tenant shall be added to and included in the Premises on
         the First Expansion Space Inclusion Date. Each of Landlord's and
         Tenant's notice to the other setting forth their respective
         determinations of Fair Market Rental Value for the First Expansion
         Space shall constitute each of Landlord's and Tenant's "Determination
         Notice" for purposes of Article 16.

         (b)      If Tenant does not give Tenant's First Expansion Notice (or
         fails to timely give Tenant's First Expansion Notice) pursuant to the
         provisions of this Article 17, time being of the essence, Landlord
         shall be under no further obligation with respect to the First
         Expansion Space (the "First Untaken Space") by reason of this Article
         17, and Tenant shall have waived and relinquished its right under this
         Article 17 to the First Untaken Space, and, subject to Article 18,
         Landlord shall at any and all times thereafter be entitled to lease the
         First Untaken Space to others at such rental and upon such terms and
         conditions as Landlord in its sole discretion may desire, whether such
         rental terms, provisions and conditions are the same as those offered
         to Tenant or more or less favorable.

17.3.    EFFECT OF INCLUSION. Provided that Tenant provides Landlord with
         Tenant's First Expansion Notice pursuant to Section 17.2, upon the
         First Expansion Space Inclusion Date, Landlord agrees to lease to
         Tenant and Tenant agrees to lease from Landlord the First Expansion
         Space for the remaining Lease Term. Upon the occurrence of the First
         Expansion Space Inclusion Date:

         (a)      the term "Premises" shall be deemed to include the First
         Expansion Space;

         (b)      the Premises Rentable Area shall be increased by the rentable
         area within the First Expansion Space, and Tenant's Proportionate Share
         shall be adjusted accordingly;

         (c)      the Basic Rent per annum (on an aggregate but not square
         footage basis) shall be increased by an amount equal to the Fair Market
         Rental Value for the First Expansion Space, which shall be determined
         in accordance with Article 16 hereof;

         (d)      Additional Charges shall thereafter be computed on the basis
         of the inclusion of the First Expansion Space into the Premises; and

         (e)      the term of this Lease with respect to the First Expansion
         Space shall be coterminous with the Lease Term.

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<PAGE>

17.4.    SECOND EXPANSION SPACE. For purposes of this Lease, the "Second
         Expansion Space" shall mean any space in the Building or the 890
         Building, and shall comprise between 28,000 and 42,000 rentable square
         feet which is not then leased by Tenant. Landlord shall make the Second
         Expansion Space available for occupancy by Tenant at a date commencing
         between July 1, 2006 and June 30, 2007. Such space shall consist of
         not more than three (3) non-contiguous spaces of not less than 5,000
         rentable square feet each.

         (a)      Provided that, at the time of the giving of "Tenant's Second
         Expansion Notice" and as of the "Second Expansion Space Inclusion Date"
         (as such terms are hereinafter defined), there exists no Default of
         Tenant and the Lease is still in full force and effect, Landlord shall
         offer to Tenant, subject to the provisions of this Article 17, the
         right to add such Second Expansion Space to the Premises then demised
         pursuant to this Lease.

         (b)      The offer made by Landlord to Tenant shall be by a written
         notice (hereinafter called the "Second Expansion Notice"), to be
         provided at least one year prior to the Second Expansion Space
         Inclusion Date and shall specify the space being offered, the date such
         space shall become available for Tenant's occupancy (the "Second
         Expansion Space Inclusion Date"), and Landlord's calculation of Fair
         Market Rental Value. Landlord shall provide Tenant with floor plans of
         the Second Expansion Space (including as-built plans of the Second
         Expansion Space to the extent available) and afford Tenant a reasonable
         opportunity to view the Second Expansion space within fifteen (15) days
         of the delivery of the Second Expansion Notice.

17.5.    TENANT'S SECOND EXPANSION NOTICE. (a)      Tenant may either (i) accept
         the offer set forth in the Second Expansion Notice as set forth above
         or (ii) elect to lease the Second Expansion Space and provide Landlord
         with its determination of Fair Market Rental Value for the Second
         Expansion Space, whereupon the determination of Fair Market Rental
         Value for such space shall be submitted to the process set forth in
         Article 16, by delivering to Landlord a written notice (hereinafter
         called "Tenant's Second Expansion Notice"), provided, in either case,
         Tenant's Second Expansion Notice shall be delivered at least ten (10)
         months prior to the Second Expansion Space Inclusion Date. Each of
         Landlord's and Tenant's notice to the other setting forth their
         respective determinations of Fair Market Rental Value for the Second
         Expansion Space shall constitute each of Landlord's and Tenant's
         "Determination Notice" for purposes of Article 16. The Second Expansion
         Space so accepted by Tenant shall be added to and included in the
         Premises on the Second Expansion Space Inclusion Date. In Tenant's
         Second Expansion Notice, Tenant shall elect one of the following for
         the Second Expansion Space: (i) a five (5) year term; (ii) a five (5)
         year term and a corresponding extension of the expiration date of Lease
         Term to be coterminous with such five (5) year term, or (iii) Tenant
         may exercise its first extension option set forth in Article 15 hereof
         for all the Premises and the Second Expansion Space to provide for
         coterminous lease expirations. If Tenant elects to extend the Lease
         Term pursuant to clauses (ii) or (iii) of the preceding sentence, then
         the Basic Rent and Additional Charges applicable to space then
         comprising the Premises for the Extended Term shall be determined and
         become effective as of the date the initial Lease Term expires, in
         accordance with Article 16 hereof.

         (b)      If Tenant does not give Tenant's Second Expansion Notice (or
         fails to timely give Tenant's Second Expansion Notice) pursuant to the
         provisions of this Article 17, time being of the essence, Landlord
         shall be under no further obligation with respect to the Second
         Expansion Space (the "Second Untaken Space") by reason of this Article
         17, and Tenant shall have waived and relinquished its right under this
         Article 17 to the Second

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<PAGE>

         Untaken Space, and, subject to Article 18, Landlord shall at any and
         all times thereafter be entitled to lease the Second Untaken Space to
         others at such rental and upon such terms and conditions as Landlord in
         its sole discretion may desire, whether such rental terms, provisions
         and conditions are the same as those offered to Tenant or more or less
         favorable.

17.6.    EFFECT OF INCLUSION. Provided that Tenant provides Landlord with
         Tenant's Second Expansion Notice pursuant to Section 17.5, upon the
         Second Expansion Space Inclusion Date, Landlord agrees to lease to
         Tenant and Tenant agrees to lease from Landlord the Second Expansion
         Space for the term designated by Tenant in the Tenant's Second
         Expansion Notice. Upon the occurrence of the Second Expansion Space
         Inclusion Date:

         (a)      the term "Premises" shall be deemed to include the Second
         Expansion Space;

         (b)      the Premises Rentable Area shall be increased by the rentable
         area within the Second Expansion Space, and Tenant's Proportionate
         Share shall be adjusted accordingly;

         (c)      the Basic Rent per annum (on an aggregate but not square
         footage basis) shall be increased by an amount equal to the Fair Market
         Rental Value for the Second Expansion Space, which shall be determined
         in accordance with Article 16 hereof;

         (d)      Additional Charges shall thereafter be computed on the basis
         of the inclusion of the Second Expansion Space into the Premises; and

         (e)      the term of this Lease with respect to the Second Expansion
         Space shall be the term designated in the Tenant's Second Expansion
         Notice.

17.7.    THIRD EXPANSION SPACE. For purposes of this Lease, the "Third Expansion
         Space" shall mean any space in the Building or the 890 Building, and
         shall comprise between 16,000 and 24,000 rentable square feet which is
         not then leased by Tenant. Landlord shall make the Third Expansion
         Space available for occupancy at a date commencing between the tenth
         anniversary of the Commencement Date and the eleventh anniversary of
         the Commencement Date. Such space shall consist of not more than two
         (2) non-contiguous spaces of not less than 5,000 rentable square feet
         each.

         (a)      Provided that, at the time of the giving of "Tenant's Third
         Expansion Notice" and as of the "Third Expansion Space Inclusion Date"
         (as such terms are hereinafter defined), (i) there exists no Default of
         Tenant, (ii) the Lease is still in full force and effect, and (iii)
         Tenant has exercised an Extended Term option pursuant to Article 15,
         Landlord shall offer to Tenant, subject to the provisions of this
         Article 17, the right to add such Third Expansion Space to the Premises
         then demised pursuant to this Lease.

         (b)      The offer made by Landlord to Tenant shall be by a written
         notice (hereinafter called the "Third Expansion Notice"), to be
         provided at least fourteen (14) months prior to the Third Expansion
         Space Inclusion Date and shall specify the space being offered, the
         date such space shall become available for Tenant's occupancy (the
         "Third Expansion Space Inclusion Date"), and Landlord's calculation of
         Fair Market Rental Value. Landlord shall provide Tenant with floor
         plans of the Third Expansion Space (including as-built plans of the
         Third Expansion Space to the extent available) and afford Tenant a
         reasonable opportunity to view the Third Expansion Space within fifteen
         (15) days of the delivery of the Third Expansion Notice.

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<PAGE>

17.8.    TENANTS THIRD EXPANSION NOTICE. (a)      Tenant may either (i) accept
         the offer set forth in the Third Expansion Notice as set forth above or
         (ii) elect to lease the Third Expansion Space and provide Landlord with
         its determination of Fair Market Rental Value for the Third Expansion
         Space, whereupon the determination of Fair Market Rental Value for such
         space shall be submitted to the process set forth in Article 16, by
         delivering to Landlord a written notice (hereinafter called "Tenant's
         Third Expansion Notice"), provided, in either case, Tenant's Third
         Expansion Notice shall be delivered at least twelve (12) months prior
         to the Third Expansion Space Inclusion Date. Each of Landlord's and
         Tenant's notice to the other setting forth their respective
         determinations of Fair Market Rental Value for the Third Expansion
         Space shall constitute each of Landlord's and Tenant's "Determination
         Notice" for purposes of Article 16. The Third Expansion Space so
         accepted by Tenant shall be added to and included in the Premises on
         the Third Expansion Space Inclusion Date.

         (b)      If Tenant does not give Tenant's Third Expansion Notice (or
         fails to timely give Tenant's Third Expansion Notice) pursuant to the
         provisions of this Article 17, time being of the essence, Landlord
         shall be under no further obligation with respect to the Third
         Expansion Space (the "Third Untaken Space") by reason of this Article
         17, and Tenant shall have waived and relinquished its right under this
         Article 17 to the Third Untaken Space, and, subject to Article 18,
         Landlord shall at any and all times thereafter be entitled to lease the
         Third Untaken Space to others at such rental and upon such terms and
         conditions as Landlord in its sole discretion may desire, whether such
         rental terms, provisions and conditions are the same as those offered
         to Tenant or more or lees favorable.

17.9.    EFFECT OF INCLUSION. Provided that Tenant provides Landlord with
         Tenant's Third Expansion Notice pursuant to Section 17.8, upon the
         Third Expansion Space Inclusion Date, Landlord agrees to lease to
         Tenant and Tenant agrees to lease from Landlord the Third Expansion
         Space for the remaining Lease Term. Upon the occurrence of the Third
         Expansion Space Inclusion Date:

         (a)      the term "Premises" shall be deemed to include the Third
         Expansion Space;

         (b)      the Premises Rentable Area shall be increased by the rentable
         area within the Third Expansion Space, and Tenant's Proportionate Share
         shall be adjusted accordingly;

         (c)      the Basic Rent per annum (on an aggregate but not square
         footage basis) shall be increased by an amount equal to the Fair Market
         Rental Value for the Third Expansion Space, which shall be determined
         in accordance with Article 16 hereof;

         (d)      Additional Charges shall thereafter be computed on the basis
         of the inclusion of the Third Expansion Space into the Premises; and

         (e)      the term of this Lease with respect to the Third Expansion
         Space shall be coterminous with the Lease Term.

17.10.   CONDITION OF EXPANSION SPACE. Tenant agrees to accept the First
         Expansion Space, the Second Expansion Space and the Third Expansion
         Space leased hereby "as is" in its condition and state of repair
         existing on the applicable expansion space inclusion date and
         understands that Landlord makes no representations, express or implied,
         as to the condition of the First Expansion Space, the Second Expansion
         Space or the Third Expansion Space, the building equipment and systems
         serving the First Expansion

                                      -59-

<PAGE>

         Space, the Second Expansion Space or the Third Expansion Space or as to
         any other thing or fact related thereto, and that no work, decoration,
         repair, alteration or improvement is to be performed by Landlord to
         prepare the First Expansion Space, the Second Expansion Space or the
         Third Expansion Space for Tenant's occupancy.

17.11.   NO BROKERS. Tenant represents and warrants to Landlord that, with
         respect to the leasing of any First Expansion Space, Second Expansion
         Space of Third Expansion Space, it has not dealt with any brokers or
         finders for which a fee or commission may be payable other than Broker
         and Tenant does hereby agree to defend with counsel acceptable to
         Landlord, indemnify and hold Landlord harmless from and against any
         claim, liability, loss, cost and/or expense, including, without
         limitation, reasonable attorneys' fees and disbursements, arising out
         of any inaccuracy or alleged inaccuracy in the foregoing
         representation.

17.12.   OFFERED LEASE AMENDMENT. In the event Tenant shall lease the First
         Expansion Space, the Second Expansion Space or the Third Expansion
         Space as herein provided, within ten (10) days of Landlord's request
         therefor, Tenant shall execute and deliver an amendment to this Lease
         incorporating the business terms therefor and confirming the terms and
         provisions upon which Tenant is leasing such expansion space
         (hereinafter called an "Offered Lease Amendment"), and the parties
         thereto shall promptly execute and exchange an Offered Lease Amendment,
         and Tenant shall cause Guarantor to execute and deliver a ratification
         of its obligations under the Guaranty. In the event Tenant fails to
         execute a factually accurate Offered Lease Amendment within twenty (20)
         days after Landlord's delivery of same to Tenant or fails to cause
         Guarantor to ratify its obligations as provided above, then, at
         Landlord's sole option, to be exercised by notice given to Tenant, the
         applicable Tenant's expansion notice shall be automatically deemed to
         be terminated and of no further force or effect as if the applicable
         Tenant's expansion notice had not been given, in which event Tenant
         shall be deemed to have waived all rights and Landlord shall be
         released from all obligations under this Article 17.

17.13.   MISCELLANEOUS. (a)        The termination of this Lease shall also
         terminate and render void all of Tenant's options or elections under
         this Article 17 whether or not the same shall have been exercised; and
         nothing contained in this Article shall prevent Landlord from
         exercising any right or action granted to or reserved by Landlord in
         this Lease to terminate this Lease. None of Tenant's options or
         elections set forth in this Article 17 may be severed from this Lease
         or separately sold, assigned or transferred.

         (b)      Except as expressly provided in this Article 17, nothing
         herein shall be deemed to limit Landlord's right to freely discuss and
         negotiate with third parties for the leasing of any space and Tenant's
         sole right will be to make the election to enter into a lease with
         Landlord of the applicable expansion space as described above.

                                   ARTICLE 18

                             RIGHT OF FIRST OFFERING

18.1.    FIRST OFFERING SPACE.

         (a)      Provided that, at the time of the giving of "Tenant's Offering
         Notice" and as of the "First Offering Space Inclusion Date" (as such
         terms are hereinafter defined), there exists no Default of Tenant, and
         the Lease is still in full force and effect, on each January 1 and July
         1 of each calendar year during the Lease Term, beginning July 1,

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         1998, and when otherwise requested by Tenant in writing to Landlord,
         Landlord shall provide Tenant with a written notice of all available
         spaces (or reasonably expected to become available within such six
         month period) in the Building and the 890 Building (the "First Offering
         Space") and the terms and conditions on which Landlord is then
         marketing such space to prospective third party tenants and shall offer
         to Tenant, subject to the provisions of this Article 18, the right to
         add such First Offering Space to the Premises then demised pursuant to
         this Lease.

         (b)      The offer made by Landlord to Tenant shall be by a written
         notice (hereinafter called the "First Offer Notice") which offer shall
         specify the space being offered, the date such space shall become
         available for Tenant's occupancy (the "First Offering Space Inclusion
         Date"), and Landlord's calculation of Fair Market Rental Value.
         Landlord shall provide Tenant with floor plans of the First Offering
         Space (including as-built plans of the First Offering Space to the
         extent available) and afford Tenant a reasonable opportunity to view
         the First Offering Space within five (5) Business Days of the delivery
         of the First Offer Notice to the extent such space is constructed. The
         First Offering Space shall be offered for a term that is conterminous
         with the Lease Term, but Landlord shall not be obligated to offer such
         First Offering Space for a term less than five (5) years.

18.2.    TENANT'S OFFERING NOTICE (a)       Tenant may either (i) accept the
         offer set forth in the First Offer Notice as set forth above or (ii)
         elect to lease all or a portion of the First Offering Space and provide
         Landlord with its determination of Fair Market Rental Value for the
         First Offering Space, whereupon the determination of Fair Market Rental
         Value shall be submitted to the process set forth in Article 16 hereof,
         by delivering to Landlord a written notice (hereinafter called
         "Tenant's Offering Notice") specifying which portion of the First
         Offering Space Tenant desires to lease, provided Tenant's Offering
         Notice shall be delivered within ten (10) Business Days after delivery
         by Landlord of the First Offer Notice to Tenant. Any First Offering
         Space so accepted by Tenant shall be added to and included in the
         Premises on the First Offering Space Inclusion Date. Each of Landlord's
         and Tenant's notice to the other setting forth their respective
         determination of Fair Market Rental Value for the First Offering Space
         shall constitute each of Landlord's and Tenant's "Determination Notice"
         for purposes of Article 16.

         (b)      If Tenant does not give Tenant's Offering Notice (or fails to
         timely give Tenant's Offering Notice) pursuant to the provisions of
         this Article 18, time being of the essence. Landlord shall be under no
         further obligation with respect to the First Offering Space (the
         "Untaken Space") by reason of this Article 18, and Tenant shall have
         waived and relinquished its right under this Article 18 to the Untaken
         Space until receipt by Tenant of any subsequent First Offer Notice, and
         Landlord shall at any and all times thereafter, until receipt by Tenant
         of any subsequent First Offer Notice, be entitled to lease the Untaken
         Space to others at such rental and upon such terms and conditions as
         Landlord in its sole discretion may desire, whether such rental terms,
         provisions and conditions are the same as those offered to Tenant or
         more or less favorable.

18.3.    EFFECT OF INCLUSION. Provided that Tenant provides Landlord with
         Tenant's Offering Notice pursuant to Section 18.2, upon the First
         Offering Space Inclusion Date, Landlord agrees to lease to Tenant and
         Tenant agrees to lease from Landlord the First Offering Space for the
         term offered in the First Offer Notice. Upon the occurrence of the
         First Offering Space Inclusion Date:

         (a)      the term "Premises" shall be deemed to include the First
         Offering Space;

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<PAGE>

         (b)      the Premises Rentable Area shall be increased by the rentable
         area within the First Offering Space, and Tenant's Proportionate Share
         shall be adjusted accordingly;

         (c)      the Basic Rent per annum (on an aggregate but not square
         footage basis) shall be increased by an amount equal to the Fair Market
         Rental Value for the First Offering Space, which shall be determined in
         accordance with Article 16 hereof;

         (d)      Additional Charges shall thereafter be computed on the basis
         of the inclusion of the First Offering Space into the Premises; and

         (e)      the term of this Lease with respect to the First Offering
         Space (and, if applicable, the Premises) shall be the term offered in
         the First Offer Notice.

18.4.    CONDITION OF FIRST OFFERING SPACE. Tenant agrees to accept any First
         Offering Space leased hereby "as is" in its condition and state of
         repair existing on the First Offering Space Inclusion Date and
         understands that Landlord makes no representations, express or implied,
         as to the condition of the First Offering Space, the building equipment
         and systems serving the First Offering Space or as to any other thing
         or fact related thereto, and that no work, decoration, repair,
         alteration or improvement is to be performed by Landlord to prepare the
         First Offering Space for Tenant's occupancy.

18.5.    NO BROKERS. Tenant represents and warrants to Landlord that, with
         respect to the leasing of any First Offering Space, it has not dealt
         with any brokers or finders for which a fee or commission may be
         payable other than Broker and Tenant does hereby indemnify Landlord and
         agrees to hold it harmless from and against any liability, loss, cost
         and/or expense, including, without limitation, reasonable attorneys'
         fees and disbursements, arising out of any inaccuracy or alleged
         inaccuracy in the foregoing representation.

18.6.    RIGHT OF FIRST OFFERING LEASE AMENDMENT. In the event Tenant shall
         lease the First Offering Space as herein provided, within ten (10) days
         of Landlord's request therefor, Tenant shall execute and deliver an
         amendment to this Lease incorporating the business terms therefor and
         confirming the terms and provisions upon which Tenant is leasing the
         First Offering Space (hereinafter called the "Right of Offering Lease
         Amendment"), and the parties thereto shall promptly execute and
         exchange the Right of Offering Lease Amendment, and Tenant shall cause
         Guarantor to execute and deliver a ratification of its obligations
         under the Guaranty. In the event Tenant fails to execute a factually
         accurate Right of Offering Lease Amendment within twenty (20) days
         after Landlord's delivery of same to Tenant or fails to cause Guarantor
         to ratify its obligations as provided above, then, at Landlord's sole
         option, to be exercised by notice given to Tenant, Tenant's Offering
         Notice shall be automatically deemed to be terminated and of no further
         force or effect as if Tenant's Offering Notice had not been given, in
         which event Tenant shall be deemed to have waived all rights and
         Landlord shall be released from all obligations under this Article 18.

18.7.    MISCELLANEOUS. (a) The termination of this Lease shall also terminate
         and render void all of Tenant's options or elections under this Article
         18 whether or not the same shall have been exercised; and nothing
         contained in this Article shall prevent Landlord from exercising any
         right or action granted to or reserved by Landlord in this Lease to
         terminate this Lease. None of Tenant's options or elections set forth
         in this Article 17 may be severed from this Lease or separately sold,
         assigned or transferred.

                                      -62-

<PAGE>

         (b)      Except as expressly provided in this Article 18, nothing
         herein shall be deemed to limit Landlord's right to freely discuss and
         negotiate with third parties for the leasing of any space and Tenant's
         sole right will be to make the election to enter into a lease with
         Landlord of the First Offering Space as described above.

                                   ARTICLE 19

                                     SIGNAGE

         (a)      At Tenant's sole expense, Tenant shall have the right to
install interior signs and suite number designations on the entrance doors to
the Premises and on the walls in the elevator lobbies on each full or partial
floor of the Premises leased to Tenant, provided, however that the quality,
type, content, color, material, manner of installation, size and design of any
and all such signs must be approved by Landlord prior to the installation
thereof, which approval shall not be unreasonably withheld.

         (b)      In the event that the Massachusetts Medical Society exercises
its right to place its name on a sign at the Winter Street entrance to the
Complex, then Landlord shall provide Tenant with the right to place Tenant's
corporate logo at such entrance sign, provided, however, that (a) the quality,
type, content, color, material, manner of installation, size and design of such
signage shall be in conformity with building standards adopted by Landlord in
its reasonable discretion, and (b) such logo shall be installed by Landlord or
its contractor at Tenant's sole expense.

         (c)      Landlord, at its sole expense, shall provide building standard
signage (a) for the Complex as a whole along the entrance road from Winter
Street to the Complex directing tenants, employees, guests and vendors to the
Complex and (b) at the entrance to the Complex directing tenants, employees,
guests and vendors to the various buildings within the Complex, provided that
such signage shall be of a quality, type, content, color, material, manner of
installation, size and design in conformity with building standards adopted by
Landlord in its reasonable discretion.

         (d)      At Landlord's sole expense, Landlord shall install an
exclusive, free-standing monument in the entrance area located in the front of
the Building on which Tenant shall have the right to install, at Tenant's sole
expense, Tenant's corporate logo, provided that such logo shall be of a quality,
type, content, color, material, manner of installation, size and design in
conformity with building standards adopted by Landlord in its reasonable
discretion. Such monument shall be located as shown on Exhibit N hereto.

         (e)      Landlord reserves the right to provide other tenants of the
Building that lease in excess of 40,000 rentable square feet of space with a
separate, free-standing sign monument of a quality, type, content, color,
material, manner of installation, size and design in conformity with building
standards adopted by Landlord in its reasonable discretion (but of less
prominence than the monument described in (d) above). Such monument shall be
located as shown on Exhibit N hereto.

         (f)      The Tenant named hereunder shall be entitled to provide one of
its permitted subtenants which leases in excess of 40,000 rentable square feet
of Premises Rentable Area the right to place such subtenant's corporate logo on
the monument described in (e) above, at Tenant's expense, provided that such
subtenant's logo shall be of a quality, type, content, color, material, manner
of installation, size and design in conformity with building standards adopted
by Landlord in its reasonable discretion.

                                      -63-

<PAGE>

         (g)      Tenant will not place on the exterior of the Premises
(including both interior and exterior surfaces of doors and interior surfaces of
windows) or on any part of the Building outside the Premises, any signs, symbol,
advertisement or the like visible to public view outside of the Premises.
Landlord will not withhold consent for signs, corporate logos or lettering on
the entry doors to the Premises provided such signs conform to building
standards adopted by Landlord in its reasonable discretion and Tenant has
submitted to Landlord a plan or sketch in reasonable detail (showing, without
limitation, size, color, location, materials and method of affixation) of the
sign to be placed on such entry doors. Landlord agrees, however, to maintain, at
Tenant's expense and in accordance with building standards adopted by Landlord
in its sole discretion, a tenant directory in the lobby of the Building (and, in
the case of multi-tenant floors, in that floor's elevator lobby) in which will
be placed Tenant's name, Tenant's subtenants' name(s) and the location of the
Premises in the Building.

         (h)      All signs and monuments permitted pursuant to this Article 19
shall comply with (a) all applicable laws, rules, regulations, requirements, and
orders of all governmental authorities, agencies and departments (collectively,
"Applicable Requirements"), including without limitation the requirement of
obtaining all necessary permits, approvals or consents and (b) all restrictions,
covenants and agreements relating thereto of record. To the extent Tenant is
responsible for the installation of any signage, such installation shall be made
and performed in accordance with Section 5.2.

                                   ARTICLE 20

                              ADDITIONAL EQUIPMENT

20.1     At Tenant's sole expense, Tenant shall have the right during the Lease
Term, to mount, install and maintain a satellite dish or dishes, whip
antenna(e), an emergency generator and/or a UPS system on the roof of the
Building and, to the extent the Tenant then leases space at the 890 Building, on
the roof of the 890 Building, and to install and maintain reasonable cabling for
such equipment to the Premises, provided, however, that (a) the quality, type,
costs, material, design, size or location of any and all such equipment and all
screening or fencing thereof shall be approved by Landlord prior to the
installation thereof, which approval shall not be unreasonably withheld; (b)
such equipment and screening and fencing thereof, shall comply with all
Applicable Requirements, including without limitation the requirement of
obtaining all necessary permits, approvals or consents; (c) such installation
shall be made and performed in accordance with Section 5.2; and (d) such
equipment and the screening or fencing thereof shall comply with all
restrictions, covenants and agreements relating thereto of record and shall be
designed to preserve the overall aesthetic appearance of the Complex.

                                   ARTICLE 21

                                   ARBITRATION

         In the event of a dispute between the parties hereto, such dispute may
be determined by arbitration as provided herein if either party elects to do so,
provided, however, that disputes regarding the determination of Fair Market
Rental Value shall be subject to arbitration in accordance with the provisions
of Article 16. Such arbitration shall take place in Boston, Massachusetts by a
board of three (3) arbitrators, in accordance with the Commercial Arbitration
Rules then in effect of the American Arbitration Association (or, if such
association shall not then be in existence, such other organization, if any, as
shall then have become the successor of said association and if there shall be
no successor of said association, then in accordance with the then prevailing
provisions of the laws of the Commonwealth of

                                      -64-

<PAGE>

Massachusetts relative to arbitration). As soon as possible, but in any event
within the next ten (10) days after the first two arbitrators are selected, the
two arbitrators so selected shall select a third arbitrator. Each arbitrator
shall be a broker, appraiser or consultant with at least ten (10) years'
continuous experience with respect to commercial office building leasing issues
in the greater Boston area involving properties similar to the Building and
cannot be affiliated with either Landlord or Tenant. If any party fails to
timely so nominate an arbitrator, the other may request the director of the
regional office of the American Arbitration Association (or the successor
organization, or if no such successor organization exists, then to an
organization composed of persons of similar professional qualifications) which
encompasses the greater Boston area (the "Director") to do so instead of the
failing party. In the event two (2) arbitrators fail to appoint or agree upon a
third arbitrator within such ten (10) day period, a third arbitrator shall be
selected by Landlord and Tenant if they so agree upon such third arbitrator
within a further period of ten (10) days. If Landlord and Tenant cannot agree
upon the third arbitrator, Landlord or Tenant shall request the Director to do
so. In the event of the failure, refusal or inability of any arbitrator to act,
a new arbitrator shall be appointed in his stead, which appointment shall be
made in the same manner as hereinbefore provided. At the request of either
party, the arbitrators shall authorize the service of subpoenas for the
production of documents or attendance of witnesses.

Within twenty (20) days after their appointment, the arbitrators so chosen shall
hold a hearing at which each party may submit evidence, be heard and cross
examine witnesses, with each party having at least ten (10) days advance notice
of the hearing. The hearing shall be conducted such that each of Landlord and
Tenant shall have reasonably adequate time to present oral evidence or argument,
but either party may present whatever written evidence it deems appropriate
prior to the hearing (with copies of any such written evidence being sent to the
other party).

The decision of the arbitrators so chosen shall be given within a period of ten
(10) days after the conclusion of such hearing. The decision in which any two
(2) Arbitrators so appointed and acting hereunder concur shall in all cases be
binding and conclusive upon the parties and shall be the basis for a judgment
entered in any court of competent jurisdiction. Landlord and Tenant may at any
time by mutual written agreement discontinue arbitration proceedings and
themselves agree upon any such matter submitted to arbitration.

If the decision of the Arbitrators under this Article shall be held by a court
of competent jurisdiction to be unenforceable for any reason (Landlord and
Tenant hereby affirmatively stating it is their intent and agreement that the
decision of the arbitrators will be legally enforceable as to them), then the
matter submitted to arbitration shall be subject to litigation.

Each party shall pay its own counsel fees, fees of its appointed arbitrator and
expenses, if any, in connection with any arbitration under this Article, and
the parties shall share equally all other expenses and fees of any such
arbitration. The determination rendered in accordance with the provisions of
this Article shall be final and binding in resolving such dispute. The
arbitrators shall not have the power to add to, modify, or change any of the
provisions of this Lease. Pending the resolution of such disputed matter, Tenant
shall pay to Landlord any amounts claimed by Landlord, provided that in the
event that the final determination of the arbitrator is in Tenant's favor,
Landlord shall refund to Tenant, the amount of such overpayment plus interest
thereon from the date paid until reimbursed at the rate equal to two percent
(2%) over the base rate in effect from time to time at Fleet National Bank.

                                      -65-

<PAGE>

IN WITNESS WHEREOF, Landlord and Tenant have caused this Lease to be duly
executed, under seal, by persons hereunto duly authorized, in multiple copies,
each to be considered an original hereof, as of the date first set forth above.

LANDLORD:         880 WINTER STREET, L.L.C.

                  By: Winter Street OpCo, L.L.C., its managing member

                      By: Leggat McCall Opportunity
                          Investors, LLC, its managing member

                          By: LM Opportunity
                              Management LLC, its managing member

                              By: /s/ Eric B. Sheffels
                                 -------------------------------------
                              Name: Eric B. Sheffels
                              Title: Vice President

TENANT:           BGS SYSTEMS, INC.

Attest:           By: /s/ William M. Austin
                      ------------------------------------
                          William M. Austin
                          SVP & CFO

By: /s/ Mark D. Taylor
    ------------------------------
Name: Mark D. Taylor
      Vice President

                                      -66-

<PAGE>

                                    EXHIBIT A

                             FLOOR PLANS OF PREMISES

<PAGE>

                                    EXHIBIT A

                           [MAP OF FIRST FLOOR PLAN]

<PAGE>

                           [MAP OF SECOND FLOOR PLAN]

<PAGE>

                           [MAP OF THIRD FLOOR PLAN]

<PAGE>

                                    EXHIBIT B

                                    SITE PLAN

<PAGE>

                               [MAP OF SITE PLAN]

<PAGE>

                                    EXHIBIT C

                           COMMENCEMENT DATE AGREEMENT

THIS COMMENCEMENT DATE AGREEMENT made this _______________ day of
__________________, 19__, between 880 Winter Street, L.L.C., a Delaware limited
liability company ("Landlord"), having an office c/o Leggat McCall Properties,
L.P., 10 Post Office Square, Boston, Massachusetts 02109, and BGS Systems, Inc.,
a ____________________ corporation ("Tenant") having an office at One First
Avenue, Waltham, MA 02154.

                               W I T N E S S E T H:

         1.       Landlord and Tenant heretofore have entered into a written
Lease dated May _____, 1998 (hereinafter referred to as the "Lease") for the
leasing by Landlord to Tenant of certain space on the first, second and third
floors in the building known as 880 Winter Street, Waltham, Massachusetts, all
as in the Lease more particularly described.

         2.       Pursuant to Article 3 of the Lease, Landlord and Tenant agree
that the Commencement Date of the Lease Term of the Lease occurred
on ________________________, _____; and that the Lease Term shall expire, unless
sooner terminated, on ____________________, _____.

         IN WITNESS WHEREOF, Landlord and Tenant have respectively signed and
sealed this Commencement Date Agreement as the date hereinabove set forth.

         LANDLORD:       880 WINTER STREET, L.L.C.

                         By: Winter Street OpCo, L.L.C., its managing member

                             By: Leggat McCall Opportunity
                                 Investors, LLC, its managing member

                                  By: LM Opportunity
                                      Management LLC, its managing member

                                      By: ______________________________
                                      Name: Eric B. Sheffels
                                      Title: Vice President

         TENANT:         BGS SYSTEMS, INC.

                         By: ______________________
                         Name: ____________________
                         Title: ___________________

<PAGE>

                                    EXHIBIT D

                            880 Winter Street, L.L.C.
                        c/o Leggat McCall Properties, L.P.
                              10 Post Office Square
                                Boston, MA 02109

                         _________________________, 1998

[Name of Contact]
BGS Systems, Inc.
One First Avenue
Waltham, MA 02154

         Re:      BGS Systems, Inc.
                  [Premises Rentable Area on the First, Second and Third Floors]
                  880 Winter Street, Waltham, MA

Dear [Name of Contact]:

         Reference is made to that certain Lease, dated as of_______________,
1998, between 880 Winter Street, L.L.C. as Landlord, and BGS Systems, Inc. as
Tenant, with respect to 880 Winter Street, Waltham, Massachusetts. In accordance
with Section 3.2(a) of the Lease, this is to confirm that the "Plans" referred
to in such Section 3.2(a) are those plans and specifications prepared by
____________, and described as follows:

         DATE                   TITLE                   #PAGES

         If the foregoing is in accordance with your understanding, would you
kindly execute this letter in the space provided below, and return the same to
us for execution by Landlord, whereupon it will become a binding agreement
between us.

                            Very truly yours,

                            880 WINTER STREET, L.L.C.

                            By: Winter Street OpCo, L.L.C., its managing member

                                By: Leggat McCall Opportunity
                                    Investors, LLC, its managing member

                                    By: LM Opportunity
                                        Management LLC, its managing member

                                        By: __________________________
                                        Name: Eric B. Sheffels
                                        Title: Vice President

<PAGE>

Accepted and Agreed:

BGS SYSTEMS, INC.

By:_____________________
Name:___________________
Title:__________________

                                      -2-

<PAGE>

                                    EXHIBIT E
                               OPERATING EXPENSES

Without limitation, and subject to the percentage allocation set forth in
Section 9.1, Operating Expenses shall include:

         1.       All expenses incurred by Landlord, Landlord's agents or
Landlord's affiliates which shall be directly related to employment of
personnel, including amounts incurred for wages, salaries and other compensation
for services, payroll, social security, unemployment and similar taxes,
workmen's compensation insurance, disability benefits, pensions,
hospitalization, retirement plans and group insurance, uniforms and working
clothes and the cleaning thereof, and expenses imposed on Landlord, Landlord's
agents, or Landlord's affiliates pursuant to any collective bargaining agreement
for the services of employees of Landlord or Landlord's agents in connection
with the operation, repair, maintenance, cleaning, management and protection of
the Property and the Site, and its mechanical systems including, without
limitation, day and night supervisors, property manager, accountants,
bookkeepers, janitors, carpenters, engineers, mechanics, electricians and
plumbers and personnel engaged in supervision of any of the persons mentioned
above; provided that, if any such employee is also employed on other property of
Landlord or Landlord's affiliates, such compensation shall be suitably prorated
among the Property and such other properties.

         2.       The cost of services, utilities (other than the electricity
furnished to the Premises pursuant to Section 7.5), materials and supplies
(including taxes thereon) furnished or used in the operation, repair,
maintenance, cleaning, management and protection of the Property and the Site,
including without limitation fees, if any, imposed upon Landlord or Landlord's
affiliates, or charged to the Property and/or the Site, by the state or
municipality in which the Property is located on account of the need for
increased or augmented public safety services and including, without limitation,
the provision of the following services: cleaning and janitorial services to the
Premises on Business Days, exterior window cleaning, water, elevator service,
exterior maintenance, security, heating, ventilation and air-conditioning and
utilities, including Base Building electricity.

         3.       The cost of replacements for tools and other similar equipment
used in the repair, maintenance, cleaning and protection of the Property or the
Site, provided that, in the case of any such equipment used jointly on other
property of Landlord or Landlord's affiliates, such costs shall be suitably
prorated among the Property and such other properties.

         4.       Where the Property is managed by Landlord or an affiliate of
Landlord, a sum equal to the amounts customarily charged by management firms in
the Suburban Route 128/Waltham area for similar properties, but in no event more
than five percent (5%) of gross annual income (or less than two and one-quarter
percent (2.25%) of gross annual income, for purposes of the calculation of Base
Operating Expenses only), whether or not actually paid, or where managed by
other than Landlord or an affiliate thereof, the amounts accrued for management
but in no event more than five percent (5%) of gross annual income (or less than
two and one-quarter percent (2.25%) of gross annual income, for purposes of the
calculation of Base Operating Expenses only) (such management fees to be
incurred on a building by building basis), together with, in either case,
amounts accrued for legal and other professional fees relating to the Property
and the Site, but excluding such fees and commissions paid in connection with
services rendered for securing, preparing or renewing leases or litigating
disputes and for matters not related to the normal administration and operation
of the Building.

<PAGE>

         5.       Premiums for insurance against damage or loss to the Building
from such hazards as shall from time to time be generally required by
institutional mortgagees in the Suburban Route 128/Wellesley-Waltham area for
similar properties, including, but not by way of limitation, insurance covering
loss of rent attributable to any such hazards, and general liability insurance
but excluding any increases in premiums resulting from payments by the insurer
of claims arising from any act or neglect of Tenant, its assignee, subtenant,
contractor or invitees payable by Tenant pursuant to Section 7.2.

         6.       If, during the Lease Term, Landlord or Landlord's affiliates
shall make a capital expenditure either (1) for the reasonably intended purpose
of reducing Operating Expenses undertaken in good faith by Landlord based upon
engineering or other information available to Landlord, upon which Landlord
could reasonably conclude that the cost of such capital improvement(s)
thereafter will, within a reasonable time, result in a reduction of Operating
Expenses equal to or greater than the cost of such capital improvements, whether
or not such a reduction does in fact occur, or (2) pursuant to a requirement of
law, ordinance, order, rule or regulation of any public authority having
jurisdiction or a mandatory (i.e., the failure to comply with any such
requirement will result in the refusal of reputable insurers to issue any policy
which Landlord is obligated to carry pursuant to this Lease or at other than
commercially reasonable rates) requirement of any insurance carrier or insurance
rating organization board, the total cost of which is not properly includable in
Operating Expenses for the Operating Year in which it was made, there shall
nevertheless be included in such Operating Expenses for the Operating Year in
which it was made and in Operating Expenses for each succeeding Operating Year
the annual charge-off of such capital expenditure. Annual charge-off shall be
determined by dividing the original capital expenditure plus an interest factor,
reasonably determined by Landlord, as being the interest rate then being charged
for long-term mortgages by institutional lenders on like properties within the
locality in which the Building is located, by the number of years of useful life
of the capital expenditure; and the useful life shall be determined reasonably
by Landlord in accordance with generally accepted accounting principles and
practices in effect at the time of making such expenditure.

         7.       Costs for electricity, water and sewer use charges, and other
utilities supplied to the Property and not paid for directly (i.e., other than
by escalation payments) by tenants.

         8.       Betterment assessments provided the same are apportioned
equally over the longest period permitted by law.

         9.       Amounts paid to independent contractors for services,
materials and supplies furnished for the operation, repair, maintenance,
cleaning and protection of the Property and the Site.

         The following costs and expenses shall be excluded from Operating
Expenses:

         1.       Costs incurred in connection with the construction of the
original Building improvements, except to the extent such costs are capital
expenditures which will be amortized pursuant to Paragraph 6 above.

         2.       The cost of defects in the construction, design or equipping
of the Building which are wholly covered by a warranty or guaranty then in
effect from the contractor or supplier responsible for such defect.

         3.       Costs incurred in connection with the making of repairs which
are the obligation of another tenant in the Building.

                                       -2-

<PAGE>

         4.       Interest, fines or penalties for any late payments by Landlord
not due to the act or neglect of Tenant or its agent.

         5.       Legal fees incurred in connection with Landlord's
noncompliance or violation of law.

         6.       Costs of repairs, replacements or other work occasioned by
fire, windstorm or other casualty, or the exercise by governmental authorities
of the right of eminent domain.

         7.       Leasing commissions, attorney's fees, costs, disbursements and
other expenses incurred by Landlord or its agents in connection with
negotiations for leases with tenants, other occupants or prospective tenants or
other occupants of the Building, and similar costs incurred in connection with
disputes with and/or enforcement of any leases with tenants, other occupants, or
prospective tenants or other occupants of the Building.

         8.       "Tenant allowances", "tenant concessions", workletters, and
other costs or expenses (including permit, license and inspection fees) incurred
in completing, fixturing, furnishing, renovating or otherwise improving,
decorating or redecorating space for tenants or other occupants of the Building,
or vacant, leaseable space in the Building, including space planning/interior
architecture fees for same.

         9.       Costs of correcting defects, including any allowances for
same, in construction of the Building (including latent defects) or equipment
used therein (or the replacement of defective equipment), any associated parking
facilities, or other improvements, or in the equipment used therein of which
Landlord has been given notice by any tenant within two years of the
Commencement Date.

         10.      Depreciation, other "non-cash" expense items or amortization,
except for amortization charges as provided for in inclusion item 6 above.

         11.      Costs of a capital nature, except as provided for in inclusion
item 6 above, including, but not limited to, capital additions, capital
improvements, capital repairs, capital maintenance, capital alterations, capital
replacements, capital equipment and capital tools, and/or capital redesign, all
in accordance with generally accepted accounting principles, consistently
applied.

         12.      Costs in connection with services (including electricity),
items or other benefits of a type which are not standard for the Building and
which are not available to Tenant without specific charge therefor, but which
are provided to another tenant or occupant of the Building, whether or not such
other tenant or occupant is specifically charged therefor by Landlord.

         13.      Services, items and benefits for which Tenant or any other
tenant or occupant of the Building specifically reimburses Landlord or for which
Tenant or any other tenant or occupant of the Building pays third persons.

         14.      Costs or expenses (including fines, penalties and legal fees)
incurred due to the violation by Landlord, its employees, agents and/or
contractors, any tenant (other than Tenant) or other occupant of the Building,
of any terms and conditions (other than by Tenant) of this Lease or of the
leases of other tenants in the Building, and/or any valid, applicable laws,
rules, regulations and codes of any federal, state, county, municipal or other
governmental authority having jurisdiction over the Property that would not have
been incurred but for such violation by Landlord, its employees, agents, and/or
contractors, it being intended that each party shall

                                       -3-

<PAGE>

be responsible for the costs resulting from its own violation of such leases and
laws, rules, regulations and codes as same shall pertain to the Property.

         15.      Penalties for late payment by Landlord, including, without
limitation, taxes, equipment leases, etc.

         16.      Costs directly resulting from the gross negligence or willful
misconduct of Landlord, its employees, agents and/or contractors.

         17.      Payments in respect of overhead and/or profit to any
subsidiary or Affiliate (hereinafter defined) of Landlord as a result of a
non-competitive selection process for services (other than the management fee)
on or to the Property, or for goods, supplies or other materials, to the extent
that the costs of such services, goods, supplies and/or materials exceed the
costs that would have been paid had the services, goods, supplies or materials
been provided by parties unaffiliated with Landlord of similar skill, competence
and experience, on a competitive basis.

         18.      Payments of principal, finance charges or interest on debt or
amortization on any mortgage, deed of trust or other debt, and rental payments
(or increases in same) under any ground or underlying lease or leases (except to
the extent the same may be made to pay or reimburse, or may be measured by, real
estate taxes).

         19.      Taxes payable by Landlord other than Taxes.

         20.      Real estate taxes allocable to the leasehold improvements of
other tenants or occupants of the Building.

         21.      Except for the management fee, costs of Landlord's general
overhead and general administrative expenses (individual, partnership or
corporate, as the case may be), which costs would not be chargeable as an
operating expense in accordance with generally accepted accounting principles,
consistently applied.

         22.      Rentals and other related expenses, if any, incurred in
leasing air conditioning systems, elevators or other equipment ordinarily
considered to be of a capital nature, except equipment which is used in
providing janitorial services and which is not affixed to the Building.

         23.      Costs incurred in installing, operating, maintaining and
owning any specialty items or services not normally installed, operated and
maintained in buildings comparable to the Building and not necessary for
Landlord's operation, repair and maintenance of, and the providing of required
services for, the Building and/or any associated parking facilities, including,
but not limited to, an observatory, beacon(s), broadcasting facilities (other
than the Building's music system, and life support and security systems),
helicopter pad, promotions, and displays, but specifically excluding costs
incurred in installing, operating, maintaining and owning the cafeteria, the
fitness center and related shower and locker facilities, the shared use
conference center, the concierge, the kiosk and any other amenities normally
found in comparable office buildings in the Waltham area.

         24.      Advertising and promotional expenses incurred in connection
with leasing of rentable areas in the Building.

         25.      Costs or expenses for sculpture, paintings or other works of
art, including costs incurred with respect to the purchase, ownership, showing,
promotion, and/or securing of same.

                                       -4-

<PAGE>

         26.      Costs for which Landlord is compensated or reimbursed by
insurance or other means of recovery to the extent the proceeds are compensation
for expenses which previously were included in Operating Expenses for the years
in which such proceeds were received.

         27.      Costs of correcting or repairing defects in the Building
and/or any associated parking facilities, and/or equipment or the replacement of
defective equipment to the extent that such costs are reimbursed under
warranties of manufacturers, suppliers or contractors, or are otherwise borne by
parties other than Landlord.

         28.      Costs of restoration or repair of the Building as a result of
total or partial destruction or condemnation thereof.

         29.      Contributions to operating expense reserves.

         30.      Contributions to charitable organizations.

         31.      Costs incurred in removing the property of former tenants
and/or other occupants of the Building.

         32.      Rental and any other expenses, including wages, salaries and
benefits, and adjustments thereto, for Landlord's leasing offices.

         33.      Consulting costs and expenses incurred by Landlord except to
the extent same relate exclusively to the improved management or operation of
the Building.

         34.      The costs of any "tap fees" or one-time lump sum sewer or
water connection fees for the Building.

         35.      Costs or fees relating to the defense of Landlord's title to
or interest in the Property, or any part thereof.

         36.      Any other expense which, under generally accepted accounting
principles, consistently applied, would not be considered to be a normal
maintenance or operating expense of the Building.

The term "Affiliate" shall mean and refer to any person or entity controlling,
controlled by, or under common control with another such person or entity.
"Control", as used herein, shall mean the possession, direct or indirect, of the
power to direct or cause the direction of the management and policies of such
controlled person or entity; the ownership, directly or indirectly, of at least
fifty-one percent (51%) of the voting securities of, or possession of the right
to vote, in the ordinary direction of its affairs, at least fifty-one percent
(51%) of the voting interest in, any person or entity shall be presumed to
constitute such control. In the case of Landlord, the term Affiliate shall
include any person or entity controlling or controlled by or under common
control with any managing member of Landlord or any managing member of
Landlord's managing member.

                                       -5-

<PAGE>

                                    EXHIBIT F

                              RULES AND REGULATIONS

I.       The following regulations are generally applicable:

         1.       The public sidewalks, entrances, passages, courts, elevators,
vestibules, stairways, corridors or halls shall not be obstructed or encumbered
by Tenant (except as necessary for deliveries) or used for any purpose other
than ingress and egress to and from the Premises.

         2.       No awnings, curtains, blinds shades, screens or other
projections shall be attached to or hung in, or used in connection with, any
window of the Premises or any outside wall of the Building. Such awnings,
curtains, blinds, shades, screens or other projections must be of a quality,
type, design and color, and attached in the manner, approved by Landlord.

         3.       No show cases or other articles shall be put in front of or
affixed to any part of the exterior of the Building, nor places in the halls,
corridors or vestibules.

         4.       The water and wash closets and other plumbing fixtures shall
not be used for any purposes other than those for which they were designed and
constructed, and no sweepings, rubbish, rags, acids or like substances shall be
deposited therein. All damages resulting from any misuse of the fixtures shall
be borne by the Tenant.

         5.       Tenant shall not use the Premises or any part thereof, or
permit the Premises or any part thereof to be used, for manufacturing. Tenant
shall not use the Premises or any part thereof or permit the Premises or any
part thereof to be used as a public employment bureau or for the sale of
property of any kind at auction, except in connection with Tenant's business.

         6.       Tenant must, upon the termination of its tenancy, restore to
the Landlord all locks, cylinders and keys to offices and toilet rooms of the
Premises.

         7.       The Landlord reserves the right to exclude from the Building
between the hours of 6 p.m. and 8 a.m. and at all hours on Sunday and holidays
all persons connected with or calling upon the Tenant who do not present a pass
to the Building signed by the Tenant. Tenant shall be responsible for all
persons for whom it issues any such pass and shall be liable to the Landlord for
all wrongful acts of such persons.

         8.       The requirements of Tenant will be attended to only upon
application at the Building Superintendent's Office. Employees of Landlord shall
not perform any work or do anything outside of their regular duties, unless
under special instructions from the office of the Landlord.

         9.       There shall not be used in any space, or in the public halls
of the Building, either by Tenant or by jobbers or others, in the delivery or
receipt of merchandise, any hand trucks, except those equipped with rubber tires
and side guards.

         10.      No bicycles, vehicles or animals of any kind shall be brought
into or kept in or about the Premises.

         11.      No tenant shall make, or permit to be made, any unseemly or
disturbing noises or disturb or interfere with occupants of this or neighboring
building or premises or those having business with them whether by use of any
musical instrument, radio, talking machine,

<PAGE>

unmusical noise, whistling, singing, or in any other way. No tenant shall throw
anything out of the doors, windows or skylights or down the passageways.

         12.      The Premises shall not be used for lodging or sleeping or for
any immoral or illegal purpose.

         13.      No smoking shall be permitted in the Premises or the Building.
Smoking shall only be permitted in smoking areas outside of the Building which
have been designated by the Landlord.

         14.      Tenants shall cooperate with Landlord in obtaining maximum
effectiveness of the cooling system by closing draperies when sun's rays fall
directly on windows of Premises.

         15.      Any person desiring to use the health and fitness facility
shall first execute and deliver to the Landlord a liability waiver form prepared
by the Landlord.

II.      The following regulations are applicable to any Alterations or any
other work being undertaken by or for Tenant by Tenant's contractors in the
Premises:

A.       General

         1.       All Alterations to be made by Tenant in, to or about the
Premises shall be made in accordance with the requirements of this Exhibit and
by contractors or mechanics reasonably approved by Landlord.

         2.       Tenant shall, prior to the commencement of any work, submit
for Landlord's written approval, complete plans for the Alterations. Drawings
are to be complete with full details and specifications for all of the
Alterations.

         3.       Alterations must comply with the Building Code applicable to
the Property and  the requirements, rules and regulations and any other
governmental agencies having jurisdiction.

         4.       No work shall be permitted to commence without the Landlord
being furnished with a valid permit and all other necessary approvals from
agencies having jurisdiction.

         5.       All demolition, removals or other categories of work that may
inconvenience other tenants or disturb Building operations, must be scheduled
and performed before or after normal Business Hours and Tenant shall provide the
Building manager with at least 24 hours' notice prior to proceeding with such
work.

         6.       All inquiries, submissions, approvals and all other matters
shall be processed through the Building manager.

                                       -2-
<PAGE>

B.       Prior to Commencement of Work

         1.       Tenant shall submit to the Building manager a request, not to
be unreasonably withheld, to perform the work. The request shall include the
following enclosures:

         (i)      A list of Tenant's contractors and/or subcontractors for
         Landlord's approval, not to be unreasonably withheld.

         (ii)     Four complete sets of plans and specifications properly
         stamped by a registered architect or professional engineer.

         (iii)    A properly executed building permit application form.

         (iv)     Four executed copies of the Insurance Requirements agreement
         in the form attached to these Tenant's Work Requirements as Exhibit G
         from Tenant's contractor and if requested by Landlord from the
         contractor's subcontractors.

         (v)      Contractor's and subcontractor's insurance certificates
         including an indemnity in accordance with the Insurance Requirements
         agreement.

         2.       Landlord will return the following to Tenant:

         (i)      Two sets of plans approved or a disapproval with specific
         comments as to the reasons therefor (such approval or comments shall
         not constitute a waiver of approval of governmental agencies).

         (ii)     Two fully executed copies of the Insurance Requirements
         agreement.

         3.       Tenant shall obtain a building permit from the Building
Department and necessary permits from other governmental agencies. Tenant shall
be responsible for keeping current all permits. Tenant shall submit copies of
all approved plans and permits to Landlord and shall post the original permit on
the Premises prior to the commencement of any work. All work, if performed by a
contractor or subcontractor, shall be subject to reasonable supervision and
inspection by Landlord's Construction Representative. Such supervision and
inspection shall be at Tenant's sole expense and Tenant shall pay Landlord's
reasonable charges for such supervision and inspection not to exceed $5,000.

C.       Requirements and Procedures

         1.       All structural and floor loading requirements shall be subject
to the prior approval of Landlord's structural engineer, not to be unreasonably
withheld.

         2.       All mechanical (HVAC, plumbing and sprinkler) and electrical
requirements shall be subject to the approval, not to be unreasonably withheld,
of Landlord's mechanical and electrical engineers and all mechanical and
electrical work shall be performed by contractors who are engaged by Landlord in
constructing the Building. When necessary, Landlord will require engineering and
shop drawings, which drawings must be approved by Landlord before work is
started, such approval not to be unreasonably withheld. Drawings are to be
prepared by Tenant and all approvals shall be obtained by Tenant.

         3.       Elevator service shall be without charge to Tenant. Prior
arrangements for elevator use shall be made with Building manager by Tenant. No
material or equipment shall

                                       -3-
<PAGE>

be carried under or on top of elevators. If an operating engineer is required by
any union regulations, such engineer shall be paid for by Tenant.

         4.       If shutdown of risers and mains for electrical, HVAC,
sprinkler and plumbing work is required, such work shall be supervised by
Landlord's Construction Representative. No work will be performed in Building
mechanical equipment rooms without Landlord's approval and under Landlord's
supervision.

         5.       Tenant's contractor shall:

         (i)      have a superintendent or foreman on the Premises at all times;

         (ii)     police the job at all times, continually keeping the Premises
         orderly;

         (iii)    maintain cleanliness and protection of all areas, including
         elevators and lobbies;

         (iv)     protect the front and top of all peripheral HVAC units and
         thoroughly clean them at the completion of work;

         (v)      block off supply and return grills, diffusers and ducts to
         keep dust from entering into the Building air conditioning system; and

         (vi)     avoid the disturbance of other tenants.

         6.       If Tenant's contractor is negligent in any of its
responsibilities, Tenant shall be charged for corrective work.

         7.       All equipment and installations must be equal to the standards
generally in effect with respect to the remainder of the Building. Any deviation
from such standards will be permitted only if indicated or specified on the
plans and specifications and approved by Landlord.

         8.       A properly executed air balancing report signed by a
professional engineer shall be submitted to Landlord upon the completion of all
HVAC work.

         9.       Upon completion of the Alterations, Tenant shall submit to
Landlord a permanent certificate of occupancy and final approval by the other
governmental agencies having jurisdiction.

         10.      Tenant shall submit to Landlord a final "as-built" set of
drawings showing all items of the Alterations in full detail.

         11.      Additional and differing provisions in the Lease, if any, will
be applicable and will take precedence.

III.     The following regulations shall be effective with respect to any plans
or specifications that Tenant is required to prepare under the Lease:

         Whenever Tenant shall be required by the terms of the Lease to submit
plans to Landlord in connection with any improvement or alteration to the
Premises, such plans shall include at least the following:

                                       -4-
<PAGE>

         1.       Floor plan indicating location of partitions and doors
                  (details required of partition and door types).

         2.       Location of standard electrical convenience outlets and
                  telephone outlets.

         3.       Location and details of special electrical outlets; e.g.,
                  photocopiers, etc.

         4.       Reflected ceiling plan showing layout of standard ceiling and
                  lighting fixtures. Partitions to be shown lightly with
                  switches located indicating fixtures to be controlled.

         5.       Locations and details of special ceiling conditions, lighting
                  fixtures, speakers, etc.

         6.       Location and specifications of floor covering, paint or
                  paneling with paint colors referenced to standard color
                  system.

         7.       Finish schedule plan indicating wall covering, paint, or
                  paneling with paint colors referenced to standard color
                  system.

         8.       Details and specifications of special millwork, glass
                  partitions, rolling doors and grills, blackboards, shelves,
                  etc.

         9.       Hardware schedule indicating door number keyed to plan, size,
                  hardware required including butts, latchsets or locksets,
                  closures, stops, and any special items such as thresholds,
                  soundproofing, etc. Keying schedule is required.

         10.      Verified dimensions of all built-in equipment (file cabinets,
                  lockers, plan files, etc.)

         11.      Location and weights of storage files.

         12.      Location of any special soundproofing requirements.

         13.      Location and details of special floor areas exceeding 50
                  pounds of live load per square foot.

         14.      All structural, mechanical, plumbing and electrical drawings,
                  to be prepared by the base building consulting engineers,
                  necessary to complete the Premises in accordance with Tenant's
                  plans.

         15.      All drawings to be uniform size (30' x 46') and shall
                  incorporate the standard project electrical and plumbing
                  symbols and be at a scale of 1/8" = 1' or larger.

         16.      All drawings shall be stamped by an architect (or, where
                  applicable, an engineer) licensed in the jurisdiction in which
                  the Property is located and without limiting the foregoing,
                  shall be sufficient in all respects for submission to
                  applicable governmental authorities in connection with a
                  building permit application.

         17.      Landlord's approval of the plans, drawings, specifications or
                  other submissions in respect of any work, addition, alteration
                  or improvement to be undertaken by or on behalf of Tenant
                  shall create no liability or responsibility on the part of
                  Landlord for their completeness, design sufficiency or
                  compliance with

                                       -5-
<PAGE>

                  requirements of any applicable laws, rules or regulations of
                  any governmental or quasi-governmental agency, board or
                  authority.

                                       -6-
<PAGE>

                                    EXHIBIT G
                             CONTRACTOR'S INSURANCE
          (Applicable only if Tenant hires Contractor to Perform Work)

Building:         ____ Winter Street

Tenant:           BGS Systems, Inc.

Premises:         ____ Leasable Square Feet of Space on the First, Second and
                  Third Floors

The undersigned contractor or subcontractor ("Contractor*) has been hired by the
tenant or occupant (hereinafter called "Tenant") of the Building named above or
by Tenant's contractor to perform certain work ("Work") for Tenant in the
Premises identified above. Contractor and Tenant have requested the undersigned
landlord ("Landlord") to grant Contractor access to the Building and its
facilities in connection with the performance of the Work and Landlord agrees to
grant such access to Contractor upon and subject to the following terms and
conditions:

1.       Contractor agrees to indemnify and save harmless the Landlord, Tenant
and their respective officers, employees, agents, members and partners and each
of them, from and with respect to any claims, demands, suits, liabilities,
losses and expenses, including reasonable attorneys' fees, arising out of or in
connection with the Work (and/or imposed by law upon any or all of them) because
of personal injuries, bodily injury (including death at any time resulting
therefrom) and loss of or damage to property, including consequential damages,
whether such injuries to person or property are claimed to be due to negligence
of the Contractor, Tenant, Landlord or any other party entitled to be
indemnified as aforesaid except to the extent specifically prohibited by law
(and any such prohibition shall not void this Agreement but shall be applied
only to the minimum extent required by law).

2.       Contractor shall provide and maintain at its own expense, until
completion of the Work, the following insurance:

(a)      Workmen's Compensation (including coverage for Occupational Disease)
and Employers Liability Insurance covering each and every workman employed in,
about or upon the Work, as provided for in each and every statute applicable to
Workmen's Compensation and Employers' Liability Insurance.

(b)      Comprehensive General Liability Insurance including coverages for
Protective and Contractual liability (to specifically include coverage for the
indemnification clause of this Agreement) for not less than the following
limits:

Personal Injury:

         $3,000,000 per person
         $5,000,000 per
         occurrence

         Property Damage:
         $3,000,000 per occurrence $3,000,000 aggregate

<PAGE>

(c)      Comprehensive Automobile Liability Insurance (covering all owned,
non-owned and/or hired motor vehicles to be used in connection with the Work)
for not less than the following limits:

         Bodily Injury:
         $1,000,000 per person
         $1,000,000 per occurrence

         Property Damage:
         $1,000,000 per occurrence

         Contractor shall furnish a certificate from its insurance carrier or
carriers to the Building office before commencing the Work, showing that it has
compiled with the above requirements regarding insurance and providing that the
insurer will give Landlord ten (10) days' prior written notice of the
cancellation, modification or expiration of any of the foregoing policies.

         3.       Contractor shall require all of its subcontractors engaged in
         the Work to provide the following insurance:

         (a)      Comprehensive General Liability Insurance including Protective
         and Contractual Liability coverages with limits of liability at least
         equal to the limits stated in paragraph 2(b).

         (b)      Comprehensive Automobile Liability Insurance (covering all
         owned, non-owned and/or hired motor vehicles to be used in connection
         with the Work) with limits of liability at least equal to the limits
         stated in paragraph 2(c).

         Upon the request of Landlord, Contractor shall require all of its
subcontractors engaged in the Work to execute an Insurance Requirements
agreement in the same form as this Agreement.

Agreed to and executed this _________ day of ________________, 19___.

         LANDLORD:         880 WINTER STREET, L.L.C.

                           By:      Winter Street OpCo, L.L.C., its managing
                                    member

                                    By:      Leggat McCall Opportunity
                                             Investors, LLC, its managing member

                                             By:      LM Opportunity
                                                      Management LLC, its
                                                      managing member

                                                      By: ______________________
                                                      Name: Eric B. Sheffels
                                                      Title: Vice President

                                       -2-
<PAGE>

         CONTRACTOR:       ________________________________

                           By: ____________________________
                           Name: __________________________
                           Title: _________________________

                                       -3-
<PAGE>

                                    EXHIBIT H
                                     FORM OF

             SUBORDINATION, NON-DISTURBANCE AND ATTORNMENT AGREEMENT
                    [Fleet Bank will be providing this Form]

                                SNDA is Attached

<PAGE>

                                    EXHIBIT H

                      LEASE SUBORDINATION, NON-DISTURBANCE
                     OF POSSESSION AND ATTORNMENT AGREEMENT

         This agreement ("Lease Subordination, Non-Disturbance of Possession and
Attornment Agreement" or "Agreement") is made as of the__________________day of
________________, 1998, among Fleet National Bank, a national banking
association having a place of business at 75 State Street, Boston, Massachusetts
02109 as agent under a Construction and Interim Loan Agreement dated as of
February 10,1998 ("Loan Agreement") among Borrower, Fleet National Bank, and the
other lending institutions which are listed on Schedule 1 annexed to the Loan
Agreement (Fleet National Bank and the other lending institutions which are
listed on Schedule 1 annexed to the Loan Agreement are hereinafter collectively
referred to as "Lenders" and individually as "Lender") and Fleet National Bank,
as agent ("Agent"; which term shall include, if applicable, any other party
substituted for Fleet National Bank as "Agent" under the Loan Agreement), 880
Winter Street, L.L.C., a Delaware limited liability company having a place of
business at 10 Post Office Square, Boston. Massachusetts 02109 ("Landlord" or
"Borrower"), and _________________, a______________________________having a
place of business at_________________________________("Tenant").

                             Introductory Provisions

         A.       Agent is relying on this Agreement as an inducement to Agent
in making and maintaining a loan ("Loan") secured by, among other things, a
Mortgage and Security Agreement dated as of February 10,1998 ("Mortgage") given
by Borrower covering property commonly known as and numbered 880 Winter Street,
Waltham, Massachusetts ("Property"), which Mortgage, including a legal
description of the Property shall be recorded simultaneously herewith. Agent is
also the "Assignee" under an Assignment of Leases and Rents ("Assignment") dated
as of February 10, 1998, from Borrower with respect to the Property which
Assignment shall be recorded simultaneously herewith.

         B.       Tenant is the tenant under that certain lease ("Lease")
dated_____________________, 1998, made with Landlord, covering certain premises
("Premises") at the Property as more particularly described in the Lease and in
the "Notice of Lease" dated______________________, 1998 which shall be recorded
simultaneously herewith.

         C.       Agent requires, as a condition to the making and maintaining
of the Loan, that the Mortgage be and remain superior to the Lease and that its
rights under the Assignment be recognized.

         D.       Tenant requires as a condition to the Lease being subordinate
to the Mortgage that its rights under the Lease be recognized.

<PAGE>

         E.       Agent, Landlord, and Tenant desire to confirm their
understanding with respect to the Mortgage and the Lease.

         NOW, THEREFORE, in consideration of the foregoing, the mutual covenants
and agreements contained herein, and other valuable consideration, the receipt
and adequacy of which are hereby acknowledged, and with the understanding by
Tenant that Agent and Lenders shall rely hereon in making and maintaining the
Loan, Agent and Lenders, Landlord, and Tenant agree as follows:

         1.       Subordination. The Lease and the rights of Tenant thereunder
are subordinate and inferior to the Mortgage and any amendment, renewal,
substitution, extension or replacement thereof and each advance made thereunder
as though the Mortgage, and each such amendment, renewal, substitution,
extension or replacement were executed and recorded, and the advance made,
before the execution of the Lease. Without limiting the foregoing and
notwithstanding any other term or provision of this Agreement, Tenant's rights
with respect to proceeds of insurance and of eminent domain awards are expressly
made subject and subordinate to the rights of Agent, and the disposition of such
proceeds shall be governed by Sections 14.3, 14.4 and 14.5 of the Loan
Agreement, a copy of which Sections is annexed hereto as Exhibit A and
incorporated by reference herein, and the other "Loan Documents" referred to
therein, in all respects.

         2.       Non-Disturbance. So long as Tenant is not in default (beyond
any period expressed in the Lease within which Tenant may cure such default) in
the payment of rent or in the performance or observance of any of the terms,
covenants or conditions of the Lease on Tenant's part to be performed or
observed, (i) Tenant's occupancy of the Premises shall not be disturbed by Agent
in the exercise of any of its rights under the Mortgage during the term of the
Lease, or any extension or renewal thereof made in accordance with the terms of
the Lease, and (ii) Agent will not join Tenant as a party defendant in any
action or proceeding for the purpose of terminating Tenant's interest and estate
under the Lease because of any default under the Mortgage.

         3.       Attornment and Certificates. In the event Agent succeeds to
the interest of Borrower as Landlord under the Lease, or if the Property or the
Premises are sold pursuant to the power of sale under the Mortgage (or by a
deed-in-iieu of foreclosure), Tenant shall attorn to Agent, or a purchaser upon
any such foreclosure sale (or deed-m- lieu), and shall recognize Agent, or such
purchaser, thereafter as the Landlord under the Lease. Such adornment shall be
effective and self-operative without the execution of any further instrument.
Tenant agrees, however, to execute and deliver at any time and from time to
time, upon the request of any holder(s) of any of the indebtedness or other
obligations secured by the Mortgage, or upon request of any such purchaser, (a)
any instrument or certificate which, in the reasonable judgment of such
holder(s), or such purchaser, may be necessary or appropriate in any such
foreclosure proceeding or otherwise to evidence such attornment, and (b) an
instrument or certificate regarding the

                                       -2-
<PAGE>

status of the Lease, consisting of statements, if true (and if not true,
specifying in what respect), (i) that the Lease is in full force and effect,
(ii) the date through which rentals have been paid, (iii) the duration and date
of the commencement of the term of the Lease, (iv) the nature of any amendments
or modifications to the Lease, (v) that no default, or state of facts, which
with the passage of time, or notice, or both, would constitute a default, exists
on the part of Tenant or, to Tenant's knowledge, on the part of Landlord, and
(vi) the dates on which payments of additional rent, if any, are due under the
Lease.

         4.       Limitations. If Agent exercises any of its rights under the
Assignment or the Mortgage, or if Agent shall succeed to the interest of
Landlord under the Lease in any manner, or if any purchaser acquires the
Property, or the Premises, upon or after any foreclosure of the Mortgage, or any
deed in lieu thereof, Agent or such purchaser, as the case may be, shall have
the same remedies by entry, action or otherwise in the event of any default by
Tenant (beyond any period expressed in the Lease within which Tenant may cure
such default) in the payment of rent or in the performance or observance of any
of the terms, covenants and conditions of the Lease on Tenant's part to be paid,
performed or observed that the Landlord had or would have had if Agent or such
purchaser had not succeeded to the interest of the present Landlord. From and
after any such attornment, Agent or such purchaser shall be bound to Tenant
under all the terms, covenants and conditions of the Lease, and Tenant shall,
from and after such attornment to Agent, or to such purchaser, have the same
remedies against Agent, or such purchaser, for the breach of an agreement
contained in the Lease that Tenant might have had under the Lease against
Landlord, if Agent or such purchaser had not succeeded to the interest of
Landlord. Provided however, that Agent or such purchaser shall only be bound
during the period of its ownership, and that in the case of the exercise by
Agent of its rights under the Mortgage, or the Assignment, or any combination
thereof, or a foreclosure, or deed in lieu of foreclosure, all Tenant claims
shall be satisfied only out of the interest, if any, of Agent, or such
purchaser, in the Property, including the interest, if any, of Agent or such
purchaser in any insurance proceeds, condemnation awards, rents, issues or
profits received by Agent or such purchaser on account of the Property
("Property Interests") and, notwithstanding anything to the contrary contained
in the Lease, Agent and such purchaser shall not be (a) liable for any act or
omission of any prior landlord (including the Landlord) provided, however, Agent
shall be responsible for the performance of any landlord obligations under the
Lease which are required to be performed after Agent or such purchaser succeeds
to the interest of Landlord under the Lease; or (b) subject to any offsets,
counterclaims or defenses which Tenant might have against any prior landlord
(including the Landlord); or (c) bound by any rent, percentage rent or
additional rent which Tenant might have paid for more than the then current
rental period to any prior landlord (including the Landlord); or (d) bound by
any amendment or modification of the Lease, or any consent to any assignment or
sublet, made without Agent's prior written consent; or (e) bound by or
responsible for any security deposit, tax, insurance, or other prepaid or
escrowed sums not actually received by Agent; or (f) liable for or incur any
obligation with respect to any breach of warranties or representations of any
nature under the Lease or otherwise including without limitation any warranties
or

                                       -3-
<PAGE>

representations respecting use. compliance with zoning, landlord's title,
landlord's authority, habitability and/or fitness for any purpose, or
possession; or (g) liable for consequential damages or (h) bound to honor
expansion or purchase options under the Lease except as set forth in Section 12,
below. Notwithstanding the foregoing, Tenant specifically acknowledges and
agrees that Agent's liability to Tenant in connection with the Lease is limited
solely to Agent's Property Interests.

         5.       Rights Reserved. Nothing herein contained is intended, nor
shall it be construed, to abridge or adversely affect any right or remedy of:
(a) the Landlord under the Lease, or any subsequent Landlord, against the Tenant
in the event of any default by Tenant (beyond any period expressed in the Lease
within which Tenant may cure such default) in the payment of rent or in the
performance or observance of any of the terms, covenants or conditions of the
Lease on Tenant's part to be performed or observed; or (b) the Tenant under the
Lease against any prior landlord (including the Landlord) in the event of any
default by such Landlord to pursue claims against such Landlord whether or not
such claim is barred against Agent or a subsequent purchaser.

         6.       Notice and Right to Cure. Tenant agrees to provide Agent with
a copy of each notice of default given to Landlord under the Lease, at the same
time as such notice of default is given to the Landlord, and that, in the event
of any default by the Landlord under the Lease, Tenant will take no action to
terminate the Lease (a) if the default is not curable by Agent (so long as the
default does not interfere with Tenant's use and occupation of the Premises), or
(b) if the default is curable by Agent, unless the default remains uncured for a
period of thirty (30) days after written notice thereof shall have been given,
postage prepaid, to Landlord at Landlord's address, and to Agent at the address
provided in Section 7 below; provided however, that if any such default is such
that it reasonably cannot be cured within such thirty (30) day period, such
period shall be extended for such additional period of time as shall be
reasonably necessary (including, without limitation, a reasonable period of time
to obtain possession of the Property and to foreclose the Mortgage), if Agent
gives Tenant written notice within such thirty (30) day period of Agent's
election to undertake the cure of the default and if curative action (including,
without limitation, action to obtain possession and foreclose) is instituted
within a reasonable period of time and is thereafter diligently pursued. Unless
Agent has provided Tenant with such written notice of Agent's election to
undertake a cure of a default as provided above, Agent shall have no obligation
to cure any default under the Lease.

         7.       Notices. Any notice or communication required or permitted
hereunder shall be in writing, and shall be given or delivered: ( i) by United
States mail, registered or certified, postage fully prepaid, return receipt
requested, or (ii) by recognized courier service or recognized overnight
delivery service; and in any event addressed to the party for which it is
intended at its address set forth below:

                                       -4-
<PAGE>

         To Agent:         Fleet National Bank
                           75 State Street
                           Boston, Massachusetts 02109
                           Attention: Michael J. Sleece

         with a copy to:   Goulston & Storrs, P.C.
                           400 Atlantic Avenue
                           Boston, Massachusetts 02110
                           Attention: Michael J. Haroz, Esq.

         To Tenant:        _________________________________
                           _________________________________
                           _________________________________

         with a copy to:   _________________________________
                           _________________________________
                           _________________________________

or such other address as such party may have previously specified by notice
given or delivered in accordance with the foregoing. Any such notice shall be
deemed to have been given and received on the date delivered or tendered for
delivery during normal business hours as herein provided.

         8.       No Oral Change. This Agreement may not be modified orally or
in any manner than by an agreement in writing signed by the parties hereto or
their respective successors in interest.

         9.       Successors and Assigns. This Agreement shall inure to the
benefit of and be binding upon the parties hereto, their respective heirs,
personal representatives, successors and assigns (including, without limitation,
holders by assignment or participation of interests in the Loan), and any
purchaser or purchasers at foreclosure of the Property or any portion thereof,
and their respective heirs, personal representatives, successors and assigns.

         10.      Payment of Rent To Agent. Tenant acknowledges that it has
notice that the Lease and the rent and all sums due thereunder have been
assigned to Agent as part of the security for the Obligations secured by the
Mortgage. In the-event Agent notifies Tenant of a default under the Loan and
demands that Tenant pay its rent and all other sums due under the Lease to Agent
(the "Notification"), Tenant agrees that it will honor such demand and pay its
rent and all other sums due under the Lease to Agent, or Agent's designated
agent, until otherwise notified in writing by Agent. Borrower unconditionally
authorizes and directs Tenant to make rental payments directly to Agent
following receipt of such notice and further agrees that Tenant may rely upon
such notice without any obligation to farther inquire as to whether or not any
default exists under the Mortgage or

                                       -5-
<PAGE>

the Assignment, and that Borrower shall have no right or claim against Tenant
for or by reason of any payments of rent or other charges made by Tenant to
Agent following receipt of such notice. Tenant and Borrower each acknowledge
Agent's right to collect rents and other sums under the Lease, as set forth
above, and Agent acknowledges that from and after the date on which Agent has
provided the Notification to Tenant Agent shall be bound to Tenant under the
terms, covenants and conditions of the Lease, including, without limitation, the
covenant to furnish building services and otherwise operate the Property as more
particularly described in the Lease.

         11.      No Amendment or Cancellation of Lease. So long as the Mortgage
remains undischarged of record, except as expressly permitted by the Lease,
Tenant shall not amend, modify, cancel or terminate the Lease, or consent to an
amendment, modification, cancellation or termination of the Lease, or agree to
subordinate the Lease to any other mortgage, without Agent's prior written
consent in each instance.

         12.      Options. With respect to any options for additional space
provided to Tenant under the Lease, Agent agrees to recognize the same if Tenant
is entitled thereto under the Lease after the date on which Agent succeeds as
Landlord under the Lease by virtue of foreclosure or deed in lieu of foreclosure
or Agent takes possession of the Premises; provided, however, Agent shall not be
responsible for any acts of any prior landlord under the lease, or the act of
any tenant subtenant or other party which prevents Agent from complying with the
provisions hereof and Tenant shall have no right to cancel the Lease or to make
any claims against Agent on account thereof.

         With respect to any options in the Lease or otherwise providing Tenant
with rights to purchase the Property or interests therein, such options shall be
subordinate to the Mortgage and shall not apply to any foreclosure or
deed-in-lieu of foreclosure.

         13.      Captions. Captions and headings of sections are not parts of
this Agreement and shall not be deemed to affect the meaning or construction of
any of the provisions of this Agreement.

         14.      Counterparts. This Agreement may be executed in several
counterparts each of which when executed and delivered is an original, but all
of which together shall constitute one instrument.

         15.      Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the Commonwealth of Massachusetts.

         16.      Parties Bound. The provisions of this Agreement shall be
binding upon and inure to the benefit of Tenant, Agent and Lenders and Borrower
and their respective successors and assigns; provided, however, reference to
successors and assigns of Tenant shall not constitute a consent by Landlord or
Borrower to an assignment or sublet by

                                       -6-
<PAGE>

Tenant, but has reference only to those instances in which such consent is not
required pursuant to the Lease or for which such consent has been given.

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed as of the date first above written.

                                   AGENT:

                                   FLEET NATIONAL BANK,
                                   a national banking association

                                   By: _________________________________
                                       Name:
                                       Title:

                                   Date executed by Agent: _____________

                                   TENANT:

                                   _____________________________________
                                   a ___________________________________

                                   By: _________________________________
                                       Name:
                                       Title:

                                   Date executed by Tenant: ____________

ATTEST:

________________________________
Name:
Title:

                                       -7-
<PAGE>

                          COMMONWEALTH OF MASSACHUSETTS
                    , ss.                                ,19

         Then personally appeared before me___________________________________,
a _____________________ of Fleet National Bank, a national banking association,
and acknowledged the foregoing to be his free act and deed and the free act and
deed of said Fleet National Bank.

                                        _______________________________
                                        Notary Public
                                        My Commission Expires:

         880 Winter Street L.L.C., as Landlord under the Lease, and Borrower
under the Mortgage and Security Agreement, the Loan Agreement and the other Loan
Documents, agrees for itself and its successors and assigns that:

         1.       The above agreement does not:

                  (a)      constitute a waiver by Agent of any of its rights
                           under the Mortgage and Security Agreement or any of
                           the other Loan Documents; or

                  (b)      in any way release Borrower from its obligations to
                           comply with the terms, provisions, conditions,
                           covenants and agreements and clauses of the Mortgage
                           and Security Agreement and other Loan Documents;

         2.       The provisions of the Mortgage and Security Agreement remain
                  in full force and effect and must be complied with by
                  Borrower;

         3.       Tenant shall have the right to rely on any notice or request
                  from Agent which directs Tenant to pay rent to Agent without
                  any obligation to inquire as to whether or not a default
                  exists and notwithstanding any notice from or claim of
                  Borrower to the contrary. Borrower shall have no right or
                  claim against Tenant for rent paid to Agent after Agent so
                  notifies Tenant to make payment of rent to Agent; and

         4.       The Borrower shall be bound by all of the terms, conditions
                  and provisions of the foregoing Agreement in all respects.

                                       -8-
<PAGE>

Executed and delivered as a sealed instrument as of the____________day
of___________, 1998.

                                   BORROWER:

                                   880 WINTER STREET, L.L.C., a
                                   Delaware limited liability company

                                   By: Winter Street OpCo, L.L.C.,
                                       its Managing Member

                                       By:  Leggat McCall Opportunity Investors,
                                            LLC, its Managing Member

                                            By: LM Opportunity Management, LLC,
                                                its Managing Member

                                                By: ____________________________
                                                    Name:
                                                    Title:
                                                    Hereunto duly authorized

                                       Date executed by Borrower:_________, 1998

                          COMMONWEALTH OF MASSACHUSETTS

__________, ss.                                              _________ __, ,1998

         Then personally appeared before me the above-named____________________,
the __________ of LM Opportunity Management, LLC, the Managing Member of Leggat
McCall Opportunity Investors, LLC, the Managing Member of Winter Street OpCo,
L.L.C., the Managing Member of 880 Winter Street, L.L.C. (the Borrower described
above) and acknowledged the foregoing instrument to be such person's free act
and deed and the free act and deed of such Borrower.

                                           ________________________________
                                           ____________, Notary Public
                                           My Commission Expires:

                                       -9-
<PAGE>

                                    Exhibit A

                     Loan Agreement - Sections 14.3 - 14.5

         14.3     Payment and Application of Insurance Proceeds. All proceeds of
insurance shall be paid to Agent and, at Agent's option, be applied to
Borrower's Obligations or released, in whole or in part, to pay for the actual
cost of repair, restoration, rebuilding or replacement (collectively, "Cost To
Repair"). If the Cost To Repair does not exceed $100,000.00 and no Event of
Default has occurred, Agent shall exercise its option to release so much of the
insurance proceeds as may be required for Borrower to pay for the actual Cost to
Repair in a commercially reasonable manner. If the Cost to Repair is $100,000
or more, Agent shall also exercise its option to release so much of the
insurance proceeds as may be required to pay for the actual Cost To Repair if:

                           (i)      in Agent's good faith judgment such proceeds
                  together with any additional funds as may be deposited with
                  and pledged to Agent are sufficient to pay for the Cost To
                  Repair;

                           (ii)     in Agent's good faith judgment the Repair
                  Work is likely to be completed prior to the Maturity Date; and

                           (iii)    no Event of Default has occurred under the
                  Loan Documents.

         14.4     Conditions To Release of Insurance Proceeds. If Agent elects
or is required to release insurance proceeds and the Cost to Repair is $100,000
or more, Agent may impose reasonable conditions on such release which shall
include, but not be limited to, the following:

                  14.4.1   Prior To Substantial Completion. If the Casualty
         occurs prior to Substantial Completion of the Improvements,
         satisfaction of all conditions precedent to Loan Advances set forth in
         Sections 6,7.1 and 7.2 and compliance with all construction
         requirements of this Agreement.

                  14.4.2   After Substantial Completion. If the Casualty occurs
         after Substantial Completion of the Improvements:

                           (i)      Prior written approval by Agent, which
                  approval shall not be unreasonably withheld or delayed of
                  plans, specifications, cost estimates, contracts and bonds for
                  the restoration or repair of the loss or damage;

                                      -10-
<PAGE>

                           (ii)     Waivers of lien, architect's certificates,
                  contractor's sworn statements and other evidence of costs,
                  payments and completion as Agent may reasonably require;

                           (iii)    If the Cost To Repair does not exceed
                  $100,000.00, the funds to pay therefor shall be released to
                  Borrower. Otherwise, funds shall be released upon final
                  completion of the Repair Work, unless Borrower requests
                  earlier funding, in which event partial monthly disbursements
                  equal to 90% of the value of the work completed or, if the
                  applicable contract is on a cost plus basis, then 90% of the
                  costs of the work completed if such cost is less than the
                  value thereof shall be made prior to final completion of the
                  repair, restoration or replacement and the balance of the
                  disbursements shall be made upon full completion and the
                  receipt by Agent of satisfactory evidence of payment and
                  release of all liens;

                           (iv)     Determination by Agent that the undisbursed
                  balance of such proceeds on deposit with Agent, together with
                  additional funds deposited for the purpose, shall be at least
                  sufficient to pay for the remaining Cost To Repair, free and
                  clear of all liens and claims for lien;

                           (v)      All work to comply with the standards,
                  quality of construction and Legal Requirements applicable to
                  the construction of the Improvements; and

                           (vi)     the absence of any Event of Default under
                  any Loan Documents.

         14.5     Taking. If there is any condemnation for public use of the
Property or of any Collateral, the awards on account thereof shall be paid to
Agent and shall be applied to Borrower's Obligations, or at Agent's discretion
released to Borrower. If, in the case of a partial taking or a temporary taking,
in the sole judgment of Agent the effect of such taking is such that there has
not been a material and adverse impairment of the viability of the Project or
the value of the Collateral, so long as no Default exists Agent shall release
awards on account of such taking to Borrower if such awards are sufficient (or
amounts sufficient are otherwise made available) to repair or restore the
Property to a condition reasonably satisfactory to Agent and such partial or
temporary taking shall not be deemed to violate the provisions of Section 9.6.1.

                                      -11-
<PAGE>

                                    EXHIBIT I

                             BASE BUILDING CONDITION

                         Waltham Woods Corporate Center
                      Description of Tenant Shell Condition

         The following is to be delivered at Landlord's expense unless otherwise
provided herein.

A)       Floors

         1)       Landlord's base building shell contractor will leave the
                  entire shell space broom cleaned and ready for minor leveling
                  material where necessary to accommodate Tenant fit-ups. Minor
                  floor prep work will be done by the tenant's carpet contractor
                  as part of the tenant build out. Flash patching to address
                  1/4" variances or more to be performed by Landlord's
                  Contractor.

B)       Windows

         1)       All building standard perimeter windows will be cleaned on the
                  inside.

         2)       All building standard perimeter window blinds will be
                  installed and left in place for Tenant's use.

         3)       Building standard window sills will be steamed beech stained
                  to match Building finish, furnished and installed.

C)       Columns

         1)       Columns are to be delivered with drywall enclosures, taped,
                  and sanded ready to accept paint by Tenant.

D)       Exterior Walls

         1)       All exterior walls will be insulated, covered with drywall,
                  taped, and sanded ready to receive new finishes by the Tenant.
                  Installation of perimeter power, data & comm to be coordinated
                  with Landlord.

E)       Interior Common Area Walls or Corridor Demising Walls

         1)       All interior common area walls and corridor demising walls
                  will be sheet rocked, taped, and sanded ready for Tenant
                  vacant side. The corridor side will be finished with Building
                  standard corridor finishes.

F)       Ceilings

         1)       The ceiling in the shell space will be exposed structural
                  steel and metal decking ready to receive the Tenant's ceiling
                  system.

<PAGE>

G)       HVAC

         1)       The Landlord's shell contractor will provide medium pressure
                  duct and interior VAV boxes and perimeter fan-powered VAV
                  boxes with DDC thermostat in a temporary location in the
                  vacant shell spaces. All work downstream of the VAV boxes
                  including sheet metal, flex ductwork, grilles and diffusers,
                  exhaust fans, balancing and connecting into the energy
                  management system Will be part of Tenant build out.

H)       Fire Protection

         1)       The entire Building will be sprinklered with sprinkler heads
                  in the vacant shell space left in the upright condition spaced
                  approximately 12' x 14' on center. Landlord will be
                  responsible for dropping these heads into the space initially
                  constructed for 10/15/98 occupancy.

I)       Electrical

         1)       Base Building

                  (a)      The electrical service to the Building is provided by
                           a pad mounted transformer. The secondary service
                           characteristics are 277/480 volts, three (3) phase,
                           four (4) wire, 60 Hertz, terminating at the 4000 Amp
                           main switchboard in the basement electrical room.

                  (b)      Each floor is served with Tenant distribution panels
                           served from a 277/480 volt vertical buss riser.

         2)       Tenant

                  Tenant distribution panels (2 double tub 225 amp 110/208 bulb
                  panels per electric closet) are to provide power for the
                  Tenant lighting, power and VAV boxes. Tenant light and power
                  will he distributed to each floor at 8.0 watts per square
                  foot. An additional 2.0 watts per square foot will be
                  available for Tenant lights and power at the main switchboard
                  in the basement.

                  Common area VAV's will be wired to the house panels. Tenant
                  VAV's will need to be connected to the Tenant panels for
                  metering.

         3)       Base/Tenant

                  Electrical metering is being provided through a check meter
                  system installed by the Landlord. Meter hook up by the Tenant.

         4)       Base /Tenant

                  The fire alarm system for the Building will meet the "ADA"
                  requirements. Building common areas are complete. Tenant to
                  install horn/strobes with their build out, the cost of which
                  will be capped at $250/unit. Landlord shall reimburse Tenant
                  for costs in excess of $250/unit.

                                       -2-
<PAGE>

         5)       Tenant

                  Telephone closets are provided on each floor for distribution.

J)       Building Amenities

         1)       Cafeteria

                  Full regular type service cafeteria serving hot and cold food
                  (breakfast and lunch only) in accordance with other first
                  class suburban office parks in the area. Available seating for
                  one hundred fifty (150) people. Facility available for
                  catering upon request.

         2)       Health Club

                  Unmanned facility with aerobic equipment, carpeted floor,
                  locker/shower rooms for men and women.

         3)       Conference Room

                  Shared conference room facility of approximately 24 feet by 35
                  feet or approximately eight hundred fifty (850) square feet,
                  with facilities for audio/visual conferencing, available on a
                  reservation basis by appointment for a nominal charge, not to
                  exceed fifty dollars ($50.00) per hour exclusive of
                  audio/visual conferencing charges.

                                       -3-
<PAGE>

                                    EXHIBIT J

                   BUILDING STANDARD MATERIALS/SPECIFICATIONS

A.       DOORS, FRAMES & HARDWARE

         TENANT SUITE ENTRY AND EGRESS DOORS

         Solid core European steamed beech veneer doors in a pressed metal frame
         with building standard hardware. Tenant may install a curved entry with
         glass doors and a full height glass wall so long as Tenant uses the
         same wood treatment, encasement and detail as in the Base Building.
         Door shall be full height 3' 0 x 8' 0" x 1' 3/4".

         TENANT ENTRY DOOR FRAME

         Solid wood European steamed beech frame with 1' 6" x 8' 0" sidelight.

         INTERIOR DOOR

         Solid core European steamed beech veneer doors in & pressed metal frame
         with building standard hardware. Door shall be full height 3' 0 x 8' 0"
         x 1' 3/4".

         STAIN

         Stain veneer to match architect's (base building) sample.

         ENTRY AND EGRESS DOOR HARDWARE

         Schlage L-Series type 07 lever - full mortise, lever dead latch lockset
         with surface mounted ADA closer, two pair of heavy weighted hinges,
         Ives door stop and silencer. Metal shall be US 26 Polished Chrome or
         US32 polished stainless steel.

         INTERIOR DOOR HARDWARE

         Lever hardware with two pair of heavy weight hinges, Ives door stop and
         silencer.

B.       BUILDING SAFETY

         FIRE PROTECTION

         Hydraulically designed, light hazard wet sprinkler system throughout
         all common and tenant areas. Heads shall be concealed phantom type
         heads recessed in ceiling and centered in the 2' x 2' ceiling tile.

         The underground garage will be protected by a dry type sprinkler
         system.

         SMOKE DETECTORS, HEAT DETECTORS, REMOTE LED's

         Smoke or heat detectors will be installed, where required using CPD-ID
         Module 301-ID by Fire Control Instruments.

         FIRE ALARM HORN/STROBE

         Fire alarm strobes will be installed, where required.

<PAGE>

                                       -2-

C.       CEILING

         ACOUSTICAL TILE

         Acoustic ceiling tile shall be VSG Acoustical Frost 414 with 2' x 2' x
         5/8" thick tegular edge

         SUSPENSION GRID

         Grid shall be Chicago Metallic 716 white ceiling grid

         CEILING HEIGHTS

         13' 8" - slab to slab

         9' 6" - finished ceiling height in tenant space

         LIGHTING

         2' x 4', 18 cell, 3 lamp, 277 volt, florscent parabolic fixture with
         electronic ballast and T- 8 lamps and return air baffles. Lighting will
         provide 50 foot candles 30" above finished floor.

D.       FLOOR COVERINGS

         CARPET

         Cut pile option: 32 ounce "Cyprus Point IV" by Shaws; or Loop pile
         option: 28 ounce "Colonial" by Shaws

         VINYL COMPOSITION TILE

         12" x 12" tile by Armstrong Standard Excelon

         BASE

         4" high resilient base by Nafco or Roppe

E.       PARTITIONS

         DEMISING PARTITION

         Framed with 3 5/8", 25 gage metal studs on 16" centers. Partitions
         shall have one layer of 5/8" gypsum wall board, each side, taped and
         sanded. Cavity shall have mineral BATT insulation and meet or exceed
         the Underwriters Laboratory Design U448. Partition shall extend from
         floor to deck and be sealed, top and bottom.

         INTERIOR PARTITION

         Framed with 2 1/2", 20 gage metal studs or 3 5/8", 25 gage metal studs
         on 16" centers. Partitions shall have one layer of [5/8"] gypsum wall
         board on each side, taped and sanded. Framing and gypsum board shall
         extend from the floor to 6" above the ceiling.

         With respect to all materials provided for in this Exhibit J, Tenant
         may substitute materials of its selection subject to Landlord's prior
         approval in writing, such approval not to be unreasonably withheld.

<PAGE>

                                    EXHIBIT K

                             CLEANING SPECIFICATIONS

1.       CLEANING.

A.       OFFICE AREA

         Daily on Business Days:

         1.       Empty and clean all waste receptacles and ash trays and remove
                  waste material from the Premises; wash receptacles as
                  necessary.

         2.       Sweep and dust mop all carpeted areas using a dust treated
                  mop.

         3.       Vacuum all rugs and carpeted areas.

         4.       Hand dust and wipe clean with treated cloths all horizontal
                  surfaces including furniture, office equipment, window sills,
                  door ledges, chair rails, and convector tops, within normal
                  reach.

         5.       Wash clean all water fountains.

         6.       Remove and dust under all desk equipment and telephones and
                  replace same.

         7.       Wipe clean all brass and other bright work.

         8.       Hand dust all grill work within normal reach.

         9.       Upon completion of cleaning, all lights will be turned off and
                  doors locked, leaving the Premises in an orderly condition.

         Weekly:

         1.       Dust coat racks, and the like.

         2.       Remove all finger marks from private entrance doors, light
                  switches and doorways.

         Quarterly:

         Render high dusting not reached in daily cleaning to include:

         1.       Dusting all pictures, frames, charts, graphs, and similar wall
                  hangings.

         2.       Dusting all vertical surfaces, such as walls, partitions,
                  doors, and ducts.

         3.       Dusting all pipes, ducts and high moldings.

         4.       Dusting all Venetian blinds.

<PAGE>

                                       -2-

B.       LAVATORIES

Daily on Business Days:

         1.       Sweep and damp mop floors.

         2.       Clean all mirrors, powder shelves, dispensers and receptacles,
                  bright work, flushometers, piping, and toilet seat hinges.

         3.       Wash both sides of all toilet seats.

         4.       Wash all basins, bowls, and urinals.

         5.       Dust and clean all powder room fixtures.

         6.       Empty and clean paper towel and sanitary disposal receptacles.

         7.       Remove waste paper and refuse.

         8.       Refill tissue holders, soap dispensers, towel dispensers,
                  vending sanitary dispensers; materials to be furnished by
                  Landlord.

         9.       A sanitizing solution will be used in all lavatory cleaning.

         Monthly:

         1.       Machine scrub lavatory floors.

         2.       Wash all partitions and tile walls in lavatories.

C.       MAIN LOBBY, ELEVATORS, BUILDING EXTERIOR AND CORRIDORS

         Daily on Business Days:

         1.       Sweep and wash all floors.

         2.       Wash all rubber mats.

         3.       Clean elevators, wash or vacuum floors, wipe down walls and
                  corridors.

         4.       Spot clean any metal work inside lobby.

         5.       Spot clean any metal work surrounding Building entrance doors.

         Monthly:

         All resilient tile floors in public areas to be treated equivalent to
         spray buffing.

D.       EXTERIOR WINDOWS

         Biannually:

         Wash exterior windows.

<PAGE>

                                    EXHIBIT L

                                    GUARANTY

         FOR VALUE RECEIVED, and in consideration for and as an inducement to
880 Winter Street, L.L.C., a Delaware limited liability company (hereinafter the
"Landlord"), with a mailing address c/o Leggat McCall Properties, L.P., 10 Post
Office Square, Boston, Massachusetts 02109, to enter into, execute and deliver
that certain Lease dated July______, 1998 (the "Lease") with BGS Systems, Inc.,
a Massachusetts corporation (hereinafter the "Tenant"), covering certain
premises within the building numbered 880 Winter Street, Waltham, Massachusetts,
as more particularly described in the Lease, the undersigned, BMC Software,
Inc., a Delaware corporation (hereinafter the "Guarantor"), with a mailing
address at 2101 CityWest Boulevard, Houston, TX 77042, hereby unconditionally
guarantees to the Landlord the prompt payment by Tenant of all Basic Rent and
Additional Charges (as defined in the Lease) under the Lease within the grace
periods therein set forth, if any, and hereby further guarantees the full and
timely performance and observance of all the other covenants, conditions and
agreements therein provided to be performed and observed by Tenant within the
grace periods therein set forth, if any, and the Guarantor hereby covenants and
agrees to and with Landlord that if Tenant, or its successors or assigns,
defaults in the payment of any Basic Rent or Additional Charges, or if Tenant,
its successors or assigns, should default in the performance and observance of
any of the covenants, terms, conditions and agreements contained in the Lease
beyond any applicable grace period therein set forth, the Guarantor, in each and
every instance, shall and will forthwith pay the Basic Rent and Additional
Charges in arrears and shall and will forthwith faithfully perform and fulfill
all of such covenants, terms, conditions and agreements to which Tenant is in
default, and will forthwith pay to Landlord all damages, including reasonable
attorneys' fees, that may arise as a consequence of any Default of Tenant under
the Lease to the extent that the same would be recoverable against Tenant at
law, and all reasonable attorneys' fees and disbursements incurred by Landlord
in the enforcement of this Guaranty.

         This Guaranty is an absolute and unconditional guaranty of payment and
performance and not only collection. It shall be enforceable against Guarantor
without the necessity of any suit or proceedings on Landlord's part of any kind
or nature whatsoever against Tenant or its successors or assigns, and without
the necessity of any notice of non-payment, non-performance or non-observance or
any notice of acceptance of this Guaranty or of any notice or demand to which
Guarantor otherwise might be entitled, all of which Guarantor hereby expressly
waives; and Guarantor expressly agrees that the validity of this Guaranty and
the obligations of Guarantor hereunder shall in no wise be terminated, affected,
diminished or impaired by reason of the granting by Landlord of any indulgences
to Tenant or by reason of the assertion or the failure to assert by Landlord
against Tenant, or against Tenant's successors or assigns, of any of the rights
or remedies reserved to Landlord pursuant to the provisions of the Lease, or by
the relief of Tenant from any of Tenant's obligations under said Lease by
operation of law or otherwise (including, but without limitation, the rejection
of the said Lease in connection with proceedings under the bankruptcy laws now
or hereafter enacted); the Guarantor hereby waiving all suretyship defenses.

         The Guarantor further covenants and agrees that this Guaranty shall be
a continuing guaranty and shall remain and continue in full force and effect as
to any renewal, modification or extension of, or exercise of any expansion
option or right of first offer under said Lease, whether or not the Guarantor
shall have received any notice of or consented to such renewal, modification or
extension or exercise of expansion option or right of first offer. The Guarantor
further agrees that its liability under this Guarantee shall be primary and
that, in any right of action which shall accrue to Landlord under said Lease,
Landlord may, at Landlord's option,

<PAGE>

                                       -2-

proceed against the Guarantor and Tenant, jointly or severally, and may proceed
against the Guarantor without having commenced any action against or having
obtained any judgment against Tenant.

         The Guarantor further represents to Landlord, as an inducement for
Landlord to enter into, execute and deliver said Lease, that the Guarantor owns
all of the entire outstanding capital stock of Tenant, that the execution and
delivery of this Guaranty is not in contravention of its Charter or By-Laws or
applicable Sate laws, and has been duly authorized by its Board of Directors.

         It is agreed that the failure of Landlord to insist in any one or more
instances upon a strict performance or observance of any of the terms,
provisions or covenants of the Lease or to exercise any right therein contained
shall not be construed or deemed to be a waiver or relinquishment for the future
of such term, provision, covenant or right, but the same shall continue and
remain in full force and effect. Receipt by Landlord of Rent or Additional
Charges with knowledge of the breach of any provision of the Lease shall not be
deemed a waiver of such breach.

         No subletting, assignment or other transfer of the Lease, or any
interest therein, shall operate to extinguish or diminish the liability of the
Guarantor under this Guaranty; and, wherever reference is made to the liability
of Tenant named in the within Lease, such reference shall be deemed likewise to
refer to Guarantor.

         The Guarantor covenants to provide Landlord with the notice of any
Security Deposit Event (as defined in the Lease) at the times and in the manner
set forth in Section 14.17 of the Lease and to cause Tenant to provide any
security deposit required in connection with any such Security Deposit Event as
provided in Section 14.17. The Guarantor covenants to deliver, or cause the
Tenant to deliver, to the Landlord its financial statements in the manner and at
the times required by Section 14.23 of the Lease.

         The Guarantor agrees that whenever at any time or from time to time
Guarantor shall make any payment to Landlord or perform or fulfill any covenant,
term, condition or agreement hereunder on account of the liability of Guarantor
under this Guaranty, Guarantor will notify Landlord in writing that such payment
or performance, as the case may be, is for such purpose. No such payment or
performance by Guarantor pursuant to any provision hereof shall entitle
Guarantor by subrogation or otherwise to the rights of Landlord to any payment
by Tenant or to the property of Tenant, except after payment of all sums or
fulfillment of all covenants, terms, conditions or agreements then to be paid or
performed by Tenant or its successors or assigns under the Lease.

         The Guarantor and Landlord agree that each will, at any time, and from
time to time, within ten (10) calendar days following written request by the
other, execute, acknowledge and deliver to the party requesting the same a
statement certifying that this Guaranty is unmodified and in full force and
effect (or if there have been modifications, that the same is in full force and
effect as modified and setting forth such modification), and Landlord shall also
state in such certificate whether, as of the date thereof, Guarantor has paid
and performed such of its obligations thereunder which Guarantor has theretofore
been notified to pay and perform. Guarantor and Landlord agree that such
certificate may be relied upon by anyone holding or proposing to acquire any
interest in the Premises (as defined in the Lease) from or through Landlord or
Tenant, or by any mortgagee or prospective mortgagee of the Premises or of the
land and building of which the Premises are a part.

<PAGE>

                                       -3-

         Any notice, demand or other communication (herein collectively a
"Notice") given hereunder or in connection herewith shall be in writing and
shall have been deemed to have been properly given, rendered or made, when hand
delivered or deposited with a nationally recognized overnight courier or with
the United States Post Office, by certified mail, return receipt requested,
addressed to Landlord or Guarantor, at the respective addresses for Landlord and
Guarantor hereinabove set forth in this instrument of Guaranty. Either Landlord
or Guarantor may, by Notice as aforesaid, designate a different address or
attention designation for Notices intended for it. Such Notice shall be given,
and shall be deemed to have been given and received, when so hand delivered
(against a signed receipt) or three (3) days after such deposit of such Notice
by certified mail enclosed in a security closed post-paid wrapper, in a United
States Post Office, or one (1) day after such deposit of such Notice with a
nationally recognized overnight courier; and in the case of failure to deliver
by reason of changed address of which no Notice was given or refusal to accept
delivery, as of the date of such failure as indicated on the return receipt or
by notice of the post office department or such nationally recognized courier.

         As a further inducement to Landlord to enter into, execute and deliver
the Lease, and in consideration thereof, Landlord and Guarantor covenant and
agree that in any action or proceeding brought on, under, or by virtue of this
Guaranty, Landlord and Guarantor shall and do hereby waive trial by jury.

         It is further agreed that all of the terms and provisions hereof shall
be binding upon and inure to the benefit of Landlord and Guarantor, and their
respective legal representatives, successors and assigns.

         Initially capitalized words not defined in this Guaranty shall have the
meanings set forth in the Lease.

         This Guaranty shall be governed by, and construed and enforced in
accordance with, the law of the Commonwealth of Massachusetts, as the same may
from time to time exist.

         IN WITNESS WHEREOF, Guarantor has caused this instrument to be executed
in its corporate name by its duly authorized representative, and its corporate
seal to be affixed hereto, this________________day of July, 1998.

                                   BMC SOFTWARE, INC.

                                   By: _________________________________________
                                   Name: _______________________________________
                                   Title: ______________________________________

                                   Hereunto duly authorized
                                                                [Corporate Seal]

Attest   _______________________________
Name:    _______________________________

         (Secretary)(Assistant Secretary)

<PAGE>

                                       -4-

STATE OF _________________________)
                                  )  ss.
COUNTY OF ________________________)

         On this__________ day of __________, 1998 before me personally appeared
__________________, who, being by me duly sworn, did say that he (she) is
_____________________of BMC Software, Inc., a Delaware corporation, that (he)
(she) knows the seal of said Corporation and that the seal affixed to said
instrument is the corporate seal of said Corporation, and that said instrument
was signed and sealed in behalf of said Corporation by authority of its Board of
Directors, and said________________________________ acknowledged said instrument
to be the free act and deed of said Corporation.

                                   Name: _______________________________________

                                   Notary Public in the State of _______________

                                   My commission expires:_______________________

                                   [Notarial Seal]

<PAGE>

                                    EXHIBIT M

                              HVAC SPECIFICATIONS

Subject to the provisions of Section 7.4, Landlord will furnish air conditioning
and heating during Business Hours to the Premises and Building common areas.

The Building standard heating, ventilating and air conditioning system shall
perform to the following standards:

<TABLE>
<S>      <C>                        <C>
(1)      Summer Temperature:        88 degrees Fahrenheit dry bulb and 74
                                    degrees Fahrenheit wet bulb outside; 62
                                    degrees Fahrenheit coincident wet bulb
                                    inside (1 1/2% coincidence, ASHRAE Guide to
                                    Maintain an Inside Temperature of 78"
                                    degrees Fahrenheit dry bulb, plus or minus
                                    3%).
--------------------------------------------------------------------------------
(2)      Winter Temperature:        9 degrees Fahrenheit dry bulb outside; 72
                                    degrees Fahrenheit dry bulb inside, plus or
                                    minus 3%.

--------------------------------------------------------------------------------

(3)      Space Ventilation          20 cubic feet per minute/for a maximum of
         Criteria:                  one (1) person per 150 square feet of Net
                                    Rentable Area on a per floor basis (ASHRAE
                                    standard 62-1981R).
--------------------------------------------------------------------------------
</TABLE>

<PAGE>

                                    EXHIBIT N

                                SIGNAGE LOCATIONS

                          [to be provided by Landlord]

<PAGE>

                                    EXHIBIT O

                               LIST OF COMPETITORS

1.       Computer Associates International, Inc.

2.       Compuware Corporation

3.       Envive Corporation

4.       Net IQ Sdn Bhd

5.       Platinum Technologies, Inc.

6.       Tivoli Systems, Inc.

7.       NEON Systems, Inc.

<PAGE>

                                    EXHIBIT P

         [RESTRICTION AGAINST LEASE ASSIGNMENT OR SPACE SUBLETTING TO BE
           INCLUDED BY LANDLORD IN TENANT LEASES OF THE COMPLEX TO THE
         EXTENT APPLICABLE UNDER THE PROVISIONS OF SECTION 5.1(c) OF THE
                    LEASE OF WHICH THIS EXHIBIT P IS A PART]

         For so long as BGS Systems, Inc. ("BGS") or an Affiliate is in actual
occupancy of at least 75% of its Premises Rentable Area in the Complex, Tenant
shall not assign the Lease or sublet all or any portion of its Premises Rentable
Area to a Competitor of BGS listed on Exhibit ___ attached hereto, subject,
however, in all respects to the succeeding provisions of this Section___. The
foregoing restriction shall not apply to Tenant subletting all or a portion of
its Premises Rentable Area or assigning this Lease to a Competitor if, pursuant
to the terms of this Lease, Tenant has satisfied all conditions precedent set
forth in this Lease to an assignment of the Lease or a subletting of all or any
portion of the Premises Rentable Area including, without limiting any of the
other provisions set forth in the Lease to Tenant's right to assign this Lease
or sublet the Premises Rentable Area, the obligation to first offer an
assignment of this Lease or the Premises Rentable Area proposed to be sublet by
Tenant to BMC Software, Inc. ("BMC"), an Affiliate of BGS, in the following
fashion. Such right of first offer ("RFO") shall be implemented by Tenant giving
notice (the "RFO Notice") to BMC at the address and in the manner specified
below. A copy of such RFO Notice shall be delivered to Landlord at its notice
address provided in Section ___ of this Lease. The RFO Notice shall specify the
bona fide economic and other principal terms on which Tenant intends to assign
this Lease or sublet all or any portion of the Premises Rentable Area to a
Competitor listed on Exhibit ___ hereto, accompanied by Tenant's written
proposal made to such Competitor. If, not later than midnight of the second
(2nd) Business Day following receipt by BMC of the RFO Notice, Tenant has not
received a written notice from BMC electing to accept Tenant's transaction terms
set forth in the RFO Notice, then the RFO shall be of no further force or effect
and Tenant may undertake to assign the Lease or sublet the Premises Rentable
Area at any time thereafter to such Competitor without again complying with the
RFO provisions herein set forth. If, however, (i) BMC timely elects in writing
to accept the transaction terms set forth in the RFO Notice (the "RFO
Acceptance"),

<PAGE>

                                       -2-

and (ii) within twenty (20) Business Days after receipt by Tenant of the RFO
Acceptance, Tenant and BGS or BMC, as the case may be, fail to execute and
deliver documents in consummation of the terms specified in the RFO Notice for
any reason whatsoever or no reason, then, in such event, the RFO shall be of no
further force and effect and Tenant may undertake to assign this Lease or sublet
the Premises Rentable Area at any time thereafter to such Competitor without
again complying with the RFO provisions herein set forth.

         The foregoing restriction shall not apply (i) if, as noted above, BGS
or its Affiliates are not in actual occupancy of at least 75% of the Premises
Rentable Area in the Complex; (ii) to Affiliates of a Competitor; (iii) to a
Competitor if, after a merger or consolidation by a Competitor with another
entity, or a sale, lease, license or other disposition by a Competitor of all or
substantially all of its assets to another entity, whether in one transaction or
series of transactions, such Competitor is not a surviving entity; or (iv) if,
after a merger or consolidation by BMC with another entity, or a sale, lease,
license or other disposition by BMC of all or substantially all of its assets to
another entity, whether in one transaction or a series of transactions, BMC is
not the surviving entity.

         For so long as the restriction prohibiting Tenant from leasing space in
the Complex to a Competitor listed in Exhibit___ hereto is in force and
applicable, Tenant shall have the right, at any time and from time during the
Lease Term, to request in writing of Landlord and BMC a determination as to
whether the foregoing restriction remains in force and applicable (a
"Restriction Confirmation Request"). Within thirty (30) calendar days after
receipt of Tenant's Restriction Confirmation Request, Landlord or BMC shall
notify Tenant as to whether the restriction set forth in Exhibit___ hereto
remains in force and applicable. Landlord's and BMC's failure to respond to any
Restriction Confirmation Request (if the same shall continue for an additional
thirty (30) calendar days after receipt of a second notice of a Restriction
Confirmation Request, which second notice shall state that Landlord and BMC have
failed to respond within the period required under this Section ___ of the Lease
and continued failure to respond shall be deemed a Landlord confirmation that
such restriction is no longer in force and applicable) shall constitute
Landlord's and BMC's affirmation, acknowledgment and consent that, for the
balance of the Lease Term, the leasing restriction set forth in this
Section___of the Lease shall no longer be applicable.

         An "Affiliate" means (i) any entity directly or indirectly controlling,
controlled by or under common control with such entity; (ii) any entity

<PAGE>

                                       -3-

owning or controlling ten percent (10%) or more of the outstanding voting
interests of such entity; or (iii) any entity of which such entity owns or
controls ten percent (10%) or more of the voting interests.

         Tenant's RFO Notice to BMC shall he in writing and shall be sent by
registered or certified mail, postage prepaid, return receipt requested or by a
nationally recognized overnight courier service (next Business Day delivery) to
BMC at 2101 City West Boulevard, Houston, Texas 77042 Attn: Manager of Corporate
Real Estate (or at such other address or addresses as may from time to time
hereafter he designated by Landlord or BMC by like notice).

         Such notices shall be given, and shall be deemed to have been given and
received, when so hand delivered (against a signed receipt) or three (3) days
after such deposit of such notice by certified or registered mail, or one (1)
day after such deposit of such notice with a nationally recognized overnight
courier; and in the case of failure to deliver by reason of changed address of
which no notice was given or refusal to accept a delivery, such notice shall be
deemed to have been given and received as of the date of such failure as
indicated on the return receipt or by notice of the post office department or
such nationally recognized courier.

<PAGE>

                                    GUARANTY

         FOR VALUE RECEIVED, and in consideration for and as an inducement to
880 Winter Street, L.L.C., a Delaware limited liability company (hereinafter the
"Landlord"), with a mailing address c/o Leggat McCall Properties, L.P., 10 Post
Office Square, Boston, Massachusetts 02109, to enter into, execute and deliver
that certain Lease dated July________________, 1998 (the "Lease") with BGS
Systems, Inc., a Massachusetts corporation (hereinafter the "Tenant"), covering
certain premises within the building numbered 880 Winter Street, Waltham,
Massachusetts, as more particularly described in the Lease, the undersigned, BMC
Software, Inc., a Delaware corporation (hereinafter the "Guarantor"), with a
mailing address at 2101 CityWest Boulevard, Houston, TX 77042, hereby
unconditionally guarantees to the Landlord the prompt payment by Tenant of all
Basic Rent and Additional Charges (as defined in the Lease) under the Lease
within the grace periods therein set forth, if any, and hereby further
guarantees the full and timely performance and observance of all the other
covenants, conditions and agreements therein provided to be performed and
observed by Tenant within the grace periods therein set forth, if any, and the
Guarantor hereby covenants and agrees to and with Landlord that if Tenant, or
its successors or assigns, defaults in the payment of any Basic Rent or
Additional Charges, or if Tenant, its successors or assigns, should default in
the performance and observance of any of the covenants, terms, conditions and
agreements contained in the Lease beyond any applicable grace period therein set
forth, the Guarantor, in each and every instance, shall and will forthwith pay
the Basic Rent and Additional Charges in arrears and shall and will forthwith
faithfully perform and fulfill all of such covenants, terms, conditions and
agreements to which Tenant is in default, and will forthwith pay to Landlord all
damages, including reasonable attorneys' fees, that may arise as a consequence
of any Default of Tenant under the Lease to the extent that the same would be
recoverable against Tenant at law, and all reasonable attorneys' fees and
disbursements incurred by Landlord in the enforcement of this Guaranty.

         This Guaranty is an absolute and unconditional guaranty of payment and
performance and not only collection. It shall be enforceable against Guarantor
without the necessity of any suit or proceedings on Landlord's part of any kind
or nature whatsoever against Tenant or its successors or assigns, and without
the necessity of any notice of non-payment, non-performance or non-observance or
any notice of acceptance of this Guaranty or of any notice or demand to which
Guarantor otherwise might be entitled, all of which Guarantor hereby expressly
waives; and Guarantor expressly agrees that the validity of this Guaranty and
the obligations of Guarantor hereunder shall in no wise be terminated, affected,
diminished or impaired by reason of the granting by Landlord of any indulgences
to Tenant or by reason of the assertion or the failure to assert by Landlord
against Tenant, or against Tenant's successors or assigns, of any of the rights
or remedies reserved to Landlord pursuant to the provisions of the Lease, or by
the relief of Tenant from any of Tenant's obligations under said Lease by
operation of law or otherwise (including, but without limitation, the rejection
of the said Lease in connection with proceedings under the bankruptcy laws now
or hereafter enacted); the Guarantor hereby waiving all suretyship defenses.

         The Guarantor further covenants and agrees that this Guaranty shall be
a continuing guaranty and shall remain and continue in full force and effect as
to any renewal, modification or extension of, or exercise of any expansion
option or right of first offer under said Lease, whether or not the Guarantor
shall have received any notice of or consented to such renewal, modification or
extension or exercise of expansion option or right of first offer. The Guarantor
further agrees that its liability under this Guarantee shall be primary and
that, in any right of action which shall accrue to Landlord under said Lease,
Landlord may, at Landlord's option, proceed against the Guarantor and Tenant,
jointly or severally, and may proceed against the

<PAGE>

                                       -2-

Guarantor without having commenced any action against or having obtained any
judgment against Tenant.

         The Guarantor further represents to Landlord, as an inducement for
Landlord to enter into, execute and deliver said Lease, that the Guarantor owns
all of the entire outstanding capital stock of Tenant, that the execution and
delivery of this Guaranty is not in contravention of its Charter or By-Laws or
applicable Sate laws, and has been duly authorized by its Board of Directors.

         It is agreed that the failure of Landlord to insist in any one or more
instances upon a strict performance or observance of any of the terms,
provisions or covenants of the Lease or to exercise any right therein contained
shall not be construed or deemed to be a waiver or relinquishment for the future
of such term, provision, covenant or right, but the same shall continue and
remain in full force and effect. Receipt by Landlord of Rent or Additional
Charges with knowledge of the breach of any provision of the Lease shall not be
deemed a waiver of such breach.

         No subletting, assignment or other transfer of the Lease, or any
interest therein, shall operate to extinguish or diminish the liability of the
Guarantor under this Guaranty; and, wherever reference is made to the liability
of Tenant named in the within Lease, such reference shall be deemed likewise to
refer to Guarantor.

         The Guarantor covenants to provide Landlord with the notice of any
Security Deposit Event (as defined in the Lease) at the times and in the manner
set forth in Section 14.17 of the Lease and to cause Tenant to provide any
security deposit required in connection with any such Security Deposit Event as
provided in Section 14.17. The Guarantor covenants to deliver, or cause the
Tenant to deliver, to the Landlord its financial statements in the manner and at
the times required by Section 14.23 of the Lease.

         The Guarantor agrees that whenever at any time or from time to time
Guarantor shall make any payment to Landlord or perform or fulfill any covenant,
term, condition or agreement hereunder on account of the liability of Guarantor
under this Guaranty, Guarantor will notify Landlord in writing that such payment
or performance, as the case may be, is for such purpose. No such payment or
performance by Guarantor pursuant to any provision hereof shall entitle
Guarantor by subrogation or otherwise to the rights of Landlord to any payment
by Tenant or to the property of Tenant, except after payment of all sums or
fulfillment of all covenants, terms, conditions or agreements then to be paid or
performed by Tenant or its successors or assigns under the Lease.

         The Guarantor and Landlord agree that each will, at any time, and from
time to time, within ten (10) calendar days following written request by the
other, execute, acknowledge and deliver to the party requesting the same a
statement certifying that this Guaranty is unmodified and in full force and
effect (or if there have been modifications, that the same is in full force and
effect as modified and setting forth such modification), and Landlord shall also
state in such certificate whether, as of the date thereof, Guarantor has paid
and performed such of its obligations thereunder which Guarantor has theretofore
been notified to pay and perform. Guarantor and Landlord agree that such
certificate may be relied upon by anyone holding or proposing to acquire any
interest in the Premises (as defined in the Lease) from or through Landlord or
Tenant, or by any mortgagee or prospective mortgagee of the Premises or of the
land and building of which the Premises are a part.

         Any notice, demand or other communication (herein collectively a
"Notice") given hereunder or in connection herewith shall be in writing and
shall have been deemed to have

<PAGE>

                                       -3-

been properly given, rendered or made, when hand delivered or deposited with a
nationally recognized overnight courier or with the United States Post Office,
by certified mail, return receipt requested, addressed to Landlord or Guarantor,
at the respective addresses for Landlord and Guarantor hereinabove set forth in
this instrument of Guaranty. Either Landlord or Guarantor may, by Notice as
aforesaid, designate a different address or attention designation for Notices
intended for it. Such Notice shall be given, and shall be deemed to have been
given and received, when so hand delivered (against a signed receipt) or three
(3) days after such deposit of such Notice by certified mail enclosed in a
security closed post-paid wrapper, in a United States Post Office, or one (1)
day after such deposit of such Notice with a nationally recognized overnight
courier; and in the case of failure to deliver by reason of changed address of
which no Notice was given or refusal to accept delivery, as of the date of such
failure as indicated on the return receipt or by notice of the post office
department or such nationally recognized courier.

         As a further inducement to Landlord to enter into, execute and deliver
the Lease, and in consideration thereof, Landlord and Guarantor covenant and
agree that in any action or proceeding brought on, under, or by virtue of this
Guaranty, Landlord and Guarantor shall and do hereby waive trial by jury.

         It is further agreed that all of the terms and provisions hereof shall
be binding upon and inure to the benefit of Landlord and Guarantor, and their
respective legal representatives, successors and assigns.

         Initially capitalized words not defined in this Guaranty shall have the
meanings set forth in the Lease.

         This Guaranty shall be governed by, and construed and enforced in
accordance with, the law of the Commonwealth of Massachusetts, as the same may
from time to time exist.

         IN WITNESS WHEREOF, Guarantor has caused this instrument to be executed
in its corporate name by its duly authorized representative, and its corporate
seal to be affixed hereto, this 15th day of July, 1998.

                                   BMC SOFTWARE, INC.

                                   By: /s/ William Austin
                                       --------------------------
                                   Name: William Austin
                                   Title: SVP & CFO
                                   Hereunto duly authorized
                                                                [Corporate Seal]

Attest /s/ Mark D. Taylor
       ----------------------
Name: Mark D. Taylor
      Vice President

<PAGE>

                                       -4-

STATE OF TEXAS          )
                        )   ss.
COUNTY OF HARRIS        )

         On the 15th day of July 1998 before me personally appeared William M.
Austin who, being by me duly sworn, did say that he (she) is S.V.P. & CFO of BMC
Software, Inc., a Delaware corporation, that (he) (she) knows the seal of said
Corporation and that the seal affixed to said instrument is the corporate seal
of said Corporation, and that said instrument was signed and sealed in behalf of
said Corporation by authority of its Board of Directors, and said
_________________ acknowledged said instrument to be the free act and deed of
said Corporation.

                                   Name: Geneva M. Harris

                                   Notary Public in the State of Texas

                                   My commission expires: July 9, 2001

                                   [Notarial Seal]

<PAGE>

                            FIRST AMENDMENT TO LEASE

THIS FIRST AMENDMENT TO LEASE made as of this 31 day of August, 1999, between
880 Winter Street, L.L.C., a Delaware limited liability company ("Landlord"),
having an office c/o Leggat McCall Properties LLC, 10 Post Office Square,
Boston, Massachusetts 02109, and BGS Systems, Inc., a Massachusetts corporation
("Tenant") having an office at One First Avenue, Waltham, Massachusetts 02154.

                                   WITNESSETH:

         1.       Landlord and Tenant heretofore have entered into a written
Lease dated as of July 15, 1998 (hereinafter referred to as the "Lease") for the
leasing by Landlord to Tenant of certain space on the first, second and third
floors in the building known as 880 Winter Street, Waltham, Massachusetts. Terms
not defined herein shall have the meanings assigned therefor in the Lease.

         2.       The Site Plan which is attached as Exhibit B to the Lease
depicts only 880 Winter Street, Waltham, Massachusetts ("880 Winter Street") as
the "Site". For purposes of computing "Operating Expenses" under the Lease, the
definition of "Site" should have also included the adjoining site to 880 Winter
Street owned by an affiliate of Landlord known as 890 Winter Street, Waltham,
Massachusetts ("890 Winter Street"), which adjoining site is shown on Attachment
A hereto.

         3.       For good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Landlord and Tenant desire to
amend the Lease as follows:

         (a)      The references in the Lease to "Site" set forth in the
                  definitions of "Base Operating Expenses", "Common Site
                  Operating Expenses" and "Operating Expenses", in Sections
                  9.1(b), (d) and (f) and in Exhibit E (Operating Expenses)
                  shall be deemed to refer collectively to 880 Winter Street and
                  890 Winter Street. All other references in the Lease to "Site"
                  shall continue to refer to 880 Winter Street only.

         (b)      The references to the "Building" or the "Property" in the
                  exclusions from Operating Expenses in Exhibit E (Operating
                  Expenses) shall be deemed to refer to the "Building and/or the
                  Site".

         4.       Except as expressly amended hereby, all of the terms,
provisions and conditions of the Lease are hereby ratified, confirmed and remain
in full force and effect.

         5.       This First Amendment to Lease may be executed in multiple
counterparts, each of which shall be deemed an original for all purposes.

<PAGE>

         IN WITNESS WHEREOF, Landlord and Tenant have respectively signed and
sealed this First Amendment to Lease as an instrument under seal as of the date
hereinabove set forth.

         LANDLORD:                 880 WINTER STREET, L.L.C.

                                   By: Winter Street OpCo, L.L.C.

                                       By: Leggat McCall Opportunity
                                           Investors, LLC, its managing
                                           member

                                           By: LM Opportunity
                                               Principals LLC, its
                                               managing member

                                               By: /s/ [ILLEGIBLE]
                                                   -----------------------
                                               Name: [ILLEGIBLE]
                                               Title: Authorized Member

         TENANT:                   BGS SYSTEMS, INC.

                                   By: /s/ William M. Austin
                                       -----------------------
                                   Name: WILLIAM M. AUSTIN
                                   Title: SVP & CFO

         Consented and Agreed to:

         GUARANTOR:                BMC SOFTWARE, INC.

                                   By:    /s/ Mark D. Taylor
                                          --------------------
                                   Name:  Mark D. Taylor
                                   Title: Vice President of Operations

<PAGE>

                            SECOND AMENDMENT TO LEASE

         This Second Amendment to Lease (the "Amendment") is entered into as of
the 28th day of September, 2001 by and between Waltham Winter Street 880 LLC
("Landlord") and BGS Systems, Inc. ("Tenant"). This Amendment amends that
certain Lease dated July 15,1998, and the First Amendment thereto dated as of
August 31,1999, between 880 Winter Street, L.L.C., predecessor in interest to
Landlord, and Tenant pursuant to which Tenant currently leases 175,584 rentable
square feet of space on the first, second and third floors (the "Existing
Premises") of the building known and numbered as 880 Winter Street, Waltham,
Massachusetts (the "Building"). Landlord is the successor in interest to all the
right, title and interest of 880 Winter Street, L.L.C., as Landlord, in and to
the Lease. Capitalized terms not defined herein shall have the meaning ascribed
to them in the Lease.

         For good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged by the parties, Landlord and Tenant hereby amend
the Lease as follows:

         1.   On or before December 31,2001, Landlord may notify Tenant that the
              rights of the Tenant pursuant to Section 17.1 of the Lease
              regarding the First Expansion Space shall be deleted from the
              Lease (the "Deletion Notice"). Upon delivery of the Deletion
              Notice, Sections 17.1, 17.2 and 17.3 shall be deemed deleted from
              the Lease, and Tenant shall be entitled to reduce the next
              installment of Basic Rent by $176,000. In the event that Landlord
              does not deliver the Deletion Notice on or before December
              31,2001, Sections 17.1, 17.2 and 17.3 shall remain in full force
              and effect.

         2.   Section 14.12 is hereby amended by deleting the second paragraph
              thereof and substituting the following therefor:

                  "If intended for Landlord, addressed to Waltham Winter Street
                  880 LLC, c/o Clarion Partners LP, One Federal Street, Boston,
                  Massachusetts 02110, with a copy to Robert Tuchmann, Esq.,
                  Hale and Dorr LLP, 60 State Street, Boston, Massachusetts
                  02109 (or to such other address or addresses as may from time
                  to time hereafter be designated by Landlord by like notice),
                  provided that Tenant shall have no liability for, and the
                  notice given to Landlord shall not be defective by reason of,
                  the failure to give such notice to Landlord's counsel."

         3.   Except as herein amended, the Lease including Tenant's rights with
              respect to the second and third expansion spaces shall remain in
              full force and effect.

<PAGE>

         IN WITNESS WHEREOF, this Amendment has been executed as of the day and
year first written above.

                                   LANDLORD:

                                   Waltham Winter Street 880 LLC

                                   By: Waltham Winter Street LLC, member

                                       By: Clarion Partners LLC, member

                                           By: /s/ DOUGLAS J. POWER
                                               -----------------------------
                                               Name: Douglas J. Power
                                               Title: Authorized Signatory

                                   TENANT:

                                   BGS Systems, Inc.

                                   By: /s/ Mark Taylor
                                       ---------------------
                                       Name: Mark Taylor
                                       Title: Vice President

<PAGE>

                                  ATTACHMENT A

                                [PLOT PLAN MAP]

<PAGE>

                                    EXHIBIT C

                         FURNITURE, FIXTURES & EQUIPMENT

I.       FLOOR TWO:

         A.       The second floor office and conference room furniture will
                  remain in total. Every office has a bullet table desk, at
                  least one 2 drawer lateral file, one mobile box/file pedestal,
                  one adjustable computer table, either a credenza shell with
                  file or a powered adjustable corner computer table, wall hung
                  flipper door storage, one guest pull up chair and one s/t desk
                  chair.

         B.       Seven conference rooms will be furnished with tables and
                  chairs. One large conference room #2168 is empty. If a
                  presentation marker board is wall hung it will remain.

         C.       The 36 open plan Steelcase metal workstations will remain with
                  all internal file units and majority of the files abutting the
                  workstations with the exception of the following files that
                  Sublessor will take in the move:

                  -        16 pairs of two drawer lateral files with top

                  -        9 three drawer lateral files

                  -        3 five drawer lateral files with above storage

                  -        7 free-standing bookcases in 2nd fl. resource center,
                           3 free standing bookcases on 1st fl.

         D.       One U-line black ice maker in the West kitchen kitchen is the
                  only coffee bar appliance Sublessor will move on this floor.
                  Vendor equipment such as coffee machines and water filtration
                  systems will be disconnected and removed unless Phase Forward
                  decides to contract with existing vendors and retain service.

II.      FLOOR ONE

         Sublessor will leave the furniture in the following briefing center
         rooms:

         A.       Concord training room. ten tables, 20 tan leather s/t chairs,
         custom wired podium.

         B.       Boston Common room. 72 fabric stacking chairs.

         C.       Beacon Hill sales conference room. Horse shoe conference
         table, 20 tan leather s/t chairs. One custom wired podium.

         D.       Public Garden lunch area. Seven 36" dining tables and 26
                  dining chairs.

                                  Exhibit C-l-

<PAGE>

         The following furniture Sublessor will take for new facility:

         E.       One custom millwork nerve center console to left of reception
                  area.

         F.       One custom millwork reception desk.

         G.       Four Cassina Black leather reception lounge chairs.

         H.       (Two) Three seat tan leather sectionals (mfg. unknown) from
                  open meeting area.

         I.       26 Vecta blue fabric s/t conference chairs from Center of
                  Performance Excellence. 4 Tecknion computer tables and
                  matching pedestals.

         J.       One 3 ton portable Ocean Aire AC unit.

         K.       Lexington Training room Furniture. One custom podium, 29
                  Brayton tan leather s/t conf chairs, 15 Vecta tables.

         L.       All Four ceiling mounted projectors with mounting hardware.

         M.       Two Sub-Zero refrigerators.

         N.       Two 30" diam. Amat aluminum lunch tables, with six matching
                  lunch chairs.

         O.       Six small glass and chrome tear drop end tables.

         P.       The computer room, R&D lab and LAN room infrastructure shall
                  remain. This includes 125KVA UPS, four 20 ton Liebert AC units
                  and the 2.5 ton mini mates in each of the LAN rooms and all
                  applicable monitoring hardware and related software (to the
                  extent owned by Sublessor or any licenses related thereto are
                  transferable without consent by, or payment of a fee to, the
                  owner of such software). Sublessor in removing its property
                  from the Premises, will use reasonable efforts to not damage
                  or make inoperable such equipment.

         Q.       Security system components including control devices, servers
                  and monitors shall remain.

III.     GENERAL

         A.       Sublessor will take all art work and potted plants on floors
                  one and two.

                                  Exhibit C-2-

<PAGE>

                                    EXHIBIT D

                        STANDBY LETTER OF CREDIT EXHIBIT

IRREVOCABLE STANDBY LETTER OF CREDIT NO. SVBSFXXXXXX

DATE:

BENEFICIARY:
BMC SOFTWARE, INC.
2101 CITY WEST BOULEVARD
HOUSTON, TEXAS 77042
ATTN: VICE PRESIDENT OF OPERATIONS

APPLICANT:
PHASE FORWARD INCORPORATED
1440 MAIN STREET
WALTHAM, MA 02451-1623

AMOUNT: US$1,300,000.00 (ONE MILLION THREE HUNDRED THOUSAND AND 00/100 U.S.
DOLLARS)

EXPIRATION DATE: APRIL 30, 2005

LOCATION: AT OUR COUNTERS IN SANTA CLARA, CALIFORNIA

DEAR SIR/MADAM:

WE HEREBY ESTABLISH OUR IRREVOCABLE STANDBY LETTER OF CREDIT NO. SVBSFXXXXXX IN
YOUR FAVOR AVAILABLE BY YOUR DRAFT DRAWN ON US AT SIGHT IN THE FORM OF EXHIBIT
"B" ATTACHED AND ACCOMPANIED BY THE FOLLOWING DOCUMENTS:

1.THE ORIGINAL OF THIS LETTER OF CREDIT AND ALL AMENDMENT(S), IF ANY.

2. A DATED CERTIFICATION FROM THE BENEFICIARY SIGNED BY AN AUTHORIZED OFFICER,
FOLLOWED BY ITS DESIGNATED TITLE, STATING ONE OF THE FOLLOWING (WITHOUT NEED TO
CERTIFY AS TO THE OTHER):

(A)      "PHASE FORWARD INCORPORATED IS IN DEFAULT (AS DEFINED IN THE SUBLEASE)
         UNDER THE SUBLEASE AGREEMENT DATED NOVEMBER 3, 2003 (THE "SUBLEASE"),
         BY AND BETWEEN BMC SOFTWARE, INC. (AS "SUBLESSOR/BENEFICIARY") AND
         PHASE FORWARD INCORPORATED (AS "SUBLESSEE/APPLICANT") BEYOND ANY
         APPLICABLE NOTICE AND CURE

                                      D-l-

<PAGE>

         PERIODS EXPRESSLY SET FORTH IN THE SUBLEASE. THE AMOUNT DRAWN HEREBY
         REPRESENTS FUNDS DUE AND OWING TO SUBLESSOR/BENEFICIARY AS A RESULT OF
         SUCH BREACH."

                                       OR

(B)      "WE HEREBY CERTIFY THAT WE HAVE RECEIVED NOTICE FROM SILICON VALLEY
         BANK THAT LETTER OF CREDIT NO. SVBSFXXXXXX WILL NOT BE RENEWED, OR LESS
         THAN 60 DAYS REMAIN UNTIL THE EXPIRATION DATE AND WE HAVE INFORMATION
         AND BELIEF THAT SUCH A NOTICE WAS SENT BUT NOT RECEIVED."

THE LEASE AGREEMENT MENTIONED ABOVE IS FOR IDENTIFICATION PURPOSES ONLY AND IT
IS NOT INTENDED THAT SAID LEASE AGREEMENT BE INCORPORATED HEREIN OR FORM PART OF
THIS LETTER OF CREDIT.

                                   PAGE 1 OF 2

IRREVOCABLE STANDBY LETTER OF CREDIT NO. SVBSFXXXXXX
DATED

PARTIAL DRAWS ARE ALLOWED. THIS LETTER OF CREDIT MUST ACCOMPANY ANY DRAWINGS
HEREUNDER FOR ENDORSEMENT OF THE DRAWING AMOUNT AND WILL BE RETURNED TO THE
BENEFICIARY UNLESS IT IS FULLY UTILIZED.

DRAFT(S) AND DOCUMENTS MUST INDICATE THE NUMBER AND DATE OF THIS LETTER OF
CREDIT.

THIS LETTER OF CREDIT SHALL BE AUTOMATICALLY EXTENDED FOR AN ADDITIONAL PERIOD
OF ONE YEAR, WITHOUT AMENDMENT, FROM THE PRESENT AND EACH FUTURE EXPIRATION DATE
UNLESS AT LEAST SIXTY (60) DAYS PRIOR TO THE THEN CURRENT EXPIRATION DATE WE
NOTIFY BENEFICIARY BY REGISTERED MAIL/OVERNIGHT COURIER SERVICE AT THE ABOVE
ADDRESS THAT THIS LETTER OF CREDIT WILL NOT BE EXTENDED BEYOND THE CURRENT
EXPIRATION DATE. IN NO EVENT SHALL THIS LETTER OF CREDIT BE AUTOMATICALLY
EXTENDED BEYOND APRIL 30, 2009. UPON REQUEST OF BENEFICIARY WE AGREE TO PROVIDE
TO BENEFICIARY WITHIN TWO BUSINESS DAYS COPIES OF ANY NONRENEWAL NOTICE.

THIS LETTER OF CREDIT MAY ONLY BE TRANSFERRED IN ITS ENTIRETY BY THE ISSUING
BANK UPON OUR RECEIPT OF THE ATTACHED "EXHIBIT A" DULY COMPLETED AND EXECUTED BY
THE BENEFICIARY AND ACCOMPANIED BY THE ORIGINAL LETTER OF CREDIT AND ALL
AMENDMENTS, IF ANY. PAYMENT OF

                                    Exhibit B
                                       to
                                  Exhibit D-2-

<PAGE>

OUR TRANSFER FEE OF W OF 1/4% OF THE TRANSFER AMOUNT (MINIMUM USD250.00) WILL BE
PAID BY THE BENEFICIARY

ALL DEMANDS FOR PAYMENT SHALT. BE MADE BY PRESENTATION OF THE ORIGINAL
APPROPRIATE DOCUMENTS PRIOR TO 10:00 A.M. CALIFORNIA TIME, ON A BUSINESS DAY AT
OUR OFFICE (THE "BANK'S OFFICE") AT: SILICON VALLEY BANK, 3003 TASMAN DRIVE
SANTA CLARA, CA 95054, ATTENTION: STANDBY LETTER OF CREDIT NEGOTIATION SECTION
OR BY FACSIMILE TRANSMISSION AT: (408) 654-6211 OR (408) 496-2418; AND
SIMULTANEOUSLY UNDER TELEPHONE ADVICE TO: (408) 654-7120 OR (408) 654-3052),
ATTENTION: STANDBY LETTER OF CREDIT NEGOTIATION SECTION WITH ORIGINALS TO FOLLOW
BY OVERNIGHT COURIER SERVICE; PROVIDED, HOWEVER, THE BANK WILL DETERMINE HONOR
OR DISHONOR ON THE BASIS OF PRESENTATION BY FACSIMILE ALONE, AND WILL NOT
EXAMINE THE ORIGINALS.

PAYMENT AGAINST CONFORMING PRESENTATIONS HEREUNDER SHALL BE MADE BY BANK DURING
NORMAL BUSINESS HOURS OF THE BANK'S OFFICE WITHIN TWO (2) BUSINESS DAYS AFTER
PRESENTATION.

WE HEREBY AGREE WITH THE DRAWERS, ENDORSERS AND BONAFIDE HOLDERS THAT THE DRAFTS
DRAWN UNDER AND IN ACCORDANCE WITH THE TERMS AND CONDITIONS OF THIS LETTER OF
CREDIT SHALL BE DULY HONORED UPON PRESENTATION TO THE DRAWEE, IF NEGOTIATED ON
OR BEFORE THE EXPIRATION DATE OF THIS CREDIT.

EXCEPT AS OTHERWISE EXPRESSLY STATED HEREIN, THIS LETTER OF CREDIT IS SUBJECT TO
THE INTERNATIONAL STANDBY PRACTICES 1998 ("ISP98"), INTERNATIONAL CHAMBER OF
COMMERCE, PUBLICATION NO. 590.

________________________________        __________________________________
      AUTHORIZED SIGNATURE                     AUTHORIZED SIGNATURE

                                   PAGE 2 OF 2

                                   EXHIBIT "A"

DATE:

TO: SILICON VALLEY BANK
    3003 TASMAN DRIVE                   RE: STANDBY LETTER OF CREDIT
    SANTA CLARA, CA 95054                   NO.            ISSUED BY
    ATTN:INTERNATIONAL DIVISION.            SILICON VALLEY BANK, SANTA CLARA
         STANDBY LETTERS OF CREDIT          L/C AMOUNT:

GENTLEMEN:

                                    Exhibit B
                                       to
                                  Exhibit D-3-

<PAGE>

FOR VALUE RECEIVED, THE UNDERSIGNED BENEFICIARY HEREBY IRREVOCABLY TRANSFERS TO:

(NAME OF TRANSFEREE)
(ADDRESS)

ALL RIGHTS OF THE UNDERSIGNED BENEFICIARY TO DRAW UNDER THE ABOVE LETTER OF
CREDIT UP TO ITS AVAILABLE AMOUNT AS SHOWN ABOVE AS OF THE DATE OF THIS
TRANSFER.

BY THIS TRANSFER, ALL RIGHTS OF THE UNDERSIGNED BENEFICIARY IN SUCH LETTER OF
CREDIT ARE TRANSFERRED TO THE TRANSFEREE. TRANSFEREE SHALL HAVE THE SOLE RIGHTS
AS BENEFICIARY THEREOF, INCLUDING SOLE RIGHTS RELATING TO ANY AMENDMENTS,
WHETHER INCREASES OR EXTENSIONS OR OTHER AMENDMENTS, AND WHETHER NOW EXISTING OR
HEREAFTER MADE. ALL AMENDMENTS ARE TO BE ADVISED DIRECT TO THE TRANSFEREE
WITHOUT NECESSITY OF ANY CONSENT OF OR NOTICE TO THE UNDERSIGNED BENEFICIARY.

THE ORIGINAL OF SUCH LETTER OF CREDIT IS RETURNED HEREWITH, AND WE ASK YOU TO
ENDORSE THE TRANSFER ON THE REVERSE THEREOF, AND FORWARD IT DIRECTLY TO THE
TRANSFEREE WITH YOUR CUSTOMARY NOTICE OF TRANSFER.

SINCERELY,

______________________________
    (BENEFICIARY'S NAME)

______________________________
  SIGNATURE OF BENEFICIARY

SIGNATURE AUTHENTICATED

______________________________
       (NAME OF BANK)

______________________________
    AUTHORIZED SIGNATURE

                                    Exhibit B
                                       to
                                  Exhibit D-4-

<PAGE>

                                   EXHIBIT "B'

  DATE:_______________________                      REF.                     NO.
__________________

  AT SIGHT OF THIS DRAFT

  PAY TO THE ORDER OF______________________

US$___________________________

  USDOLLARS
________________________________________________________________________________

________________________________________________________________________________

_____

  DRAWN UNDER SILICON VALLEY BANK, SANTA CLARA, CALIFORNIA, STANDBY

  LETTER OF CREDIT NUMBER NO. ___________________________________________ DATED
________________________________

  TO: SILICON VALLEY BANK
      3003 TASMAN DRIVE

________________________________
      SANTA CLARA, CA 95054                          (BENEFICIARY'S NAME)
________________________________
                                                         AUTHORIZED SIGNATURE

                         GUIDELINES TO PREPARE THE DRAFT

1.   DATE: ISSUANCE DATE OF DRAFT.

2.   REF. NO.: BENEFICIARY'S REFERENCE NUMBER, IF ANY.

                                    Exhibit B
                                       to
                                  Exhibit D-5-

<PAGE>

3.   PAY TO THE ORDER OF: NAME OF BENEFICIARY AS INDICATED IN THE L/C
     (BENEFICIARY SHALL HAVE NO OBLIGATION TO ENDORSE ON THE REVERSE SIDE).

4.   US$: AMOUNT OF DRAWING IN FIGURES.

5.   USDOLLARS: AMOUNT OF DRAWING IN WORDS.

6.   LETTER OF CREDIT NUMBER: SILICON VALLEY BANK'S STANDBY L/C NUMBER THAT
     PERTAINS TO THE DRAWING.

7.   DATED: ISSUANCE DATE OF THE STANDBY L/C.

8.   BENEFICIARY'S NAME: NAME OF BENEFICIARY AS INDICATED IN THE L/C.

9.   AUTHORIZED SIGNATURE: SIGNED BY AN AUTHORIZED SIGNER OF BENEFICIARY.

IF YOU NEED FURTHER ASSISTANCE IN COMPLETING THIS DRAFT, PLEASE CALL OUR L/C
PAYMENT SECTION AND ASK FOR:

ALICA DA LUZ: 408-654-7120
CESAR AGONCILLO: 408-654-3052

                                    Exhibit B
                                       to
                                  Exhibit D-6-

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