Document:

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                                                                    Exhibit 10.9

                     AMENDMENT NO. 3 TO AGREEMENT OF LEASE
                     -------------------------------------

     THIS AMENDMENT NO. 3 TO AGREEMENT OF LEASE is made as of the 31st day of
January, 2000, by and between BRE/RIVERFRONT LLC, a Delaware limited liability
company ("Landlord") and MAINSPRING COMMUNICATIONS, INC., a Delaware corporation
("Tenant").

                                  WITNESSETH:
                                  -----------

     WHEREAS, Landlord leases to Tenant certain premises in the building known
as and located at One Main Street, Cambridge, Massachusetts (the "Building")
pursuant to the terms of a certain Agreement of Lease, dated as of July 31, 1996
(the "Original Lease"), as amended by that certain Amendment No. 1 to Agreement
of Lease dated September, 1998 ("Amendment No. l") and Amendment No. 2 to
Agreement of Lease dated as of November 30,1998 ("Amendment No. 2") (as amended,
the "Lease"); and

     WHEREAS, the parties hereto desire to further amend the Lease as
     hereinafter provided.

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, it is hereby agreed as follows:

     1.   Expansion Space.
          ---------------

          (a)  Landlord and Tenant hereby confirm and agree that the Demised
Premises under the Lease currently consist of 19,362 rentable square feet of
space located on the seventh (7/th/) floor of the Building (the "Seventh Floor
Space"). Effective on the later to occur of (a) the date that Landlord delivers
"broom clean" and vacant possession of the Expansion Space (as hereinafter
defined) to Tenant or (b) July 1, 2000 (the later of such dates being the
"Expansion Space Commencement Date"), approximately 12,209 rentable square feet
of space on the seventh (7/th/) floor and the entire rentable area (consisting
of approximately 31,571 square feet) of the sixth (6/th/) floor of the Building,
as shown on the plans attached hereto as Exhibit A and made a part hereof (the
"Expansion Space") shall be added to the Demised Premises for a term commencing
on the Expansion Commencement Date and ending on the Termination Date, as
extended in paragraph 2 hereof (subject to Tenant's right to extend said term as
hereinafter provided in this Amendment) and shall become subject to all of the
terms and conditions of the Lease. Except as described below, if Landlord is
unable to deliver possession of the Expansion Space due to a casualty, the
holding over or retention of possession of any tenant, under tenant or occupants
in the Expansion Space or any other reason beyond the reasonable control of
Landlord, (i) Landlord shall not be subject to any liability for the failure to
give possession on said date or dates, (ii) the validity of the Lease shall not
be impaired under such circumstances, and (iii) Tenant waives any right to
rescind the Lease and further waives the right to recover any damages which may
result from Landlord's failure to deliver possession of the Expansion Space or
portion thereof to Tenant on the Expansion Space Commencement Date. In the event
Landlord is unable to deliver possession of the Expansion Space on or by August
1, 2000 due to the holding over or
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retention of possession by any tenant or occupant, Landlord shall promptly
institute and diligently pursue to completion a summary process action against
such tenant or occupant, including, without limitation an action to collect any
rents and holdover rents. In addition, if Landlord has reason to believe that
possession of the Expansion Space will not be delivered in the condition
required hereunder by July 1, 2000, Landlord shall endeavor to give Tenant not
less than fourteen (14) days advance notice (which may be in writing) (i) that
Landlord will not be delivering the Expansion Space on July 1, 2000, and (ii) of
the date on which it expects to deliver the Expansion Space in the condition
required hereunder. In the event that Landlord has not delivered the Expansion
Space in the condition required hereunder by August 1, 2000 due to the holdover
of any existing tenant or occupant of the Expansion Space, Tenant shall receive
a credit of $2,550.52 for each day after August 1, 2000 that Landlord does not
deliver the Expansion Space in the condition required hereunder (the "Rent
Credit"). Landlord represents to Tenant that, in the event the existing tenant
of the Expansion Space, Course Technology, Inc. ("Course"), holds over in the
Expansion Space, Course has agreed to pay Landlord $232,735.75 per month (the
"Holdover Rent"), or one and one-half (1 1/2) times the Yearly Fixed Rent as of
August 1, 2000. Landlord and Tenant agree that the Rent Credit shall not be due
and owing by Landlord unless and until Landlord receives the Holdover Rent due
and payable from Course, and Landlord has applied any amounts collected first to
the Yearly Fixed Rent due and owing to Landlord of $155,157.17 (but not default
interest, late charges and costs of collection). Subject to the foregoing, such
Rent Credit shall be applied commencing on the Expansion Space Commencement
Date. In addition, in the event Landlord has not delivered the Expansion Space
in the condition required hereunder by December 1, 2000, Tenant shall have the
right to terminate this Amendment by delivering written notice to Landlord on or
before December 11, 2000 (but in any case prior to the date that Landlord
delivers the Expansion Space in the condition required hereunder), and upon such
termination, this Amendment No. 3 shall be void and of no further force and
effect.

          (b)  The Expansion Space is leased to Tenant in its present "AS IS"
condition, subject to reasonable wear, tear and damage caused by the use of, and
move from, the Expansion Space by the current tenant. Landlord covenants that
the heating, ventilating and air conditioning, electrical and plumbing systems
serving the Expansion Space and any and all stairwells to and from the Seventh
Floor Space and the Expansion Space will be in good working order as of the
Expansion Space Commencement Date.

          (c)  Effective on the Expansion Space Commencement Date, Articles
1.(12) and (16) of the Lease are hereby amended to read in its entirety as
follows:

          "(12) Rentable Area of the Demised Premises:  63,142 square feet"

          "(16) Termination Date:  The last day of the calendar month in which
                                   the date that is five (5) years from the
                                   Expansion Space Commencement Date occurs."

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     2.   Term.  The Term of the Lease and Termination Date (currently November
          ----
30, 2002) with respect to the leasing of the Demised Premises (the Seventh Floor
Space and the Expansion Space) is hereby extended to the last day of the
calendar month in which the date that is five (5) years from the Expansion Space
Commencement Date occurs, or such earlier date upon which said Term may expire
or be terminated pursuant to any of the conditions of limitation or other
provisions of the Lease or pursuant to law.

     3.   Yearly Fixed Rent. Effective on the Expansion Space Commencement Date,
          -----------------
Article 1.(18) of the Lease is hereby amended to read in its entirety as follows
to reflect the increase in the Yearly Fixed Rent payable under the Lease
attributable to the addition of the Expansion Space:

"(18) Yearly Fixed Rent:             (a) During the Period commencing the
                                         Expansion Space Commencement Date
                                         through August 14, 2001:

                                         At the rate of $2,461,355.43 per annum.

                                         ($25.47 per rentable square foot on
                                         7,069 rentable square feet, $36.00 per
                                         annum on 12,293 rentable square feet,
                                         and $42.00 per annum on 43,780 rentable
                                         square feet.)

                                     (b) During the Period commencing August 15,
                                         --------------------------------------
                                         2001 through November 30, 2002:
                                         ------------------------------

                                         At the rate of $2,535,792.00 per annum.

                                         ($36.00 per rentable square foot on
                                         19,362 rentable square feet and $42.00
                                         per rentable square foot on 43,780
                                         rentable square feet.)

                                     (c) During the Period commencing December
                                         1, 2002 through the Termination Date:

                                         At the rate of $2,651,964.00 per annum.

                                         ($42.00 per rentable square foot on
                                         63,142 rentable square feet.)"

     Notwithstanding the foregoing, so long as Tenant does not default in the
payment and performance of its obligations under the Lease beyond the expiration
of applicable notice and cure periods, if any, prior to the Expansion Space
Commencement Date, Landlord agrees to

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excuse Tenant's obligation to pay a portion of Yearly Fixed Rent in the amount
of $281,727.95 (which sum represents one and one-half (1 1/2) months of Yearly
Fixed Rent attributable to the Expansion Space and one (1) month of Yearly Fixed
Rent attributable to the Seventh Floor Space) for the period commencing on the
Expansion Space Commencement Date until such amount is fully credited. The
preceding sentence shall not excuse, or other affect, any other obligation of
Tenant under the Lease, including, but not limited to, the liability for any and
all additional rent due and payable under the Lease (including, without
limitation, charges for parking, electricity, real estate taxes and operating
expenses).

     4.   Tenant's Proportionate Share of Taxes and Operating Expenses.
          ------------------------------------------------------------

          (a)  Effective as of Expansion Space Commencement Date, Section 6.4 of
the Lease is hereby amended by adding the following subsections (d) and (e)
thereto:

                    "(d)  In addition, Tenant's proportionate share of taxes
               pursuant to Section 6.2 with respect to the Expansion Space shall
               be 13.41% (43,780 square feet divided by 326,470 square feet) of
               the amount of said taxes imposed against the Building and Land
               are in excess of those imposed for the fiscal tax year ending
               June 30, 2000, prorated with respect to any portion of a fiscal
               tax year in which the Term of this Lease ends.

                    (e)   In addition, Tenant's proportionate share of operating
               expenses pursuant to Section 6.3 with respect to the Expansion
               Space shall be 13.60% (43,780 square feet divided by 321,917
               square feet) of the amount of said operating expenses (determined
               in accordance with the provisions of Section 6.3) incurred by
               Landlord in the operation and maintenance of the Building and the
               Land in excess of those incurred by Landlord for the calendar
               year 2000, prorated with respect to any portion of a year in
               which the Term of this Lease ends."

          (b)  Effective on December 1, 2002, (i) the provisions of Amendment
No. 1, Amendment No. 2 and this Amendment No. 3 relating to Sections 6.2, 6.3
and 6.4 shall no longer be effective, so that the provisions of Sections 6.2,
6.3 and 6.4 shall be those set forth in the Original Lease, as hereinafter
amended in this paragraph 4(b), (ii) Section 6.2 (Taxes) of the Lease is hereby
amended to delete the words "June 30, 1997" in the sixth (6th) line of the
paragraph and insert the words "June 30, 2000" in lieu thereof, (iii) Section
6.3 (Operating Expenses) of the Lease is hereby amended to delete the words
"December 31, 1996" in the sixth (6th) line of the paragraph and insert the
words "December 31, 2000" in lieu thereof and (iv) Section 6.4 of the Lease is
hereby amended to read in its entirety as follows:

          "6.4 Tenant's Proportionate Share.  Tenant's proportionate share of
               ----------------------------
     taxes pursuant to Section 6.2 and operating expenses pursuant to Section
     6.3, respectively, shall be 19.34% (63,142 square feet divided by 326,470
     square feet) and 19.61% (63,142 square feet by 321,917 square feet),
     respectively."

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     5.  Landlord's Contribution.  Provided that Tenant shall not then be in
         -----------------------
default under the Lease beyond the expiration of applicable notice and cure
periods at the time a request for reimbursement is made, Landlord shall (subject
to, and in accordance with, the provisions of this paragraph) reimburse Tenant
for its expenses incurred in connection with the design and construction of
improvements made in connection with preparing the Demised Premises for Tenant's
occupancy, including, without limitation, architectural, engineering and
permitting fees ("Tenant's Work"). Landlord's reimbursement to Tenant in
connection with Tenant's Work, however, shall in no event exceed, in the
aggregate, $753,510.00 ("Landlord's Base Contribution"). Tenant may by written
notice delivered to Landlord ("Tenant's Contribution Notice") not later than ten
(10) days prior to the Expansion Space Commencement Date elect to increase
Landlord's Contribution by a sum not to exceed $631,420.00 (such sum designated
in Tenant's Contribution Notice is hereinafter defined as "Landlord's Additional
Contribution"). In the event that Tenant makes the foregoing election in
accordance with the terms hereof, (i) the Yearly Fixed Rent set forth in Article
1(18) commencing on the Expansion Space Commencement Date shall be increased by
an amount per annum equal to the Landlord's Additional Contribution times
$.2666, and (ii) Tenant shall deliver to Landlord, together with Tenant's
Contribution Notice, a Letter of Credit in the amount of Landlord's Additional
Contribution to be held in accordance with Exhibit B. For example, in the event
Landlord's Additional Contribution is $631,420.00, then the Yearly Fixed Rent
shall be increased by $168,336.58 per annum. For purpose of this Amendment,
Landlord's Base Contribution and Landlord's Additional contribution shall be
referred to as "Landlord's Contribution". Landlord and Tenant agree to execute
an agreement confirming the Landlord's Additional Contribution and the increase
in the Yearly Fixed Rent. Tenant shall be entitled to be reimbursed not more
than fifteen percent (15%) of Landlord's Contribution for architectural and
engineering fees, and permit and filing fees in connection with Tenant's Work.

     Effective as of the Expansion Space Commencement Date, Landlord shall
reimburse Tenant for the cost of Tenant's Work by disbursing portions of
Landlord's Contribution to Tenant from time to time, but not more often than
once a month, within thirty (30) days after receipt by Landlord of a request for
such reimbursement executed by Tenant and accompanied by a completed requisition
for payment (in form issued by the American Institute of Architects), certified
and sworn to by Tenant's architect, stating: (i) the percentage of completion
attained with respect to each item of Tenant's Work and the cost incurred by
Tenant with respect to such item, and (ii) that the portion of Tenant's Work
theretofore completed has been completed in a good and workmanlike manner, to
the satisfaction of Tenant's architect, substantially in accordance with
Tenant's approved plans and specifications and substantially in compliance with
all laws, ordinances, orders, regulations and requirements of all public
authorities having jurisdiction over the Demised Premises, together with
evidence of Tenant's payment to contractors, suppliers and vendors in accordance
with such requisition. Provided that Tenant shall not then be in default under
the Lease beyond the expiration of applicable notice and cure periods at the
time a request for reimbursement is made, reimbursements shall be made for work
completed and paid for as certified in Tenant's request and its architect's
requisition, subject to a retention of ten (10%) percent until Tenant's Work
shall have been finally completed. Provided

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that Tenant shall not then be in default under the Lease beyond the expiration
of applicable notice and cure periods at the time a request for reimbursement is
made, within thirty (30) days following the last to occur of: (u) Tenant's
request for payment of the final installment of Landlord's Contribution, (v)
completion of Tenant's Work in accordance with the provisions of the Lease, (w)
the certification of Tenant's architect that the same has been completed in a
good and workmanlike manner, to the satisfaction of Tenant's architect,
substantially in accordance with Tenant's approved plans and specifications and
substantially in compliance with all laws, ordinances, orders, regulations and
requirements of all public authorities having jurisdiction over the Demised
Premises, (x) delivery by Tenant to Landlord of waivers of lien from all
contractors who shall have performed work or furnished services, materials or
supplies in connection with Tenant's Work, (y) delivery by Tenant to Landlord of
"as built" drawings (or marked final working drawings) with respect to Tenant's
Work, and (z) evidence of Tenant's payment to contractor of all amounts
requested for reimbursement by Tenant, the balance of Landlord's Contribution
(but not in excess of the total cost of Tenant's Work) which has not been
previously disbursed shall be disbursed to Tenant. Notwithstanding the
foregoing, Landlord shall have no further obligation to disburse Landlord's
Contribution to Tenant with respect to any request for reimbursement from Tenant
not received within twelve (12) months after the Expansion Space Commencement
Date in accordance with the terms of this paragraph.

     6.   Electricity.  Tenant agrees to pay Landlord monthly an amount
          -----------
reasonably estimated by Landlord to equal Tenant's Allocable Electricity Costs
for the electrical energy that Tenant utilizes for light and power in the
Expansion Space pursuant to Section 7.1 of the Lease.

     7.   Parking.
          -------

          (a)  Effective on the Expansion Space Commencement Date, Article 1.(9)
of the Lease is hereby amended to read in its entirety as follows: "(9) Parking
Spaces: Sixty-three (63)."

          (b)  Effective as of the Expansion Space Commencement Date, the fourth
(4/th/) sentence of Section 27.6 (Parking) shall be deleted in its entirety and
Tenant is no longer entitled to Parking Spaces at the monthly charge of $140.00,
and the monthly charge for all Parking Spaces shall be (i) $180.00 per month per
Parking Space for the two (2) year period commencing on the Expansion Space
Commencement Date, and (ii) thereafter from time to time established by Landlord
or an independent contractor as the then prevailing monthly parking charge for
the Building.

     8.   Assignment and Subletting
          -------------------------

          (a)  Landlord and Tenant agree to amend Section 14.4 of the Lease by
adding the following provision at the end thereof:

          "Except for sums received by Tenant for the sale of Tenant's business
or the sale or rental of Tenant's trade fixtures, leasehold improvements,
equipment, furniture, furnishings or

                                       6
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other personal property, if Tenant receives any sums of money or other
consideration in connection with an assignment of the Lease, Tenant shall pay
sixty percent (60%) of such sums to Landlord within five (5) days of its receipt
thereof. If, in connection with an assignment of the Lease or sublease of all or
any portion of the Demised Premises (other than an assignment or sublease in
connection with a sale of tenant's business), Tenant receives any sums of money
or other consideration in connection with the sale or rental of Tenant's trade
fixtures, leasehold improvements, equipment, furniture, furnishings or other
personal property at the Demised Premises in excess of its fair market sale or
rental value, then Tenant shall pay sixty percent (60%) of such sums to Landlord
within five (5) days of its receipt thereof."

          (b)  Landlord and Tenant agree to amend the initial phrase of Section
14.5(2) of the Lease to read as follows:

               "(2) in the event Tenant proposes to assign or sublet in the
               aggregate (taking into account the proposed sublease and all
               existing subleases then in effect) in excess of fifty percent
               (50%) of the square footage of the Demised Premises,"

          (c)  Landlord and Tenant agree that Landlord's so-called right of
recapture set forth in Section 14.5 shall not apply in connection with an
assignment of the Lease or sublease of any portion of the Demised Premises
permitted under Section 14.3 of the Lease.

     9.   Section 3.3 of the Lease (Option to Extend) is hereby deleted in its
entirety, and is of no further force and effect.

     10.  Tenant acknowledges that Landlord has fulfilled its obligations under
Article 4 of the Lease, which shall be of no further force and effect.

     11.  Right of First Offer.
          --------------------

          (a)  Landlord shall offer (the "Offer") to lease to Tenant any portion
of the rentable area of the fifth (5/th/) and eighth (8/th/) floors of the
Building (the "ROFO Space") when the ROFO Space becomes available for leasing.
For purposes of this Section 11, any ROFO Space shall be deemed to be available
for leasing in the following events: (i) the lease of the current tenant of the
ROFO Space expires and such lease has not been extended or a new lease has not
been entered into between such tenant and Landlord, (ii) the lease of any tenant
of ROFO Space is terminated, (ii) a tenant under a lease which contains a
recapture right notifies Landlord that it desires to assign its lease or sublet
all or a portion of the ROFO Space (and in such event Landlord shall exercise
such recapture right in the event Tenant sends the ROFO Space Notice for such
ROFO Space), or (iv) Landlord has the right to accept an assignment of lease of
ROFO Space or sublet ROFO Space from the current tenant. With respect to
subsection (iv) above, Landlord shall exercise the right to accept such
assignment or sublet in the event Tenant sends the ROFO Space Notice for such
ROFO Space and shall assign or sub-sublease such ROFO

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Space to Tenant. Landlord's Offer shall provide the "Market Fixed Rent for the
ROFO Space" (as hereinafter defined) as reasonably and initially determined by
Landlord, the rentable area of the ROFO Space shown on a floor plan and the
anticipated commencement date of the leasing of the ROFO Space. The date which
Landlord actually delivers possession of the ROFO Space to Tenant in "broom
clean" condition, free of all occupants shall be the "ROFO Commencement Date".

     "Market Fixed Rent for the ROFO Space" shall mean the Yearly Fixed Rent
that a willing tenant would pay, and a willing landlord would accept, to lease
the ROFO Space in its "as is" condition pursuant to the Lease, but subject to
the adjustment in the so-called "base years" for payment of Tenant's
proportionate share of taxes and operating expenses. Notwithstanding anything to
the contrary contained in this paragraph, Landlord shall not be obligated to
make the Offer (or, if Landlord has already made the Offer, then, whether or not
Tenant has accepted the Offer, Landlord shall have the unilateral right, in
Landlord's sole discretion, to revoke the Offer) if, on either the date on which
Landlord is obligated to give Tenant the Offer or anytime thereafter through and
including the ROFO Commencement Date, there exists a default under the Lease
which remains uncured beyond applicable notice and cure periods.

          (b)  Tenant shall have the right to accept the Offer by giving
Landlord written notice of such acceptance (the "ROFO Space Notice") within ten
(10) business days after delivery by Landlord to Tenant of the Offer. Time shall
be of the essence with respect to said ten (10) business day period and delivery
of the ROFO Space Notice by Tenant. In the event Tenant fails to accept the
Offer as provided for herein, then Tenant shall have no further rights pursuant
to this paragraph with respect to the ROFO Space (or portion thereof) specified
in the Offer. If Tenant exercises its right to accept the Offer in accordance
with the provisions of this paragraph, then effective as of the ROFO
Commencement Date, (i) the ROFO Space shall be added to, and automatically
deemed to be a part of, the Lease and the Demised Premises, with an expiration
date of the Termination Date, (ii) the Yearly Fixed Rent payable under the Lease
with respect to the ROFO Space shall be the Market Fixed Rent for ROFO Space,
and (iii) Tenant's Proportionate Share (as defined in Section 6.4 of the Lease)
with respect to the leasing of the ROFO Space shall be equal to the rentable
area of the ROFO Space divided by 326,470 for purposes of calculating Tenant's
proportionate share of taxes pursuant to Section 6.2 of the Lease and 321,917
for purposes of calculating Tenant's proportionate share of operating expenses
pursuant to Section 6.3 of the Lease, but Tenant's so-called "base years"
applicable to the determination of Tenant's Proportionate Share of taxes
pursuant to Section 6.2 and operating expenses pursuant to Section 6.3 for the
ROFO Space only shall be the calendar year (for operating expenses) and fiscal
year (for taxes) that includes the ROFO Commencement Date. Promptly after
delivery of the ROFO Space Notice, Landlord and Tenant agree to execute an
amendment of the Lease reflecting the foregoing. If Landlord has reason to
believe that possession of the ROFO Space will not be delivered in the condition
required hereunder by the date specified in the applicable Offer, Landlord shall
give Tenant fourteen (14) days advance written notice (i) that the Landlord will
not be delivering the ROFO Space by the specified date, and (ii) of the date on
which it expected to deliver the applicable ROFO Space in the condition required
hereunder. In the event Landlord is unable to deliver possession of the ROFO
Space on

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the date specified in the applicable Offer due to the holding over or retention
of possession by any tenant or occupant, Landlord shall promptly institute and
diligently pursue to completion a summary process action against such tenant or
occupant.

         (c)  Except as expressly provided in the next sentence, Landlord shall
deliver the ROFO Space to Tenant, and Tenant shall accept the ROFO Space, in
"broom clean" condition, free of all occupants, but otherwise in its existing
"as is" condition as of the ROFO Commencement Date, and Tenant shall not be
entitled to any credit or allowance or other economic concession from Landlord
for the improvement thereof. Landlord covenants that the heating, ventilating
and air conditioning, electrical and plumbing systems serving the ROFO Space
will be in good working order as of the ROFO Commencement Date. If Landlord, for
any reason beyond Landlord's reasonable control, such as a holdover or casualty,
shall be unable to deliver possession of the ROFO Space on the ROFO Commencement
Date, Landlord shall not be subject to any liability, nor shall the validity of
the Lease or the obligations of Tenant hereunder be thereby affected, except
that the ROFO Commencement Date shall be the date that Landlord delivers
possession of the ROFO Space to Tenant. In the event Landlord has not delivered
the applicable ROFO Space in the condition required hereunder within four (4)
months of the date specified in the applicable Offer as the date for delivery of
the same, Tenant shall have the right to withdraw its ROFO Space Notice and the
ROFO Space Notice shall be void and of no further force and effect.

          (d)  This paragraph and Tenant's rights hereunder shall automatically
terminate and become null, void and of no further force and effect upon the
earlier to occur of (a) one (1) year prior to the Termination Date (unless
Tenant has exercised the Renewal Option prior to such date, in which event two
(2) years prior to the expiration of the Renewal Term), (b) the expiration or
termination of the Lease by Landlord or pursuant to law, (c) the termination or
surrender of Tenant's right to possession of the Demised Premises, (d) the
assignment of the Lease by Tenant (except for assignments and subleases made
pursuant to Section 14.3 of the Lease) or (e) the sublease by Tenant of more
than fifty percent (50%) of the rentable area of the Demised Premises, which
subleases have expiration dates within six (6) months of the Termination Date of
the Lease (except for assignments and subleases made pursuant to Section 14.3 of
the Lease).

          (e)  Notwithstanding anything to the contrary contained in this
paragraph, the rights granted to Tenant hereunder shall be at all times subject
and subordinate to the (i) the options and rights of the current tenants and
occupants (and their successors and assigns) of the ROFO Space as of the date of
this Amendment to extend the term of any existing lease, or enter into a new
lease, of the ROFO Space (or any portion thereof), regardless of whether such
election is made pursuant to an option or right granted under such any lease and
(ii) the options and rights granted to other tenants and occupants of the
Building or the building located at 101 Main Street, Cambridge, Massachusetts
(and their successors and assigns) pursuant to their existing leases as of the
date of this Amendment as specified in Exhibit C attached hereto and made a part
hereof.

                                       9
<PAGE>

     12.  Renewal Option.
          --------------

          (a)  Provided that Tenant is not in default under the Lease beyond the
expiration of applicable notice and cure periods on the date Tenant delivers
Tenant's Renewal Notice (as hereinafter defined) or at any time thereafter
through the commencement date of the Renewal Term (as hereinafter defined),
Tenant shall have an option (the "Renewal Option") to renew the Lease for one
(1) consecutive five (5) year term (the " Renewal Term") at the rent and upon
the other terms set forth below by delivering notice to Landlord ("Tenant's
Renewal Notice") exercising the Renewal Option no later than one (1) year prior
to the Termination Date. Time shall be of the essence with respect to Tenant's
exercise of the Renewal Option and delivery of Tenant's Renewal Notice. In the
event that Tenant shall fail to deliver Tenant's Renewal Notice in accordance
with the provisions hereof, Tenant shall be deemed to have forever waived its
right to exercise the Renewal Option. Tenant shall have no further right to
renew or extend the term of the Lease. Promptly after delivery of the Tenant's
Renewal Notice, Landlord and Tenant shall execute and deliver an instrument
reasonably satisfactory to both parties stating that Tenant has or has not
exercised the Renewal Option.

          (b)  Upon Landlord's receipt of Tenant's Renewal Notice in accordance
with the requirements of this paragraph, the Lease, subject to the provisions of
this paragraph, shall be automatically extended for the Renewal Term with the
same force and effect as if the Renewal Term had been originally included in the
term of the Lease, except that (A) the Yearly Fixed Rent under the Lease shall
be equal to of the Market Fixed Rent (as hereinafter defined) as determined in
this paragraph and (B) Tenant's so-called "base years" applicable to the
determination of Tenant's Proportionate Share of taxes pursuant to Section 6.2
and operating expenses pursuant to Section 6.3 shall be adjusted as follows: the
base years shall be the fiscal year in which the Renewal Term commences for
taxes and calendar year in which the Renewal Term commences for operating
expenses. There shall be no rent concessions or obligation of Landlord to
perform or pay for any work during the Renewal Term.

          (c)  The term "Market Fixed Rent" for the Renewal Term shall mean the
Yearly Fixed Rent that a willing tenant would pay, and a willing landlord would
accept, to lease the Demised Premises in its "as is" condition pursuant to the
Lease, but subject to the adjustment in the so-called "base years" for payment
of Tenant's proportionate share of taxes and operating expenses. Landlord shall
endeavor to notify Tenant of its initial determination of Market Fixed Rent no
later than thirty (30) days after receipt of Tenant's Renewal Notice. Tenant
shall have thirty (30) days after Landlord's delivery of notice to Tenant of its
determination of Market Fixed Rent to deliver notice to Landlord objecting to
Landlord's determination, and, if Tenant fails to deliver such notice within
such thirty (30) day period, Tenant shall be deemed to have accepted Landlord's
determination. If Landlord and Tenant shall otherwise fail to agree upon the
Market Fixed Rent for the Renewal Term within fifteen (15) days after Tenant's
timely notice to Landlord that it objects to Landlord's determination, Landlord
and Tenant each shall give notice to the other setting forth the name and
address of an arbitrator designated by such party within fifteen (15) days
thereafter. If either party shall fail to give notice of such designation within
such fifteen (15) day period, then the arbitrator chosen by the party giving
such notice shall make the determination alone. If two arbitrators shall have
been designated, such two arbitrators shall make their determination of Market
Fixed Rent for the Renewal Term in writing and give notice

                                       10
<PAGE>

thereof to each other and to Landlord and Tenant within twenty (20) days of
their designation. The two arbitrators shall have ten (10) days after the
receipt of notice of each other's determination to confer with each other and to
attempt to reach agreement as to the determination of Market Fixed Rent for the
Renewal Term. If such two arbitrators shall fail to concur, then such two
arbitrators shall immediately designate a third arbitrator. If such two
arbitrators shall fail to agree upon the designation of such third arbitrator
within fifteen (15) days, then either party may apply to the American
Arbitration Association or any successor thereto for the designation of such
arbitrator. The third arbitrator shall conduct such hearings and investigations
as he may deem appropriate and shall, within twenty (20) days after the date of
designation of the third arbitrator, determine the Market Fixed Rent for the
Renewal Term. The determination pursuant to this paragraph cannot exceed the
higher of the determinations made by the arbitrators selected by Landlord and
Tenant and cannot be lower than the lower of the determinations made by the
arbitrators selected by Landlord and Tenant. The determination by the third
arbitrator shall be binding upon Landlord and Tenant. All arbitrators shall be
commercial leasing brokers or appraisers having at least fifteen (15) years
experience in the Cambridge, Massachusetts market. Each party shall pay its own
counsel fees and expenses, if any, in connection with any arbitration under this
paragraph, including the expenses and fees of any arbitrator selected by it in
accordance with the provisions of this paragraph, 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 shall be final and
binding upon Landlord and Tenant. The arbitrators shall not have the power to
add to, modify, or change any of the provisions of this Lease.

          (d)  If for any reason the Market Fixed Rent for the Renewal Term
shall not have been determined prior to the commencement of the Renewal Term,
then until the Market Fixed Rent for the Renewal Term and, accordingly, the
Yearly Fixed Rent shall have been finally determined, the Yearly Fixed Rent
shall be the Market Fixed Rent for the Renewal Term as proposed by Landlord.
Upon such final determination, an appropriate adjustment shall be made
reflecting such final determination, and Landlord or Tenant, as the case may be,
shall pay the other any overpayment or deficiency, as the case may be, from the
commencement of the Renewal Term to the date of such final determination.

          (e)  The Renewal Option shall automatically terminate and become null,
void and of no force and effect upon the earlier to occur of (a) the expiration
or termination of the Lease by Landlord or pursuant to law, (b) the termination
or surrender of Tenant's right to possession of the Demised Premises, (c) the
assignment of this Lease by Tenant (except for assignments and subleases
pursuant to Section 14.3 of the Lease), (d) the sublease by Tenant of more than
fifty percent (50%) of the rentable area of the Demised Premises, which
subleases have expiration dates within six (6) months of the Termination Date of
this Lease (except for assignments and subleases pursuant to Section 14.3 of the
Lease), or (e) the failure of Tenant to timely and properly exercise the Renewal
Option.

     13.  Signage.  Landlord agrees to list Tenant's name on the Building
          -------
directory in the lobby of the Building and any multi-tenanted floor lobby
directory.  The initial listings shall be at

                                       11
<PAGE>

Landlord's sole cost and expense; thereafter, Tenant shall pay a reasonable
charge to Landlord for changes to such directory list. Subject to the terms and
conditions of the Lease, Landlord agrees to inscribe "Mainspring" on the
existing sign monument of the Building and on a sign located at the entrance
doors to the Building, at Tenant's sole cost and expense. The inscription and
sign shall be consistent with the Building standards established by Landlord.
Subject to the approval rights of Landlord under the Lease, Tenant shall also
have the right to install signage with its name and logo on or next to the entry
doors to the Demised Premises. The signage rights (other than in the Building's
lobby directory and any multi-tenanted floor lobby directories) granted under
this paragraph are personal to Mainspring Communications, Inc., shall not
benefit any assignee or subtenant (other than assignees permitted pursuant to
Section 14.3 of the Lease), and shall automatically terminate and become null
and void and of no force or effect upon the earlier to occur of (1) the
expiration or termination of the Lease, (2) the termination of the Tenant's
right to possession of the Demised Premises, (3) the assignment of the Lease by
Tenant (except for assignments and subleases pursuant to Section 14.3 of the
Lease), or (4) the sublease by Tenant of fifty percent (50%) or more of the
rentable area of the Demised Premises, which subleases have expiration dates
within six (6) months of the Termination Date of the Lease (except for
assignments and subleases pursuant to Section 14.3 of the Lease).

     14.  Holding Over.  Any holding over by Tenant after the expiration of the
          ------------
Term of the Lease shall be treated as a month-to-month tenancy terminable upon
thirty (30) days written notice by either party at one and one-half (1 1/2)
times the Yearly Fixed Rent and Additional Rent herein provided thereafter, and
shall otherwise be on the terms and conditions set forth in the Lease, as far as
applicable.

     15.  Ground Floor Space.
          ------------------

          (a)  Landlord shall offer (the "Offer") to lease to Tenant a portion
of the rentable area of the first (1/st/) floor of the Building consisting of
approximately 8,000 rentable square feet (the "Ground Floor Space") when the
Ground Floor Space becomes available for leasing from Landlord. For purposes of
this Section 15, the Ground Floor Space shall be deemed to be available for
leasing in the following events: (i) the lease of the current tenant of the
Ground Floor Space expires and such lease has not been extended or a new lease
has not been entered into between such tenant and Landlord, (ii) the lease of
the tenant of Ground Floor Space is terminated, (iii) the tenant under a lease
of the Ground Floor Space which contains a recapture right notifies Landlord
that it desires to assign its lease or sublet all or a portion of the Ground
Floor Space (and in such event Landlord shall exercise such recapture right in
the event Tenant sends the Ground Floor Space Notice (as hereinafter defined)
for such Ground Floor Space), or (iv) Landlord has the right to accept an
assignment of a lease of Ground Floor Space or sublets Ground Floor Space from
the current tenant. With respect to subsection (iv), Landlord shall exercise the
right to accept such assignment or sublet in the event Tenant sends the Ground
Floor Space Notice (as hereinafter defined) for the Ground Floor Space and shall
assign or sub-sublease such Ground Floor Space to Tenant. Landlord's Offer shall
provide the Yearly Fixed Rent as reasonably determined by Landlord, the rentable
area of the Ground Floor Space shown on a floor plan. The date on which Landlord
actually delivers possession of the Ground Floor

                                       12
<PAGE>

Space in "broom clean" condition, free of all occupants shall be the "Ground
Floor Commencement Date". Notwithstanding anything to the contrary contained in
this paragraph, Landlord shall not be obligated to make the Offer (or, if
Landlord has already made the Offer, then, whether or not Tenant has accepted
the Offer, Landlord shall have the unilateral right, in Landlord's sole
discretion, to revoke the Offer) if, on the date on which Landlord is obligated
to give Tenant the Offer, there exists a default under the Lease which remains
uncured beyond applicable notice and cure periods.

          (b)  Tenant shall have the right to accept the Offer by giving
Landlord written notice of such acceptance (the "Ground Floor Space Notice")
within ten (10) business days after delivery by Landlord to Tenant of the Offer.
Time shall be of the essence with respect to said ten (10) business day period
and delivery of the Ground Floor Space Notice by Tenant. In the event Tenant
fails to accept the Offer as provided for herein, then Tenant shall have no
further rights pursuant to this paragraph with respect to the Ground Floor Space
specified in the Offer. If Tenant exercises its right to accept the Offer in
accordance with the provisions of this paragraph, then effective as of the
Ground Floor Commencement Date, (i) the Ground Floor Space shall be added to,
and automatically deemed to be a part of, the Lease and the Demised Premises,
for a term with an expiration date of sixty (60) days after the Expansion Space
Commencement Date, and (ii) the Yearly Fixed Rent payable under the Lease with
respect to the Ground Floor Space shall be the Yearly Fixed Rent set forth in
the Offer. There shall be no additional rent for taxes and operating expenses,
but Tenant shall be obligated to pay for electricity as reasonably determined by
Landlord. Promptly after delivery of the Ground Floor Space Notice, Landlord and
Tenant agree to execute an amendment of the Lease reflecting the foregoing.

          (c)  If Landlord, for any reason beyond Landlord's reasonable control,
such as a holdover or casualty, shall be unable to deliver possession of the
Ground Floor Space on the anticipated Ground Floor Commencement Date, Landlord
shall not be subject to any liability, nor shall the validity of the Lease or
the obligations of Tenant hereunder be thereby affected, except that the Ground
Floor Commencement Date shall be the date that Landlord delivers possession of
the Ground Floor Space to Tenant. In the event Landlord has not delivered the
Ground Floor Space in the condition required hereunder within two (2) months of
the date specified in the applicable Offer as the date for delivery of the same,
Tenant shall have the right to withdraw its Ground Floor Space Notice and the
Ground Floor Space Notice shall be void and of no further force and effect.

          (d)  Except as expressly provided in the next sentence, Landlord shall
deliver the Ground Floor Space to Tenant, and Tenant shall accept the Ground
Floor Space, in "broom clean" condition, free of all occupants, but otherwise in
its existing "as is" condition as of the Ground Floor Commencement Date, and
Tenant shall not be entitled to any credit or allowance or other economic
concession from Landlord for the improvement thereof, except that Landlord
agrees to carpet and paint the Ground Floor Space using Building standard
materials on or prior to Ground Floor Commencement Date.  Landlord covenants
that the heating, ventilating and air conditioning system serving the Ground
Floor Space will be operational as of the Ground Floor Commencement Date,
provided, however, Landlord makes no covenants, representations or

                                       13
<PAGE>

warranties as to the sufficiency or quality of such heating, ventilating and air
conditioning system. On or prior to the Ground Floor Commencement Date, Tenant
shall have the right, upon reasonable advance notice to Landlord, to inspect the
Ground Floor Space. In the event such inspection reveals the existence of
asbestos or "hazardous substances and materials" (as defined in Section 15.9 of
the Lease), in violation of applicable laws, then, on or prior to the Ground
Floor Commencement Date, Tenant shall have the right to deliver to Landlord the
written report of the consultant or contractor with the results of such
inspection (the "Inspection Report") and written notice withdrawing its
acceptance of the Offer ("Withdrawal Notice"). If Tenant fails to deliver to
Landlord the Inspection Report and Withdrawal Notice, on or prior to the Ground
Floor Commencement Date, then Tenant's acceptance of the Offer shall be
irrevocable. If Landlord, for any reason beyond Landlord's reasonable control,
such as a holdover or casualty, shall be unable to deliver possession of the
Ground Floor Space on the Ground Floor Commencement Date, Landlord shall not be
subject to any liability, nor shall the validity of the Lease or the obligations
of Tenant hereunder be thereby affected, except that the Ground Floor
Commencement Date shall be the date that Landlord delivers possession of the
Ground Floor Space to Tenant.

          (e)  This paragraph and Tenant's rights hereunder shall automatically
terminate and become null, void and of no further force and effect upon the
earlier to occur of (a) the expiration or termination of the Lease by Landlord
or pursuant to law, (b) the termination or surrender of Tenant's right to
possession of the Demised Premises, (c) the assignment of the Lease by Tenant
(except for assignments and subleases pursuant to Section 14.3 of the Lease),
(d) the sublease by Tenant of more than fifty percent (50%) of the rentable area
of the Demised Premises, which subleases have expiration dates within six (6)
months of the Termination Date of the Lease (except for assignments and
subleases pursuant to Section 14.3 of the Lease), or (e) the failure of Tenant
to timely and properly deliver the Ground Floor Space Notice.

     16.  Delivery of Space.  Notwithstanding anything to the contrary in this
          -----------------
Lease, Landlord shall be responsible, at Landlord's sole expense, for delivering
the Expansion Space, the ROFO Space, the Ground Floor Space and the public
portions of the Building in compliance with the laws, ordinances and regulations
applicable to the Expansion Space, the ROFO Space, the Ground Floor Space and
the public portions of the Building existing as of the date of this Amendment,
including, without limitation, the Americans with Disabilities Act.

     17.  Cleaning.  Landlord agrees to provide cleaning services within the
          --------
Demised Premises (including the Expansion Space and the ROFO Space and Ground
Floor Space if added to the Demised Premises in accordance with the terms of
this Amendment) described in Exhibit D attached hereto and made a part hereof.

     18.  Brokers.  Landlord and Tenant each represent and warrant to the other
          -------
party that, except for Insignia/ESG and The Codman Company, Inc. ("Codman"), it
has not, directly or indirectly, dealt, with respect to the leasing of office
space in the Building, with any broker or had its attention called to the
Expansion Space, or other space to lease in the Building, by any broker.
Landlord and Tenant each agree to hold harmless and indemnify the other against
any

                                       14
<PAGE>

claims for a commission by any other broker, person or firm with whom such party
has dealt in connection with the execution and delivery of this Amendment or out
of negotiations between Landlord and Tenant with respect to the leasing of other
space in the Building. Landlord agrees to pay any commission or other
compensation due and payable to Insignia/ESG and Codman (if any) in connection
with the execution and delivery of this Amendment pursuant to their separate
agreement.

     19.  Notices.  The first paragraph of Article 25 of the Lease shall be
          -------
deleted in its entirety and the following inserted in lieu thereof:

          "Except as expressly stated otherwise in this Lease, any notice or
          other communication required or permitted to be given or made by
          either Landlord or Tenant to the other pursuant to this Lease or
          pursuant to any applicable law or requirement of public authority
          shall be in writing and shall be delivered to such other party
          personally, or sent by registered or certified mail (return receipt
          requested) or by a nationally recognized overnight courier, addressed
          to Tenant and to Landlord at the following address:

          If the Landlord:    c/o The Blackstone Group
                              345 Park Avenue
                              New York, New York 10022
                              Attention:  Mr. Gary Sumers

          With copies to:     The Codman Company, Inc.
                              One Main Street
                              Cambridge, Massachusetts 02142
                              Attention: Property Manager

                              and

                              Cohn Birnbaum & Shea, P.C.
                              350 Bedford Street
                              Stamford, Connecticut 60901
                              Attention: Anthony B. Casareale, Esq.

          If to Tenant:       Mainspring Communications, Inc.
                              One Main Street
                              Cambridge, Massachusetts 02142
                              Attention: Director of Operations

          With copies to:     Testa, Hurwitz & Thibeault, LLP
                              125 High Street
                              High Street Tower

                                       15
<PAGE>

                              Boston, Massachusetts 02110
                              Attention: Real Estate Department

          in accordance with this Article. The date of the giving of
          such bill, statement, notice or communication shall be
          deemed to be the date of personal delivery, the next
          business day if sent by overnight courier, or three (3)
          days after the date deposited in the U.S. Mail if sent by
          certified or registered mail. Either party may, by notice
          from time to time to the other party, designate a different
          address (which, however, shall be located in the
          continental United States and shall not be a Post Office
          Box) for notices intended for it. Any notice of change of
          address shall be deemed to have been given when received by
          the party to whom such notice is given. Each party agrees
          that any notice required to be given to it by the other
          under the provisions of this Lease may be given by the
          other's agents or attorneys, as same are set forth above,
          and in such event, such notice shall be deemed to have been
          given by such party."

     20.  Except as expressly provided herein, as used herein, all capitalized
terms shall have the same meaning as set forth in the Lease.

     21.  Except as expressly modified in this Amendment, the provisions of the
Lease are hereby confirmed and ratified and shall continue in full force and
effect.  In the event that the terms and conditions of this Amendment shall
conflict, or are inconsistent, with the terms and conditions of the Lease, the
terms and conditions of this Amendment shall govern and control.

                                       16
<PAGE>

     IN WITNESS WHEREOF, Landlord and Tenant have caused this instrument to be
executed under seal, all as of the day and year first above written.

                         BRE/RIVERFRONT LLC,
                         a Delaware limited liability company

                         By: BRE/RIVERFRONT HOLDINGS LLC,
                             a Delaware limited liability company,
                             Managing Member

                         By: /s/ William Stein
                             ---------------------------------
                             William Stein
                             Vice President

                         MAINSPRING COMMUNICATIONS, INC.

                         By:   /s/ Stephen E. Henkenmeier
                             ----------------------------
                            Name: Stephen E. Henkenmeier
                            Title: Director of Operations

                                       17
<PAGE>

                                   EXHIBIT A
                                   ---------

                         FLOOR PLAN OF EXPANSION SPACE
                         -----------------------------
                                (To be annexed)
                                ---------------

                                      A-1
<PAGE>

                                   EXHIBIT B
                                   ---------

                                LETTER OF CREDIT
                                ----------------

     Upon delivery of Tenant's Contribution Notice, Tenant will deliver to
Landlord a clean, irrevocable and unconditional letter of credit transferable in
whole or in part by Landlord (such letter of credit and any renewal, amendment
and replacement thereof being referred to herein, collectively, as the "Letter
of Credit") issued by a commercial bank (the "Bank"), reasonably acceptable to
Landlord (Landlord hereby approves Silicon Valley Bank), with a correspondent
relationship with a bank with an office in the Greater Boston area or the
Metropolitan New York City area that Landlord can present the Letter of Credit
for payment, which Letter of Credit shall have a term of one year, be for the
account of Landlord, provide for partial drawdowns and be in the amount of
Landlord's Additional Contribution, as security for the faithful performance and
observance by Tenant of the terms, provisions and conditions of this Lease,
including, without limitation, the surrender of possession of the Demised
Premises to Landlord as herein provided. Tenant agrees to cause the Bank to
renew the Letter of Credit, in the same form, or to obtain a Letter of Credit
from another Bank conforming to the provisions of this Section, annually during
the term of this Lease, at least forty-five (45) days prior to the expiration
thereof so that a Letter of Credit issued by the Bank to Landlord shall be in
force and effect at least three (3) years after the Expansion Space Commencement
Date. It is agreed that in the event Tenant defaults beyond applicable notice
and cure periods in respect of any of the terms, conditions, or provisions of
this Lease, including, but not limited to, the payment of the Yearly Fixed Rent
and additional rent and the aforesaid agreement to cause the Bank to renew the
Letter of Credit, Landlord shall have the right to require the Bank to make
payment to Landlord of all or such portion of the Letter of Credit as may be
required for the payment of any Yearly Fixed Rent and additional rent or any
other sum as to which Tenant is in default beyond applicable notice and cure
periods or for any reasonable sum which Landlord may expend or may be required
to expend by reason of Tenant's default in respect of any of the terms,
covenants and conditions of this Lease, including, but not limited to, any
damages or deficiency in the relating of the Demised Premises, whether such
damages or deficiency accrues before or after summary proceedings or other re-
entry by Landlord provided that a duly authorized representative of Landlord
certifies in writing to the Bank that there has been a default beyond applicable
cure periods under the Lease, without thereby waiving any other rights or
remedies of Landlord with respect to such default. If Landlord applies or
retains any part of the proceeds of the Letter of Credit, Tenant, upon demand,
promptly shall deposit with Landlord a substitute Letter of Credit or deposit
with Landlord cash in the amount so applied or retained so that Landlord shall
have the full Security Amount on hand at all times during the term of this Lease
that is required pursuant to the terms of this Article. The Letter of Credit or
any remaining portion of any sum collected by Landlord thereunder from the Bank,
together with any other portion of any other sums then held by Landlord as
security and which sums Landlord is not entitled to apply or retain with respect
to any default beyond applicable notice and cure periods by Tenant hereunder,
shall be returned to Tenant upon the third anniversary of the Expansion Space
Commencement Date.

                                     B-1
<PAGE>

     Provided that Landlord shall not have drawn on the Letter of Credit or any
cash security, Landlord agrees that Tenant shall have the right to reduce the
amount of the Letter of Credit (or cash security held by Landlord in lieu
thereof) by one-third (1/3) after each of the first, second and third
anniversaries of the Expansion Space Commencement Date.

     Landlord agrees that Tenant, at any time during the term, but at least
forty-five (45) days prior to the expiration of the Letter of Credit, may
deposit with Landlord cash in the amount of Landlord's Additional Contribution,
as security hereunder in lieu of the Letter of Credit. Landlord shall have all
of the same rights with respect to such cash security as Landlord has hereunder
with respect to the Letter of Credit and upon delivery of the cash security,
Landlord shall immediately return the Letter of Credit to Tenant.

     In the event of a sale of the Complex or the Building or lease, conveyance
or transfer of the Complex or the Building, Landlord shall have the right to
transfer the security to the vendee, lessee or transferee ("New Landlord"), and
Tenant shall pay any fees charged by the Bank in connection with transferring
the Letter of Credit, and Landlord shall thereupon be released by Tenant from
all liability for the return of such security; and Tenant agrees to look to the
New Landlord solely for the return of said security and it is agreed that the
provisions hereof shall apply to every transfer or assignment made of the
security to a New Landlord. Tenant further covenants that it will not assign or
encumber or attempt to assign or encumber the Letter of Credit or the monies
deposited herein as security, and that neither Landlord nor its successors or
assigns shall be bound by any assignment, encumbrance, attempted assignment or
attempted encumbrance.

                                      B-2
<PAGE>

                                   EXHIBIT C
                                   ---------

5/th/ Floor:
------------

     .    SH&E: Tenant currently leases 9,887 rentable square feet on the floor,
          with an expiration date of August 15, 2001. Tenant currently has the
          right of first offer on any space that comes available on the 5/th/
          floor. The tenant has a right to renew the lease for one (1)
          additional five (5) year period by giving notice to Landlord by June
          15, 2000.

     .    NERA: Tenant currently leases 21,684 rentable square feet on the
          floor, with an expiration date of May 24, 2004. Tenant has a right to
          renew the lease for one (1) additional five (5) year period by giving
          notice to Landlord by May 24, 2003. Tenant has no right of first
          offer.

8/th/ Floor:
-----------

     .    Veritas Software: Tenant currently leases 26,272 rentable square feet
          on the floor, with an expiration date of July 31, 2001. Tenant has a
          right to renew the lease for one (1) additional five (5) year period
          by giving notice to Landlord by October 31, 2000. Tenant has the Right
          of First Offer on any space that comes available on the 8/th/ floor.

     .    Flynn & Clark: Tenant currently leases 6,395 rentable square feet on
          the floor, with an expiration date of August 27, 2002. Tenant has no
          renewal option in the lease. Tenant has no right of first offer.

                                     C-1
<PAGE>

                                   EXHIBIT D
                                   ---------
                               CLEANING SCHEDULE
                               -----------------
                                (See attached)

                                     D-1
<PAGE>

                                   EXHIBIT D
                                   ---------

                            CLEANING SPECIFICATIONS
                            -----------------------

OFFICE AREA:
------------

DAILY - Monday through Friday inclusive, Massachusetts legal holidays excluded.
-----

1.   Empty all waste receptacles and remove trash to designated area, wash
     receptacles as necessary.

2.   Empty and wipe all ashtrays.

3.   Vacuum all rugs and carpets.

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

5.   Wash and clean all bathrooms and 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.   Sweep and dust mop all uncarpeted areas using a dust treated mop.

9.   Hand dust all grillwork within normal reach.

10.  Wash clean the kitchen counter, sink, exterior cabinetry and wet mop floor
     in kitchen.

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 and doors.

                                      D-2
<PAGE>

3.   Dusting of all venetian blinds.

2X PER YEAR - Wash interior and exterior of perimeter windows.
-----------

MAIN LOBBY, ELEVATORS, BUILDING EXTERIOR AND CORRIDORS -
---------------------------------------------------------

CONTINUED
---------

4.   Spot clean any metal work in lobby.

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

6.   Spot clean and polish guard desk.

7.   Vacuum all corridor carpets.

MONTHLY
-------

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

2.  Shampoo carpeting in elevator.

STAIRWELLS
----------

DAILY - Monday through Friday inclusive, Massachusetts legal holidays excluded.
-----

1.  Sweep all stairwells.

                                      D-3<PAGE>

================================================================================
                                                                   Exhibit 10.10

                              AGREEMENT OF LEASE

                                    BETWEEN

                                404 FIFTH LLC,

                                             Landlord

                                      AND

                       MAINSPRING COMMUNICATIONS, INC.,

                                             Tenant

              --------------------------------------------------

                                   Premises:

                               404 Fifth Avenue
                         Entire 7/th/ and 8/th/ Floors
                           New York, New York 10018

              --------------------------------------------------

================================================================================
<PAGE>

                               TABLE OF CONTENTS
                               -----------------

<TABLE>
<CAPTION>
                                                                                                            Page
                                                                                                            ----
<S>                                                                                                         <C>
ARTICLE 1  Premises: Rent................................................................................      5
           --------------
ARTICLE 2  Condition of Premises.........................................................................      7
           ---------------------
ARTICLE 3  Real Estate Tax Escalation....................................................................      9
           --------------------------
ARTICLE 4  Use...........................................................................................     13
           ---
ARTICLE 5  Alterations and Installations.................................................................     14
           -----------------------------
ARTICLE 6  Repairs.......................................................................................     18
           -------
ARTICLE 7  Requirements of Law...........................................................................     19
           -------------------
ARTICLE 8  Insurance, Loss, Reimbursement Liability......................................................     20
           ----------------------------------------
ARTICLE 9  Damage by Fire or Other Cause.................................................................     23
           -----------------------------
ARTICLE 10 Assignment, Mortgaging, Subletting, etc.......................................................     25
           ---------------------------------------
ARTICLE 11 Electricity/Telecommunications................................................................     29
           ------------------------------
ARTICLE 12 Adjacent Excavation -- Shoring................................................................     31
           ------------------------------
ARTICLE 13 Condemnation..................................................................................     31
           ------------
ARTICLE 14 Access to Premises; Changes...................................................................     33
           ---------------------------
ARTICLE 15 Conditions of Limitation......................................................................     34
           ------------------------
ARTICLE 16 Re-Entry by Landlord; Injunction..............................................................     36
           --------------------------------
ARTICLE 17 Damages.......................................................................................     37
           -------
ARTICLE 18 Landlord's Right to Perform Tenant's Obligations..............................................     38
           ------------------------------------------------
ARTICLE 19 Quiet Enjoyment...............................................................................     39
           ---------------
ARTICLE 20 Services and Equipment........................................................................     39
           ----------------------
ARTICLE 21 Hazardous Materials...........................................................................     41
           -------------------
ARTICLE 22 Invalidity of Any Provision...................................................................     42
           ---------------------------
ARTICLE 23 Brokerage.....................................................................................     43
           ---------
ARTICLE 24 Subordination.................................................................................     43
           -------------
ARTICLE 25 Certificate of Tenant.........................................................................     44
           ---------------------
ARTICLE 26 Legal Proceedings; Waiver of Jury Trial; Attorneys' Fees......................................     45
                              -------------------------------------
ARTICLE 27 Surrender of Premises.........................................................................     46
           ---------------------
ARTICLE 28 Rules and Regulations.........................................................................     47
           ---------------------
ARTICLE 29 Consents and Approvals........................................................................     47
           ----------------------
ARTICLE 30 Notices.......................................................................................     48
           -------
ARTICLE 32 Inability to Perform..........................................................................     49
           --------------------
ARTICLE 34 Security......................................................................................     50
           --------
ARTICLE 35 Continuous Operation..........................................................................     51
           --------------------
ARTICLE 36 Non-Liability/Indemnification.................................................................     52
           -----------------------------
ARTICLE 37 Miscellaneous.................................................................................     53
           -------------
</TABLE>

                                      -i-
<PAGE>

     AGREEMENT OF LEASE dated as of January ___, 2000, by and between 404 FIFTH,
LLC, a New York limited liability company, with its office at 498 Seventh
Avenue, New York, New York (hereinafter referred to as "Landlord") and,
MAINSPRING COMMUNICATIONS, INC., a Delaware corporation, with its office at One
Main Street, Cambridge, Massachusetts (hereinafter referred to as "Tenant").

Lease Definitions
-----------------

     In addition to other terms elsewhere defined in this Lease, the following
words and phrases whenever used in this Lease shall have the meanings set forth
in this Reference Page.

     "Alteration" means any and every alteration, addition, construction,
improvement, installation or modification of or to the Premises, the Building or
the Building Equipment (as defined in Article  14.1) and/or any and every
installation in the Premises or the Building (including, without limitation, all
fixtures, paneling, partitions, railings, cabling, wiring and all electrical,
mechanical, plumbing, heating, ventilating and air conditioning installations
affixed or attached to the Premises).

     "Base Tax Year" shall mean the Taxes (as hereinafter defined) for the
twelve-month period commencing January 1, 2000 and ending December 31, 2000.

     "Brokers" shall mean Insignia/ESG, Inc.

     "Building" shall mean the building known as 404 Fifth Avenue, New York, New
York 10018, Block 838, Lot 48.

     "Business Days" as used in this Lease shall include all days except Sundays
and all days observed by the federal, state or local government as legal
holidays as well as all other days recognized as holidays under applicable union
contracts.

     "Business Hours" as used in this Lease shall mean the hours between 8:00
a.m. and 6:00 p.m. on Business Days except that on Saturdays, Business Hours
shall mean the hours between 8:00 a.m. and 1:00 p.m.

     "Commencement Date" shall mean the date Landlord delivers possession of the
entire 7th Floor of the Building to Tenant in "broom clean" condition.

     "Construction Rules and Regulations" shall mean those certain rules and
regulations as issued by the Landlord with respect to the performance of any
Alteration at the Building.

     "Expiration Date" shall mean 11:59 p.m. on the day prior to the ten-year
anniversary of the Commencement Date.
<PAGE>

     "Fixed Annual Rent, Fixed Rent or fixed annual rent" shall be the aggregate
of the 7/th/ Floor Fixed Annual Rent (as hereinafter defined) and the 8/th/
Floor Fixed Annual Rent (as hereinafter defined).

     The 7th Floor fixed annual rent ("7/th/ Floor Fixed Annual Rent") shall be
as follows:

<TABLE>
<CAPTION>
                                                                          Annual      Monthly Rent
                                                                           Rent
----------------------------------------------------------------------------------------------------
<S>                                                                     <C>           <C>
7th Floor Rent Commencement Date through First Anniversary of 7/th/     $396,000.00   $33,000.00
Floor Rent Commencement Date
----------------------------------------------------------------------------------------------------
First Anniversary of 7/th/ Floor Rent Commencement Date through         $407,880.00   $33,990.00
Second Anniversary of 7/th/ Floor Rent Commencement Date
----------------------------------------------------------------------------------------------------
Second Anniversary of 7/th/ Floor Rent Commencement Date through        $420,116.40   $35,009.70
Third Anniversary of 7/th/ Floor Rent Commencement Date
----------------------------------------------------------------------------------------------------
Third Anniversary of 7/th/ Floor Rent Commencement Date through         $432,719.89   $36,059.99
Fourth Anniversary of 7/th/ Floor Rent Commencement Date
----------------------------------------------------------------------------------------------------
Fourth Anniversary of 7/th/ Floor Rent Commencement Date through        $445,701.48   $37,141.79
Fifth Anniversary of 7/th/ Floor Rent Commencement Date
----------------------------------------------------------------------------------------------------
Fifth Anniversary of 7/th/ Floor Rent Commencement Date through         $459,072.52   $38,256.04
Sixth Anniversary of 7/th/ Floor Rent Commencement Date
----------------------------------------------------------------------------------------------------
Sixth Anniversary of 7/th/ Floor Rent Commencement Date through         $472,844.69   $39,403.72
Seventh Anniversary of 7/th/ Floor Rent Commencement Date
----------------------------------------------------------------------------------------------------
Seventh Anniversary of 7/th/ Floor Rent Commencement Date               $487,030.03   $40,585.84
through Eighth Anniversary of 7/th/ Floor Rent Commencement Date
----------------------------------------------------------------------------------------------------
Eighth Anniversary of 7/th/ Floor Rent Commencement Date through        $501,640.93   $41,803.41
Ninth Anniversary of 7/th/ Floor Rent Commencement Date
----------------------------------------------------------------------------------------------------
Ninth Anniversary of 7/th/ Floor Rent Commencement Date through         $516,690.15   $43,057.52
The Expiration Date
----------------------------------------------------------------------------------------------------
</TABLE>

                                      -2-
<PAGE>

     From the date the Landlord delivers possession of the entire 8/th/ floor of
the Building in accordance with the terms of this Lease to Tenant, Tenant shall
pay to Landlord fixed annual rent for the 8/th/ floor ("8/th/ Floor Fixed Annual
Rent") as follows:

<TABLE>
<CAPTION>

                                                                     Annual        Monthly Rent
                                                                      Rent
------------------------------------------------------------------------------------------------
<S>                                                                  <C>           <C>
8/th/ Floor Rent Commencement Date through First Anniversary of      $429,000.00      $35,750.00
8/th/ Floor Rent Commencement Date
------------------------------------------------------------------------------------------------
First Anniversary of 8/th/ Floor Rent Commencement Date through      $441,870.00      $36,822.50
Second Anniversary of 8/th/ Floor Rent Commencement Date
------------------------------------------------------------------------------------------------
Second Anniversary of 8/th/ Floor Rent Commencement Date through     $455,126.10      $37,927.18
Third Anniversary of 8/th/ Floor Rent Commencement Date
------------------------------------------------------------------------------------------------
Third Anniversary of 8/th/ Floor Rent Commencement Date through      $468,779.88      $39,064.99
Fourth Anniversary of 8/th/ Floor Rent Commencement Date
------------------------------------------------------------------------------------------------
Fourth Anniversary of 8/th/ Floor Rent Commencement Date through     $482,843.27      $40,236.94
Fifth Anniversary of 8/th/ Floor Rent Commencement Date
------------------------------------------------------------------------------------------------
Fifth Anniversary of 8/th/ Floor Rent Commencement Date through      $497,328.56      $41,444.05
Sixth Anniversary of 8/th/ Floor Rent Commencement Date
------------------------------------------------------------------------------------------------
Sixth Anniversary of 8/th/ Floor Rent Commencement Date through      $512,248.41      $42,687.37
Seventh Anniversary of 8/th/ Floor Rent Commencement Date
------------------------------------------------------------------------------------------------
Seventh Anniversary of 8/th/ Floor Rent Commencement Date            $527,615.86      $43,967.99
through Eighth Anniversary of 8/th/ Floor Rent Commencement Date
------------------------------------------------------------------------------------------------
Eighth Anniversary of 8/th/ Floor Rent Commencement Date through     $543,444.33      $45,287.03
Ninth Anniversary of 8/th/ Floor Rent Commencement Date
------------------------------------------------------------------------------------------------
Ninth Anniversary of 8/th/ Floor Rent Commencement Date through      $559,747.65      $46,645.64
The Expiration Date
------------------------------------------------------------------------------------------------
</TABLE>

     Provided Tenant is not otherwise in default of the terms and conditions of
this Lease beyond applicable notice and grace periods and provided the execution
date of this Lease occurs on or before January 15, 2000, the 7th Floor Fixed
Annual Rent shall be fully abated for the later of (i) five (5) months after the
Commencement Date or (ii) through June 15, 2000 (the "7/th/ Floor Rent
Commencement Date") (all additional rent as hereinafter defined shall remain due
and payable). In the event that this lease is not executed on or before January
15, 2000, the 7/th/ Floor Fixed Annual Rent shall be fully abated for five (5)
months after the Commencement Date.

     Provided Tenant is not otherwise in default of the terms and conditions of
this lease beyond applicable notice and grace periods, the 8/th/ Floor Fixed
Annual Rent shall be fully abated for the later

                                      -3-
<PAGE>

of (x) five (5) months after Landlord delivers possession to Tenant of the 8/th/
floor, broom clean or (y) through October 31, 2000. However, in the event
Landlord provides Tenant with possession of the 8/th/ floor on or before June 1,
2000, the 8/th/ Floor Fixed Annual Rent shall be fully abated for five (5)
months after Landlord delivers possession to Tenant of the 8/th/ floor ("8/th/
Floor Rent Commencement Date")(all additional rent as hereinafter defined shall
remain due and payable). Notwithstanding anything to the contrary contained
herein, the 8/th/ Floor Fixed Annual Rent shall not be included in Fixed Annual
Rent if, and for so long as Landlord has not provided to Tenant possession of
the 8/th/ floor as provided in this Lease.

     Notwithstanding anything to the contrary contained in this Lease, Tenant
shall pay, a prorated net monthly rental for the period beginning January 1,
2000 through December 31, 2000 for the portion of fixed annual rent that becomes
due for the 7/th/ Floor and 8/th/ Floors of the Premises in the calendar year
2000 divided by twelve (12). For example, if the Commencement Date occurs on or
before December 31, 1999, the portion of the 7/th/ Floor Fixed Annual Rent that
becomes due in the calendar year 2000 is equal to $231,000.00 ($33,000.00 x 7
months) and the portion of the 8/th/ Floor Fixed Annual Rent that comes due in
the calendar year 2000, provided the 8/th/ Floor Rent Commencement Date occurs
on November 1, 2000, is equal to $71,500.00 (35,750.00 x 2 months). Dividing the
sum of 7/th/ Floor Fixed Annual Rent and the 8/th/ Floor Fixed Annual Rent that
becomes due in the calendar year 2000 ($302,500.00) by twelve (12) equals
$25,208.33 (the "Net Monthly Rental").

     "Interest Rate" shall mean a fluctuating rate of interest per annum equal
to the lesser of (a) 2% above the prime commercial lending rate of interest
announced from time to time by The Chase Manhattan Bank, National Association
(or any successor institution, or, if said bank and its successors are no longer
in existence, any other money center commercial bank in the City of New York of
similar size and stature of Chase Manhattan Bank), at its principal office in
New York City, in effect from time to time or (b) the maximum applicable legal
rate of interest, if any.

     "Landlord" means only the owner, or the mortgagee in possession, of the
Land (as hereinafter defined) and Building (or the owner of a lease of the
Building or of the Land and Building), so that in the event of any transfer of
title to said Land and Building or said lease, or in the event of a lease of the
Building, or of the Land and Building, upon notification to Tenant of such
transfer or lease the said transferor Landlord shall be and hereby is entirely
freed and relieved of all future covenants, obligations and liabilities of
Landlord hereunder. It shall be deemed and construed as a covenant running with
the Land without further agreement between the parties or their successors in
interest, or between the parties and the transferee of title to said Land and
Building or said lease, or the said lessee of the Building, or of the Land and
Building, that the transferee or the lessee has assumed and agreed to carry out
any and all such covenants, obligations and liabilities of Landlord hereunder
from and after the date of such transfer.

     "Legal Requirement(s)" shall mean (i) any laws, statutes and ordinances
(including building codes and zoning regulations and ordinances and the
Americans with Disabilities Act of 1990) and the orders, rules, regulations,
directives and requirements of all federal, state, county, city, municipal and
borough departments, bureaus, boards (including the New York Board of Fire
Underwriters), agencies, offices, commissions and other subdivisions thereof, or
of any official thereof, or of any

                                      -4-
<PAGE>

other governmental public or quasi-public authority, whether now or hereafter in
force, which may be applicable to the Land or Building or the Premises or any
part thereof, or the sidewalks, curbs or areas adjacent thereto, (ii) all
requirements, obligations and conditions of all instruments of record on the
date of this Lease, and (iii) all requirements, obligations and conditions
imposed by the carrier of Landlord's insurance policy for the Building.

     "Lien" means any and every lien of any kind whatsoever for the furnishing
(or alleged furnishing) of (or on account of) labor, materials, services,
facilities, or any other things whatsoever.

     "Premises" shall initially mean the entire 7/th/ floor of the Building as
approximately shown hatched on the floor plan annexed hereto as Schedule A and
shall include the entire 8/th/ floor of the Building after Landlord delivers
possession of the entire 8/th/ floor to Tenant in accordance with the terms of
the Lease (which space is hereinafter referred to as the "Premises").

     "Permitted Use" shall mean executive and general offices, including uses
which are ancillary and customary for executive and general offices (i.e., a
multimedia projection room, employee kitchen and computer room) and for no other
purpose whatsoever.

     "Security Deposit" shall have the meaning set forth in Article 34 this
Lease.

     "Tenant's Proportionate Share" shall mean .25 or (25.00%).

     "Term" shall mean ten (10) years from the Rent Commencement Date of the
entire 7/th/ floor.

                                 W I T N E S S E T H:
                                 - - - - - - - - - -

     The parties hereto, for themselves, their heirs, distributees, executors,
administrators, legal representatives, trustees, successors and assigns, hereby
covenant as follows:

                                   ARTICLE 1

                                 Premises: Rent
                                 --------------

     1.1  Landlord hereby leases to Tenant, and Tenant hereby hires from
Landlord, the Premises for the Term to commence on the Commencement Date and to
end at 11:59 p.m. on the Expiration Date or until such term shall sooner cease
and terminate as hereinafter provided.  In the event that Landlord fails to
deliver possession of the 8/th/ floor in accordance with this Lease by June 1,
2000, Landlord shall commence a holdover proceeding against the tenant occupying
the 8/th/ floor and shall diligently prosecute such holdover proceeding through
completion and Tenant shall have the right to deduct any amount prepaid to
Landlord in connection with the 8/th/ Floor of the Premises from the next
monthly installment payment of fixed annual rent. In the event Landlord is
unable to

                                      -5-
<PAGE>

deliver possession of the 8/th/ floor to Tenant by December 31, 2000, Tenant may
cancel this Lease by providing Landlord with a written fifteen (15) day notice
of termination ("Notice of Termination") in accordance with Article 30 of this
Lease on or before January 15, 2001, time being of the essence, and if Tenant
provides Landlord with such Notice of Termination, this Lease shall terminate
and come to end and neither party shall have any further liability to each
either for any obligation under this Lease.

     1.2  (a)  Except as otherwise provided in the definition of "Fixed Annual
Rent," from and after the 7/th/ Floor and 8/th/ Floor Rent Commencement Date,
Tenant shall pay to Landlord the fixed annual rent at the fixed annual rental
rate set forth in the Reference Pages, which shall be payable in equal monthly
installments on or in advance of the first day of each and every calendar month
during the Term of this Lease. The first monthly installment of the 7/th/ Floor
Fixed Annual Rent shall be payable by Tenant upon the execution of this Lease.
Should the 7/th/ Floor or 8/th/ Floor Rent Commencement Date fall on any day
other than the first day of a month, the 7/th/ Floor or 8/th/ Floor Fixed Annual
Rent for such month shall be pro-rated on a per diem basis, and Tenant shall pay
the amount for such partial month on the 7/th/ Floor or 8/th/ Floor Rent
Commencement Date, as the case may be. Should the Expiration Date fall on any
day other than the last day of a month, then the Expiration Date shall be deemed
modified such that it is the last day of the calendar month in which the
Expiration Date was scheduled to occur and the 7/th/ Floor or 8/th/ Floor Fixed
Annual Rent, as the case may be, for such partial period shall be pro-rated on a
per diem basis. In such event the amount paid by Tenant upon execution of this
Lease shall be applied to the fixed annual rent payable on the first day of the
first month following the Commencement Date.

         (b) Any sum other than fixed annual rent payable hereunder (hereinafter
called "additional rent") shall be deemed additional rent, and together with
fixed annual rent shall be included in the term "rent" and shall, unless
otherwise stated, be due thirty (30) days after demand. Fixed annual rent and
additional rent shall be paid in lawful money of the United States by good and
sufficient check (subject to collection) drawn to Landlord's order or as
Landlord may direct on a bank which is a member of the New York Clearinghouse
Association or a successor thereto. Said checks shall be sent to Landlord at its
address as hereinabove set forth, or to such other party or parties and/or at
such other address(es) as Landlord shall designate by written notice to Tenant.
Tenant, provided it gives Landlord written notice, may also pay rent by wire
transfer to a bank designated by Landlord in writing.

         (c) Tenant shall pay the fixed annual rent and additional rent promptly
when due without notice or demand therefor and without offset, credit,
abatement, deduction, counterclaim or set off or for any reason whatsoever,
except such deduction as may be expressly set forth in Articles 9 and 13.

     1.3  If Tenant shall fail to pay any installment of fixed annual rent or
any payment of additional rent for a period of ten days after such installment
or payment shall have become due, Tenant shall pay interest thereon at the
Interest Rate, from the date when such installment or payment

                                      -6-
<PAGE>

shall have become due to the date of the payment thereof, and such interest
shall be deemed additional rent.

     1.4  If any of the fixed annual rent or additional rent payable under the
terms and provisions of this Lease shall be or become uncollectible, reduced or
required to be refunded because of any Legal Requirements, Tenant shall enter
into such agreement(s) and take such other steps as Landlord may request and as
legally may be permissible to permit Landlord to collect the maximum rents that,
from time to time during the continuance of such legal rent restriction, legally
may be permissible (and not in excess of the amounts reserved therefor under
this Lease). Upon the termination of such legal rent restriction, (a) the rents
shall become and thereafter shall be payable in accordance with the amounts
reserved herein for the periods following such termination and (b) Tenant shall
pay to Landlord, to the maximum extent legally permissible, an amount equal to
(i) the rents that would have been paid pursuant to this Lease but for such
legal rent restriction less (ii) the rents paid by Tenant during the period such
legal rent restriction was in effect.

     1.5  No payment by Tenant or receipt or acceptance by Landlord of a lesser
amount than the correct fixed annual rent or additional rent shall be deemed to
be other than a payment on account, nor shall any endorsement or statement on
any check or any letter accompanying any check or payment be deemed an accord
and satisfaction, and Landlord may accept such check or payment without
prejudice to Landlord's right to recover the balance or pursue any other remedy
provided in this Lease or at law.

     1.6  Landlord shall have the same rights and remedies (including, without
limitation, the right to commence a summary proceeding) for a default in the
payment of additional rent as in a default in the payment of fixed annual rent
notwithstanding the fact that Tenant may not then also be in default in the
payment of fixed annual rent.

     1.7  The exterior walls of the Building, elevators and elevator shafts, and
other Building shafts, electrical closets and conduits which extend to any floor
above or below the Premises, the roof, and the portions of any window sills
outside the windows, and the windows are not part of the Premises and Landlord
reserves all rights to such parts of the Building.

                                   ARTICLE 2

                             Condition of Premises
                             ---------------------

     2.1  Tenant is fully familiar with the condition of the Premises and hereby
accepts possession of the Premises in its current "as is" condition except as
otherwise provided herein.

     2.2  Tenant acknowledges that the bathrooms in the Premises will be
delivered to Tenant in their current "as-is" condition.  In consideration of the
Tenant accepting possession of the bathrooms in the Premises in their current
"as is" condition, provided Tenant is not otherwise in default of any of the
terms and conditions of this Lease beyond applicable notice and grace periods,

                                      -7-
<PAGE>

Tenant shall receive, a one time, Ten Thousand Dollar ($10,000.00) rental
credit, provided such renovation is completed in accordance with all the terms
of this Lease, including, but not limited to, applicable laws and codes and the
American Disabilities Act of 1990.  Tenant shall have the option of applying
such rent credit to any payment of the Fixed Rent or additional rent.

     2.3  Except as otherwise provided in this Article, Landlord shall not be
required to perform, any work or installations which would: (a) require changes
to structural components of the Building or the exterior design of the Building;
(b) require any modification to the Building's Systems or installations outside
the Premises; (c) not comply with all applicable Laws of any Government Entity
having jurisdiction over the construction of the Building and/or the Premises;
and/or (d) be incompatible with plans previously filed for the Building with the
Department of Buildings of the City of New York or with the occupancy of the
Building.  Landlord shall perform the following work or provide Tenant with the
following information for the Premises and the Building:

          (i) As more fully set forth in Article 12 herein, prior to the
Commencement Date, Landlord shall provide electrical power to Tenant for the
Premises through the presently existing electrical facilities for Tenant's
reasonable use of its lighting, and other electrical fixtures, appliances and
equipment;

          (ii) On or prior to the Commencement Date, Landlord shall deliver the
windows contained within the Premises watertight, cleaned and in good working
order;

          (iii)  On or prior to the Commencement Date, Landlord shall deliver
the heating, ventilating and air-conditioning ("HVAC") equipment servicing the
Premises in good working order. The air-conditioning equipment servicing the
7/th/ Floor of the Premises is a self contained "air-cooled" system and the air-
conditioning equipment servicing the 8/th/ Floor of the Premises is a "water-
cooled" system. The water necessary to operate the air-conditioning equipment
servicing the 8/th/ Floor of the Premises is generated exclusively from a water
tower on the roof of the Building. Tenant, at its sole cost and expense, shall
install a water meter to measure the Tenant's consumption of water from such
water tower and Tenant shall be responsible for paying, as additional rent, for
all water consumed by Tenant from such water tower. Provided Tenant, at its sole
cost and expense during the first three years of the Term maintains a
maintenance contract for the air-conditioning equipment, Landlord shall be
responsible for the cost of repairing, and if necessary replacing, the air-
conditioning equipment. After the third anniversary of the Commencement Date,
Tenant shall be solely responsible for all maintenance, repair and replacement
costs of the air-conditioning equipment through the Expiration Date. Landlord
makes no representations or warranties as to the sufficiency of the air-
conditioning equipment for the Tenant's intended use in the Premises. Landlord
represents that the air-conditioning equipment servicing the Premises is
controlled by Tenant. Landlord shall cooperate with Tenant, in providing Tenant
access to the roof of the Building for the Tenant to maintain, repair, and if
necessary, replace the water tower or any air-conditioning equipment related to
the water tower.

                                      -8-
<PAGE>

          (iv) Prior to the Commencement Date, Landlord shall provide Tenant
with an ACP-5 Certificate representing that there is no friable asbestos
contained within the 7th Floor of the Premises and prior to providing Tenant
with possession of the 8th Floor of the Premises, Landlord shall provide Tenant
with an ACP-5 Certificate representing that there is no friable asbestos
contained within the 8th Floor of the Premises;

          (v) Landlord shall deliver the Premises to Tenant in compliance with
all municipal codes, including, the New York Building and Fire Department
Regulations.  In addition, Landlord shall provide Tenant with a commercially
reasonable number of hook-up points to the Building's Class E fire system taking
into consideration the size of the floor plate.  Tenant, at its sole cost and
expense, shall be responsible for hooking up such Class E fire system to the
Premises;

          (vi) On or before July 1, 2000, Landlord shall complete the renovation
and enlargement of the Building's lobby as well as the cosmetic renovation of
two (2) passenger elevator cabs substantially in accordance with the "rendering"
of the Building's lobby attached to this Lease as Schedule B.  The parties
acknowledge that such rendering is annexed hereto for informational purposes
only, is not drawn to scale and does not contain any specifications or formal
plans for the lobby renovation.  If Landlord shall fail to complete such
renovation and enlargement of the Building's lobby as well as the cosmetic
renovation of two (2) passenger elevator cabs by July 1, 2000 and, provided
Tenant is not otherwise in default of any of the terms or conditions of this
Lease beyond applicable notice and grace periods, Landlord shall grant Tenant a
$3,000.00 per month rent credit until such time as Landlord's architect
certifies that such work is complete.  If Landlord shall fail to complete such
renovation and enlargement of the Building's lobby, as well as the cosmetic
renovation of two (2) passenger elevator cabs by December 31, 2000 and, provided
Tenant is not otherwise in default of any of the terms or conditions of this
Lease beyond applicable notice and grace periods, the monthly rent credit
Landlord shall grant to Tenant shall be increased to $10,000.00 per month until
such time as Landlord's architect certifies that such work is complete.

     2.4  All work performed by Tenant in accordance with the provisions of this
Lease shall require the installation of new materials at least comparable to the
quality installed in the Building, shall be performed in accordance with the
terms and conditions of this Lease and the Construction Rules and Regulations.

                                   ARTICLE 3

                          Real Estate Tax Escalation
                           ---------------------------

     3.1  For the purposes of this Article 3, the following definitions shall
apply:

         (a) The term "Base Tax" shall mean the Taxes payable for the Base Tax
Year set forth in the Reference Page. If the Base Tax subsequently shall be
adjusted, corrected or reduced whether as the result of protest, by means of
agreement or as the result of legal proceedings, the Base Tax for the purpose of
computing any additional rent payable pursuant to this Article shall be the

                                      -9-
<PAGE>

Base Tax as so adjusted, corrected or reduced. Until the Base Tax is so
adjusted, corrected or reduced, if ever, Tenant shall pay additional rent
hereunder based upon the unadjusted, uncorrected or unreduced Base Tax and upon
such adjustment, correction or reduction occurring, any additional rent payable
by Tenant prior to the date of such occurrence shall be recomputed and Tenant
shall pay to Landlord any additional rent found due by such recomputation within
ten days after being billed therefor (which bill shall set forth in reasonable
detail the pertinent data causing and comprising such recomputation). Landlord
represents that, Landlord is not receiving nor has Landlord applied for any form
of tax abatement that affects the Base Tax Year.

         (b) The term "Taxes" shall mean all real estate taxes, assessments,
sewer and water rents, governmental levies, municipal taxes, county taxes,
utility taxes or any other governmental charge, general or special, ordinary or
extraordinary, unforeseen as well as foreseen, of any kind or nature whatsoever,
that are or may be assessed, levied or imposed upon all or any part of the land
(hereinafter referred to as the "Land") on which the Building is situated, the
Building and the sidewalks, vault, arcades, plazas, alleys or streets in front
of or adjacent thereto, including any tax, excise or fee payable as a result of
the Building being situated in a business improvement district, including any
tax, excise or fee measured by or payable with respect to any rent or mortgage
and levied against Landlord and/or the Land and/or the Building, and/or against
the holder of any mortgage affecting the Land or the Building, under the laws of
the United States, the State of New York, or any political subdivision thereof,
or by the City of New York, or any political subdivision thereof but excluding
any income, franchise, corporate, estate, inheritance, succession, capital
stock, transfer or mortgage recording tax levied on Landlord or the holder of
any such mortgage). If, due to a future change in the method of taxation or in
the taxing authority, a new or additional real estate tax, or a franchise,
income, transit, profit or other tax or governmental imposition, however
designated, shall be levied against Landlord, and/or the Land and/or the
Building, and/or the sidewalks, arcades, plazas, alleys or streets in front of
or adjacent thereto, in addition to, or in substitution in whole or in part for
any tax which would constitute "Taxes," or in lieu of additional Taxes, such tax
or imposition shall be deemed for the purposes hereof to be included within the
term "Taxes."

         (c) The term "Tax Year" shall mean each period of twelve months,
commencing on the first day of July of each such period, in which occurs any
part of the  Term of this Lease or such other period of twelve months occurring
during the  Term of this Lease as hereafter may be duly adopted as the fiscal
year for real estate tax purposes of the City of New York.

         (d) The term "Escalation Statement" shall mean a statement setting
forth the amount payable by Tenant for a specified Tax Year pursuant to this
Article 3.

     3.2  (a)  Commencing on January 1, 2001, Tenant shall pay as additional
rent for each Tax Year a sum (hereinafter referred to as "Tenant's Tax Payment")
equal to Tenant's Proportionate Share of the amount by which the Taxes for such
Tax Year exceed the Base Tax. Tenant's Tax Payment for each Tax Year shall be
due and payable in advance in monthly installments on the first day of each
month during each Tax Year, based upon the Escalation Statement furnished prior
to the

                                      -10-
<PAGE>

commencement of such Tax Year, until such time as a new Escalation Statement for
a subsequent Tax Year shall become effective. If an Escalation Statement is
furnished to Tenant after the commencement of the Tax Year in respect of which
such Escalation Statement is rendered, Tenant shall, within fifteen (15) days
thereafter, pay to Landlord an amount equal to the amount of any underpayment of
Tenant's Tax Payment with respect to such Tax Year and, in the event of an
overpayment, Landlord shall permit Tenant to credit against subsequent payments
under this Section 3.2(a) or against next Fixed Rent payments in the amount of
Tenant's overpayment. If there shall be any increase in Taxes for any Tax Year,
whether during or after such Tax Year, Landlord shall furnish a revised
Escalation Statement for such Tax Year, and Tenant's Tax Payment for such Tax
Year shall be adjusted and paid substantially in the same manner as provided in
the preceding sentence. If during the Term of this Lease, Taxes are required to
be paid (either to the appropriate taxing authorities or as tax escrow payments
to a superior mortgagee) in full or in monthly, quarterly, semiannually or other
installments, on any other date or dates than as presently required, then at
Landlord's option, Tenant's Tax Payments shall be correspondingly accelerated or
revised so that said Tenant's Tax Payments are due at least twenty (20) days
prior to the date payments are due to the taxing authorities or the superior
mortgagee. The benefit of any discount for any early payment or prepayment of
Taxes shall accrue solely to the benefit of Landlord and such discount shall not
be subtracted from Taxes. Landlord shall provide Tenant with a copy of the tax
invoices which the Tenant's Tax Payment is based upon.

         (b) If the real estate tax fiscal year of The City of New York shall be
changed during the  Term of this Lease, any Taxes for such fiscal year, a part
of which is included within a particular Tax Year and a part of which is not so
included, shall be apportioned on the basis of the number of days in such fiscal
year included in the particular Tax Year for the purpose of making the
computations under this Section 3.2(a).

         (c) If the Taxes for any Tax Year for which Tenant shall have paid
additional rent pursuant to this Article shall be adjusted, corrected or reduced
whether as the result of protest of any tentative assessment, or by means of
agreement, or as the result of legal proceedings, the additional rent becoming
due in said Tax Year pursuant to this Article shall be determined on the basis
of said corrected, adjusted or reduced Taxes. If Tenant shall have paid any
additional rent pursuant to this Article for such Tax Year prior to any said
adjustment, Landlord shall credit against the next Fixed Rent payment or refund
to Tenant any excess amount thus paid as reflected by said adjusted Taxes, less
Tenant's Proportionate Share of any reasonable cost, expense or fees directly
related to the successful reduction of Taxes (including reasonable experts' and
reasonable attorneys' fees and Landlord's reasonable costs of administration and
coordination) incurred by Landlord in obtaining said tax adjustment. If said tax
adjustment shall occur prior to Tenant's payment of any said Taxes due hereunder
as additional rent, Tenant shall pay, as additional rent, Tenant's Proportionate
Share of any reasonable cost, expenses or fees (including reasonable experts'
and reasonable attorneys' fees and Landlord's costs of administration and
coordination) incurred by Landlord in obtaining said tax adjustment.

                                      -11-
<PAGE>

     3.3  In the event that the Commencement Date shall be other than the first
day of a Tax Year or the date of the expiration or other termination of this
Lease shall be a day other than the last day of a Tax Year, then, in applying
the provisions of this Article 3 with respect to any Tax Year in which such
event shall have occurred, appropriate adjustments shall be made to reflect the
occurrence of such event on the basis of the portion of such Tax Year that shall
have elapsed after the  Term hereof commences in the case of the Commencement
Date, and prior to the date of such expiration or termination in the case of the
Expiration Date or other termination.

     3.4  In no event shall the fixed annual rent be reduced by operation of
this Article 3. The rights and obligations of Landlord and Tenant under the
provisions of this Article 3 with respect to any additional rent shall survive
the expiration or other termination of this Lease.

     3.5  Landlord's failure to render an Escalation Statement with respect to
any Tax Year shall not prejudice Landlord's right thereafter to render an
Escalation Statement with respect thereto or with respect to any subsequent Tax
Year unless Landlord has failed to render an Escalation Statement with respect
to any Tax Year within fifteen (15) months of such Tax Year. Payments shall be
made pursuant to this Article 3 notwithstanding the fact that an Escalation
Statement is furnished to Tenant after the expiration of the  Term of this
Lease.

     3.6  Each Escalation Statement shall be conclusive and binding upon Tenant
unless within sixty (60) days after receipt of such Escalation Statement Tenant
shall notify Landlord that it disputes the correctness of such Escalation
Statement, specifying the particular respects in which such Escalation Statement
is claimed to be incorrect. Pending the determination of such dispute, Tenant
shall pay additional rent in accordance with the Escalation Statement that
Tenant is disputing, without prejudice to Tenant's position.

     3.7  In the event of a dispute between the parties as to whether an
Escalation Statement is correct in accordance with Section 3.6, Tenant (the
"Initiating Party") may apply to the President of the Real Estate Board of the
City of New York (the "Real Estate Board") for the designation of an arbitrator
to determine that question.  The Initiating Party shall submit a copy of such
application to the other party.  In the event that the President of the Real
Estate Board has not designated an arbitrator within ten (10) days after the
date of the application, the Initiating Party may apply to a Court of competent
jurisdiction to designate an arbitrator.  The arbitrator appointed pursuant to
this Section 3.7 shall be a real estate consultant with at least ten (10) years
experience in the New York City commercial real estate market.  The parties
shall execute all documents and do all other things necessary to submit the
issue to arbitration pursuant to this Section 3.7.  The hearing held by the
arbitrator shall take place in the Borough of Manhattan at such location and
time as shall be specified by the arbitrator.  Each of the parties shall be
entitled to be present at the hearing and to present all relevant evidence.  The
arbitration shall hold the hearing and render his decision within fourteen (14)
days after the date of his designation.  The parties shall take all reasonable
measures to facilitate the arbitration and to permit the arbitrator to render
his decision within the said fourteen (14) day period.  The decision shall be in
writing and copies thereof shall be submitted to both parties.  The sole
decision to be made by the arbitrator shall be whether the Escalation Statement
in question is correct

                                      -12-
<PAGE>

as described in Section 3.6. If the decision is in the negative, the award shall
be in favor of Tenant, and if the decision is in the affirmative, the award
shall be in favor of Landlord. The arbitrator shall have no power to award any
damages to either party or to vary, modify or waive any provision of this Lease.
The decision of the arbitrator shall be final and binding upon the parties. In
any arbitration proceeding instituted in accordance with this Section 3.7, the
parties shall pay for their own attorneys' fees and consultant's fees and any
fee payable to the arbitrator shall be borne equally by the parties.

                                   ARTICLE 4

                                      Use
                                      ---

     4.1  The Premises shall be used by Tenant solely as and for the Permitted
Use as set forth in the Reference Page and for no other purpose whatsoever.

     4.2  Tenant shall not use or permit the use of the Premises or any part
thereof in any way that would violate any of the covenants, agreements, terms,
provisions and conditions of this Lease or for any unlawful purposes or in any
unlawful manner or, except as otherwise provided in this paragraph 4.2, in
violation of the certificate of occupancy for the Premises or the Building (the
"Certificate of Occupancy"), or any ground or underlying leases which may now or
hereafter affect the Building or the Premises. Tenant acknowledges that it has
inspected the Certificate of Occupancy for the Building.  Landlord represents
that, at its sole cost and expense and with the cooperation of Tenant, it will
use its best efforts to modify the existing Certificate of Occupancy of the
Building as it relates to the 8/th/ floor of the Premises from the current
description of use as "Physical Culture Establishment" to "Offices and
Showrooms." Tenant shall not suffer or permit the Premises or any part thereof
to be used in any manner or anything to be done therein or anything to be
brought into or kept therein that, in the judgment of Landlord, shall in any way
impair or interfere with or tend to impair or interfere with (a) the character,
reputation or appearance of the Building as a high quality office building, (b)
any of the Building services, (c) the proper and economic heating, cleaning,
air-conditioning, ventilating or other servicing of the Building or the
Premises, (d) the use of any of the other areas of the Building by, or occasion
discomfort, inconvenience or annoyance to, any of the other tenants or occupants
of the Building, or (e) increase or tend to increase Landlord's costs of
operating the Building.

     4.3  If any governmental license or permit (other than a Certificate of
Occupancy for the Building) or any other license or permit required of all
tenants occupying space for executive and general office use in the Borough of
Manhattan shall be required for the proper and lawful conduct of Tenant's
specific business in the Premises or any part thereof or for Tenant's specific
occupancy of the Premises, Tenant at its expense shall procure and maintain and
comply with the terms and conditions of such license or permit and submit the
same to Landlord for inspection.

     4.4  Tenant acknowledges and agrees that the value of the Premises and the
reputation of the Landlord will be seriously injured if the Premises are used
for any obscene or pornographic

                                      -13-
<PAGE>

purposes or any sort of commercial sex establishment. Tenant agrees that it will
not bring or permit any obscene or pornographic material on the Premises, and
shall not permit or conduct any obscene, nude, or semi-nude live performances on
the Premises, nor permit use of the Premises for nude modeling, rap sessions, or
as a so-called rubber goods shop, or as a sex club of any sort, or as a "massage
parlor." Tenant agrees further that it will not permit any of these uses by any
sublessee or assignee of the Premises. This Section 4.4 shall directly bind any
successors in interest to the Tenant. Tenant agrees that if at any time it
violates any of the provisions of this Section 5.4, such violation shall be
deemed a breach of a substantial obligation of the terms of this Lease and
objectionable conduct. Pornographic material is defined for purposes of this
Section 5.4 as any written or pictorial matter with prurient appeal or any
objects or instrument that are primarily concerned with lewd or prurient sexual
activity. For the purposes of this Section 5.4 the term "obscene material" shall
have the meaning as set forth in New York State Penal Law Section 235.00.
Landlord represents that it shall use its best efforts to ensure that this
paragraph 4.4 shall be included in all other tenants' leases in the Building.

                                   ARTICLE 5

                         Alterations and Installations
                         -----------------------------

     5.1  Tenant shall make no Alterations in or to the Premises without
Landlord's prior written consent (including, without limitation, any work in
connection with the Tenant's initial occupancy of the Premises). Any approved
Alteration shall be performed only by contractors or mechanics first approved by
Landlord, provided, however, that any Alteration in or to the mechanical,
electrical, sanitary, heating, ventilating, air-conditioning or other systems of
the Building (including, without limitation, the fire-safety system) shall be
performed only by contractor(s) designated by Landlord. However, Tenant may use
a contractor not designated by Landlord provided Landlord gives Tenant its prior
written consent which consent shall not be unreasonably withheld. Every
Alteration shall be done at Tenant's sole cost and expense and at such times and
in such manner as Landlord may reasonably designate.  Notwithstanding anything
in this Article to the contrary, Tenant shall not be required to obtain the
Landlord's prior written approval for Alterations performed within the Premises
equal to or less than Fifty -thousand dollars ($50,000.00) in value. Tenant
shall nonetheless be required to provide Landlord with prior written notice of
any Alterations performed within the Premises equal to or less than Fifty -
thousand dollars ($50,000.00) in value.  In addition, Tenant shall not be
required to obtain the Landlord's prior written approval for Alterations which
are cosmetic in nature (i.e., carpeting, wallpapering and painting), are
entirely nonstructural, no part of which will tie into or connect with the
Building's Equipment (as hereinafter defined in Article 14.1) and do not require
Tenant to obtain a permit from the New York City Department of Buildings or any
successor agency ("Non-Consent Alterations"). Tenant shall nonetheless be
required to provide Landlord with at least ten (10) day's prior written notice
of any Non-Consent Alterations which are to be performed at the Premises.

     5.2  Every Alteration in or to the Premises shall be performed in
accordance with and shall conform to the Construction Rules and Regulations, and
the provisions of this Lease and shall be

                                      -14-
<PAGE>

effected solely in accordance with plans and specifications first approved in
writing by Landlord. Within ten (10) business days after submission to Landlord
of Tenant's plans and specifications, Landlord shall either approve Tenant's
plans and specifications or shall set forth in writing the particulars in which
Landlord does not approve same, in which latter case Tenant shall, if Tenant
wishes to proceed with such work, within five (5) days after Landlord's
notification, return to Landlord appropriate corrections thereto. Such
corrections shall be subject to Landlord's approval which approval shall not be
unreasonably withheld. Landlord's approval of Tenant's plans and specifications
shall not constitute a representation or guaranty by Landlord that Tenant's
Alterations comply with Legal Requirements. Such plans and specifications shall
be prepared at Tenant's sole cost and expense by a professional registered
architect and shall be complete, finished detailed architectural drawings and
specifications for the Alteration. Notwithstanding anything to the contrary
contained in this Lease, Landlord will not unreasonably withhold or delay its
consent to requests for Alterations provided they will not affect the outside of
the Building or adversely affect its structure, electrical, HVAC, plumbing,
sanitary, fire-safety or mechanical systems or not be in keeping with the
character of the Building.

     5.3  With respect to every Alteration:

          (a) All work shall be done in a good and workerlike manner and shall
not interfere with the operation of the Building or impose any additional
expense upon Landlord in the construction, maintenance, repair or operation of
the Building. If any additional expense shall be incurred by Landlord thereby,
Tenant shall pay such additional expense within fifteen (15) days after notice
by Landlord to Tenant.

          (b) Tenant will inform Landlord in writing of the names of any
contractor or subcontractor Tenant proposes to use in the Premises at least ten
days prior to the beginning of work by such contractor or subcontractor. Tenant
shall employ only contractors approved by Landlord in writing; and any
contractor employed by Tenant (and all subcontractors) shall agree to employ
only such labor as will not reasonably result in jurisdictional disputes or
strikes or cause disharmony with other workers employed at the Building. Upon
the happening of any such dispute, strike or disharmony, Tenant shall
immediately upon notice from Landlord discontinue the labor giving rise thereto.
In the event Tenant fails to do so, Landlord, in addition to any rights
available to it under this Lease and pursuant to Law, shall have the right to an
injunction with or without notice.

          (c) Tenant shall pay its contractors or subcontractors, as the work
progresses, the entire cost of supplying the materials and performing the work
shown on Tenant's approved plans and specifications subject to a reasonable
retainage. Within fifteen (15) days after each payment to its contractors are
due, Tenant shall furnish Landlord with evidence that such payment has been made
together with a waiver of lien by such contractor in the amount of such payment.

          (d) Tenant shall cause the Alteration to be installed in compliance
with Legal Requirements.

                                      -15-
<PAGE>

          (e) Tenant shall furnish to Landlord copies of all governmental
permits and authorizations that may be required in connection with any
Alteration. All such governmental permits and authorizations shall be obtained
by Tenant at its sole cost and expense and Tenant shall pay the cost of filing
Tenant's plans and specifications with the appropriate governmental authorities
in such form (building notice, alteration, or other) as Landlord may direct.

          (f) Tenant represents, warrants and covenants that the Alteration
will; (i) be of good quality and free from faults and defects, latent or
otherwise; (ii) be free and clear of Liens; (iii) conform to the plans and
specifications as approved by Landlord; and (iv) be fit for the intended use and
purpose.

          (g) Tenant shall make all reasonable efforts to keep the Building and
the Premises free and clear of all Liens for any work or material claimed to
have been furnished to Tenant or to the Premises on Tenant's behalf, and all
work to be performed by Tenant shall be done in a manner that will not
unreasonably interfere with or disturb other tenants or occupants of the
Building.

          (h) During the progress of the work to be done by Tenant, Landlord and
representatives of Landlord shall be permitted access and the opportunity to
inspect, at all reasonable times, but this provision shall not in any way
whatsoever create any obligation on Landlord to conduct any such inspection.

          (i) With respect to any Alteration costing more than $50,000.00
including the Alterations performed by Tenant prior to its initial occupancy,
Tenant agrees to pay to Landlord, as additional rent, within five calendar days
of demand therefor, an amount equal to Landlord's actual out-of-pocket costs and
expenses in connection with the Alteration in question not to exceed $5,000.00.

          (j) Prior to the commencement of any work, Tenant shall furnish to
Landlord original certificates of insurance naming the Landlord and its
designated managers and agents as additional insureds as its interest may appear
and evidencing the existence of:

          (i)  Workers' compensation insurance covering all persons employed for
     such work; and

          (ii) Comprehensive general liability (including contractual liability)
     and property damage insurance, with coverage of at least $5,000,000 per
     occurrence for bodily or personal injury (including death) and $1,000,000
     in respect of property damage, or in such higher amounts as Landlord may
     reasonably require.

Such insurance shall be maintained at all times during the performance of the
work and shall not be cancelable except on thirty (30) days' prior written
notice to Landlord.

                                      -16-
<PAGE>

          (k) Upon completion of each Alteration, Tenant shall remove, at its
sole cost, all debris from the Premises and clean the same. If the exterior
portions of the windows in the Building become soiled as a result of the
Alterations made by Tenant, Tenant shall reimburse Landlord, within fifteen days
after the rendition of a bill therefor, for Landlord's reasonable cost of
cleaning such windows.  Tenant shall pay for window cleaning only once during
each Alteration.

          (l) Upon completion of each Alteration, Tenant shall deliver "as-
built" plans and specifications for such Alteration to Landlord at Tenant's sole
cost and expense.

     5.4  Landlord shall not be responsible for any labor or materials furnished
to Tenant, or for delays of any kind experienced by Tenant's contractors. No
Lien for any labor, materials, or other services or things furnished to Tenant
shall attach to or affect Landlord's estate or interest in the Premises, the
Land and/or the Building. Tenant agrees to discharge, at Tenant's expense
(whether by payment, bonding, or otherwise) every Lien filed against the
Premises, the Land and/or the Building for work claimed to have been done for or
materials claimed to have been furnished to Tenant, within thirty (30) days
after receiving notice of the same. Tenant shall require that all contractors
and subcontractors engaged in connection with Tenant's Alterations indemnify and
hold Landlord harmless against any and all claims for injury to persons or
damage to property by reason of such contractor's or subcontractor's use of the
Premises or performance of the work, including any claims, fines and penalties
imposed due to a failure to comply with Laws.

     5.5  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.

     5.6  All fixtures, improvements, Alterations, installations, additions,
paneling, permanent partitions, doors, railings and like installations installed
in the Premises at any time, either by Tenant or by Landlord or others on
Tenant's behalf and whether installed or purchased at Landlord's or Tenant's
expense (collectively, the "Leasehold Improvements") shall become the property
of Landlord upon installation. The Leasehold Improvements shall remain upon, and
shall be surrendered with, the Premises unless Landlord elects, by notice to
Tenant given at the time Landlord responds to the submission of Tenant's Plans
to perform Alterations in accordance with this Article to have Tenant remove all
or part of the Leasehold Improvements which are considered, in Landlord's
reasonable judgment, special or unique in nature. In such event, prior to the
expiration or sooner termination of this Lease and at Tenant's sole cost and
expense, Tenant shall remove all such Leasehold Improvements in Landlord's
reasonable judgment, special or unique in nature as Landlord has specified for
removal in such notice and shall repair all damage to the Premises or to the
Building due to such removal and restore the same to the condition existing
immediately prior to the installation of such Leasehold Improvements.
Notwithstanding anything contained in this section to the contrary, (i) Tenant's
obligation to remove Alterations and/or improvements is limited to Alterations
and/or  improvements installed by or at the request of Tenant and shall not
include the Landlord's Work or Alterations performed by Tenant utilizing the
Landlord's Contribution, as

                                      -17-
<PAGE>

defined in the Work Letter annexed hereto as Exhibit A and (ii) Tenant shall be
permitted on the Expiration Date to remove the pendant lighting and audio visual
equipment installed by Tenant in the Premises.

     5.7  If any Alterations, installations, additions, improvements or other
property that Tenant shall have the right to remove or be requested by Landlord
to remove are not removed on or prior to the expiration of the  Term of this
Lease, Landlord shall have the right to remove the property and to dispose of
the same without accountability to Tenant and at the sole cost and expense of
Tenant. In case of any damage to the Premises or the Building resulting from the
removal of the property, Tenant shall repair such damage or, in default thereof,
shall reimburse Landlord for Landlord's cost in repairing such damage. Tenant's
obligations under this section shall survive the expiration or other termination
of this Lease.

                                   ARTICLE 6

                                    Repairs
                                    -------

     6.1  (a)  Except as provided herein, Tenant shall, at its sole cost and
expense, take good care of the Premises and the fixtures and appurtenances
therein (including, without limitation, bathroom and plumbing fixtures and
appurtenances) and make all repairs thereto as and when needed to preserve them
in good working order and condition and maintain the Premises in a condition
consistent with comparable buildings. Tenant, at its sole cost and expense,
shall promptly replace all damaged or broken doors and glass in and about the
Premises. All damage or injury to the Premises and to its fixtures,
appurtenances and equipment or to the Building or to its fixtures, appurtenances
and equipment caused by or which arises out of (i) Tenant moving property in or
out of the Building, or (ii) Tenant's installation or removal of furniture,
fixtures or other property, or (iii) the performance or existence of any
Alterations performed in the Premises by or on behalf of Tenant or anyone
claiming possession through Tenant or (iv) Tenant's installation, use or
operation of Tenant's property in the Premises or (v) from any other cause of
any other kind or nature whatsoever due to carelessness, omission, neglect,
improper conduct or other cause on the part of Tenant, its servants, employees,
agents, visitors, or licensees, shall be repaired, restored or replaced promptly
at Tenant's sole cost and expense to the reasonable satisfaction of Landlord.
Any repairs required to be made by Tenant to the mechanical, electrical,
plumbing, sanitary, heating, ventilating, air-conditioning, fire safety or other
systems of the Building shall be performed only by contractor(s) designated by
Landlord. Any other repairs in or to the Building and the facilities and systems
for which Tenant is responsible may be performed by Landlord at Tenant's expense
and may be charged to Tenant as additional rent in the event Tenant fails to
perform such repairs; All repairs, restorations and replacements made by Tenant
shall be in quality and class equal to the original work or installations and
shall be of a quality at least comparable to the quality installed in the
Building.  If Tenant fails to make such repairs, restoration or replacements,
same may be made by Landlord at the expense of Tenant and such expense shall be
collectible as additional rent and shall be paid by Tenant within thirty (30)
days after rendition of a bill therefor.

                                      -18-
<PAGE>

     6.2  (a) Tenant shall not place a load upon any floor of the Premises
exceeding the floor load per square foot area that such floor was designed to
carry and that is allowed by law. If Tenant shall desire a floor load in excess
of that which such floor was designed to carry and which is allowed by law,
Tenant shall submit plans and specifications for such floor load to Landlord for
Landlord's review and approval. Tenant shall pay all actual out-of-pocket costs
and expenses incurred by Landlord in connection with its review of Tenant's
plans and specifications.

          (b) Landlord shall not unreasonably withhold or delay its consent to
Tenant's request to strengthen and reinforce the floor to provide the live load
desired so long as Landlord's architects and engineers, in their sole
discretion, find that the work necessary to increase such floor load (i) does
not affect adversely the structure of the Building, (ii) will not interfere with
the amount or availability of any space adjoining alongside, above or below the
Premises, (iii) will not interfere with the occupancy of other tenants in the
Building and (iv) may be accomplished without disturbing the load-bearing
columns, walls or configuration of the Building. Tenant's plans and
specifications shall also provide for the restoration of the floor to its
condition prior to such requested strengthening and reinforcement. Tenant shall
agree to pay for or reimburse Landlord on demand for the reasonable cost of such
strengthening and reinforcement and for the reasonable cost of restoration of
the floor to its condition prior to such strengthening and reinforcement, as
well as any other reasonable costs to and reasonable expenses of Landlord
occasioned by or resulting from such strengthening or reinforcement.

     6.3  Business machines and mechanical equipment used by Tenant that cause
excess vibration, beyond what is typical for similar office space, noise, cold
or heat that may be transmitted to the Building structure or to any leased space
to such a degree as to be objectionable to Landlord or to any other tenant in
the Building shall be placed and maintained by Tenant at its expense in settings
of cork, rubber or spring type vibration eliminators sufficient to absorb and
prevent such vibration or noise, or prevent transmission of such cold or heat.
Tenant acknowledges that the operation of elevators, air-conditioning and
heating equipment will cause some vibration, noise, heat or cold that may be
transmitted to other parts of the Building and Premises and Landlord shall make
reasonable efforts to minimize same.

     6.4  Except as otherwise specifically provided in this Lease, there shall
be no allowance to Tenant for a diminution of rental value and no liability on
the part of Landlord by reason of inconvenience, annoyance or injury to business
arising from the making of any repairs, alterations, additions or improvements
in or to any portion of the Building or the Premises or in or to fixtures,
appurtenances or equipment thereof, including the erection or operation of a
crane, derrick or sidewalk shed. Landlord shall exercise reasonable diligence so
as to minimize any interference with Tenant's business operations and shall
exercise reasonable diligence not to block Tenant's windows (except due to or as
a result of a Legal Requirement or Landlord's necessary work, maintenance or
repairs to the Building), but shall not be required to perform the same on an
overtime or premium pay basis.

                                      -19-
<PAGE>

     6.5  Tenant will not clean, nor require, permit, suffer or allow any window
in the Premises to be cleaned from the outside in violation of Section 202 of
the Labor Law or any other applicable Legal Requirement.

                                   ARTICLE 7

                              Requirements of Law
                              -------------------

     7.1  If Tenant receives any notice of any violation of any Legal
Requirement, Tenant shall give prompt written notice thereof to Landlord.
Tenant, at its sole cost and expense, shall comply with all Legal Requirements
which shall impose any violation, order or duty upon Landlord or Tenant with
respect to the Premises (including, without limitation, the performance of any
Alterations under the Americans with Disabilities Act of 1990) or the use or
occupation thereof (in which event Tenant shall effect such compliance at its
sole cost and expense) or if, as a result of any act or omission by Tenant or
violation of this Lease by Tenant, any Legal Requirement is violated, Tenant, at
its sole cost and expense, shall cause any such violation to be promptly cured.
The foregoing shall include any structural alterations necessary to effect such
a cure.

          (a) Without limiting the generality of Section 7.1, Tenant, at its
sole cost and expense, shall comply with all Legal Requirements regarding the
collection, sorting, separation and recycling of waste products, garbage, refuse
and trash from within the Premises or produced by Tenant. Tenant shall sort and
separate such waste products, garbage, refuse and trash into such categories as
provided by any Legal Requirements. Each separately sorted category of waste
products, garbage, refuse and trash from within the Premises shall be placed in
separate receptacles reasonably approved by Landlord. Such separate receptacles
may, at Landlord's option, be removed from the Premises in accordance with a
collection schedule prescribed by any Legal Requirements. Tenant, at Tenant's
sole cost and expense, represents that it shall arrange for the collection of
its waste products, garbage, refuse and trash utilizing a contractor reasonably
satisfactory to Landlord.

     7.2  Notwithstanding the provisions of Sections 7.1 and 7.2 hereof, Tenant,
at its own cost and expense, in its name and/or (whenever necessary) Landlord's
name, may contest, in any manner permitted by law (including appeals to a court
or governmental department or authority having jurisdiction in the matter), the
validity or the enforcement of any governmental act, regulation or directive
with which Tenant is required to comply pursuant to this Lease, and may defer
compliance therewith during the course of such contest, provided that (a) such
non-compliance shall not subject Landlord to criminal prosecution or subject the
Land and/or Building to Lien or sale, (b) such non-compliance shall not be in
violation of any fee mortgage or of any ground or underlying lease or any
mortgage thereon, (c) Tenant shall first deliver to Landlord a surety bond
issued by a surety company of recognized responsibility, or other security
satisfactory to Landlord, indemnifying and protecting Landlord against any loss
or injury by reason of such non-compliance, and (d) Tenant shall prosecute such
contest promptly and diligently to its conclusion.

                                      -20-
<PAGE>

     7.3  Landlord, without expense or liability to it, shall cooperate with
Tenant and execute any documents or pleadings required for such purpose,
provided that Landlord shall be reasonably satisfied that the facts set forth in
any such documents or pleadings are accurate.

                                   ARTICLE 8

                   Insurance, Loss, Reimbursement Liability
                   ----------------------------------------

     8.1  Tenant shall not do, permit or suffer to be done any act or thing upon
the Premises that would invalidate or be in conflict with New York standard fire
and property damage insurance policies covering the Building, and fixtures and
property therein, or that would increase the rate of insurance applicable to the
Building to an amount higher than it otherwise would be; and Tenant neither
shall do nor shall Tenant permit to be done any act or thing upon the Premises
that shall or might subject Landlord to any liability or responsibility for
injury to any person or persons or to property by reason of any business or
operation being carried on within the Premises.

     8.2  If, as a result of any act or omission by Tenant or violation of this
Lease, the rate of any insurance applicable to the Building shall be increased
to an amount higher than it otherwise would be, Tenant shall reimburse Landlord
for all increases of Landlord's insurance premiums so caused; such reimbursement
to be additional rent payable upon the first day of the month following any
outlay by Landlord for such increased insurance premiums. In any action or
proceeding wherein Landlord and Tenant are parties, a schedule or "make-up" of
rates for the Building or Premises issued by the body making insurance rates for
the Premises, shall be presumptive evidence of the facts therein stated and of
the several items and charges in the insurance rate then applicable to the
Premises.

     8.3  Landlord or its agents shall not be liable for any injury or damage to
persons or property (including, but not limited to, loss of profits and injury
to business) resulting from fire, explosion, falling plaster, steam, gas,
electricity, water, rain or snow or leaks from any part of the Building, or from
the pipes, appliances or plumbing works or from the roof, street or subsurface
or from any other place or by dampness or by any other cause of any nature,
unless any of the foregoing shall be caused by or due to the negligence and
willful misconduct of Landlord, its agents, servants or employees.

     8.4  Subject to Article 6.4 herein, Landlord or its agents shall not be
liable for any damage which Tenant may sustain, if at any time any window of the
Premises is broken, or temporarily or permanently (restricted to windows on a
lot line, if permanently) closed, darkened or bricked up for any reason
whatsoever, except only Landlord's arbitrary acts if the result is permanent,
and Tenant shall not be entitled to any compensation therefor or abatement of
rent or to any release from any of Tenant's obligations under this Lease, nor
shall the same constitute an eviction.

     8.5  Tenant shall reimburse Landlord for all expenses, damages or fines
incurred or suffered by Landlord, by reason of any breach, violation or non-
performance by Tenant, or its agents,

                                      -21-
<PAGE>

servants or employees, of any covenant or provision of this Lease. Subject to
the provisions of Section 8.1 hereof, where applicable, Tenant shall have the
right, at Tenant's own cost and expense, to participate in the defense of any
action or proceeding brought against Landlord, and in negotiations for
settlement thereof if, pursuant to this Section 8.5, Tenant would be obligated
to reimburse Landlord for expenses, damages or fines incurred or suffered by
Landlord.

     8.6  Tenant shall give Landlord notice in case of fire or accidents in the
Premises promptly after Tenant becomes aware of such event.

     8.7  Landlord's agents, officers, directors and members (and, in case
Landlord shall be a joint venture, partnership, tenancy-in-common, association
or other form of joint ownership, the members of any such joint venture,
partnership, tenancy-in-common, association or other form of joint ownership)
shall have absolutely no personal liability with respect to any provision of
this Lease or any obligation or liability arising therefrom or in connection
therewith. Tenant shall look solely to Landlord's estate and interest in the
Land and Building, or the lease of the Building or of the Land and Building, and
the Premises, for the satisfaction of any right or remedy of Tenant for the
collection of a judgment (or other judicial process) requiring the payment of
money by Landlord. No other property or assets of Landlord or any agent,
officer, director or member shall be subject to levy, execution, attachment, or
other enforcement procedure for the satisfaction of Tenant's remedies under or
with respect to this Lease, the relationship of Landlord and Tenant hereunder,
or Tenant's use and occupancy of the Premises, or any other liability of
Landlord to Tenant. However, nothing contained in this Section shall be
construed to permit Tenant to offset against rents due a successor landlord a
judgment (or other judicial process) requiring the payment of money by reason of
any default of a prior landlord.

     8.8  (a)  Landlord shall include in its insurance policies appropriate
clauses pursuant to which the insurance companies (i) waive all right of
subrogation against Tenant with respect to losses payable under such policies
and/or (ii) agree that such policies shall not be invalidated should the insured
waive in writing prior to a loss any or all right of recovery against any party
for losses covered by such policies.

          (b)  Tenant shall obtain on or before the Commencement Date and shall
keep in force during the  Term hereof, all-risk insurance in an amount equal to
the full replacement cost of Tenant's furniture, furnishings and other removable
personal property and of all fixtures including leasehold improvements and
betterments. Tenant shall include in such insurance policy or policies
appropriate clauses pursuant to which the insurance company or companies (i)
waive the right of subrogation against Landlord and/or any tenant of space in
the Building with respect to losses payable under such policy or policies and/or
(ii) agree that such policy or policies shall not be invalidated should the
insured waive in writing prior to a loss any or all right of recovery against
any party for losses covered by such policy or policies.

          (c)  Provided that Landlord's right of full recovery under its policy
or policies aforesaid is not adversely affected or prejudiced thereby, Landlord
hereby waives any and all right

                                      -22-
<PAGE>

of recovery that it might otherwise have against Tenant, its servants, agents
and employees, for loss or damage occurring to the Building and the fixtures,
appurtenances and equipment therein, to the extent of the net proceeds of
insurance actually received by Landlord as a result of such loss or damage,
notwithstanding that such loss or damage may result from the negligence or fault
of Tenant, its servants, agents or employees. Provided that Tenant's right of
full recovery under its aforesaid policy or policies is not adversely affected
or prejudiced thereby, Tenant hereby waives any and all right of recovery which
it might otherwise have against Landlord, its servants, and employees, and
against every other tenant in the Building who shall have executed a similar
waiver as set forth in this section for loss or damage to, Tenant's furniture,
furnishings, fixtures and other property removable by Tenant under the
provisions hereof to the extent of the net proceeds of insurance actually
received by Tenant as a result of such loss or damage, notwithstanding that such
loss or damage may result from the negligence or fault of Landlord, its
servants, agents or employees, or such other tenant and the servants, agents or
employees thereof.

     8.9  (a)  Tenant shall provide on or before the Commencement Date and shall
keep in force during the  Term hereof for the benefit of Landlord and Tenant a
comprehensive general liability insurance policy (including contractual
liability) protecting Landlord and Tenant against any liability whatsoever,
arising out of the use of the Premises or any appurtenances thereto or
occasioned by any occurrence on or about the Premises or any appurtenances
thereto. Such policy shall be not less than the amount of $5,000,000 per
occurrence for bodily or personal injury (including death) and in the amount of
$1,000,000 in respect of property damage which amounts shall be subject to
increase from time to time as Landlord may reasonably request (and within 30
days after such request, Tenant shall furnish Landlord with evidence of such
increase in coverage). Tenant shall provide on or before the Commencement Date
and shall keep in force during the  Term hereof for the benefit of Landlord and
Tenant a sprinkler leakage/water damage policy.

          (b)  All insurance required by this Lease shall be evidenced by valid
and enforceable policies issued by companies (i) licensed to do business in the
State of New York and (ii) having a financial size category of not less than XII
and with general policy holders rating of not less than "A" as rated by "Best's"
insurance reports. All insurance policies shall name Landlord and its designated
managers and agents as additional insureds. The insurance required by this
Article may be carried under a blanket policy covering the Premises and other
locations of Tenant. if any. Prior to the time such insurance is first required
to be carried by Tenant and thereafter, at least 15 days prior to the effective
date of any such policy, Tenant shall deliver to Landlord either a duplicate
original of the aforesaid policies or a certificate(s) evidencing such
insurance. Said certificate(s) shall contain an endorsement that such insurance
may not be canceled except upon 30 days' written notice to Landlord. Tenant's
failure to provide and keep in force the aforementioned insurance shall be
regarded as a default hereunder entitling Landlord to exercise any or all of the
remedies provided in this Lease in the event of Tenant's default.

                                      -23-
<PAGE>

                                   ARTICLE 9

                         Damage by Fire or Other Cause
                         -----------------------------

     9.1  If the Premises or any part thereof shall be damaged by fire or other
casualty Tenant shall give immediate notice thereof to Landlord and this Lease
shall continue in full force and effect except as hereinafter set forth.

     9.2  (a)  If the Premises are partially damaged or rendered partially
untenantable by fire or other casualty, the damage thereto shall be repaired by
and at the expense of Landlord and the Fixed annual rent and the additional rent
payable under Articles 3 and 4 until such repair shall be substantially
completed shall be apportioned from the day following the casualty according to
the part of the Premises that is tenantable.

          (b)  If the Premises are totally or substantially damaged or are
rendered wholly or substantially untenantable by fire or other casualty, then
the fixed annual rent and the additional rent payable under Articles 3 and 4
shall be paid up to the time of the casualty and thenceforth shall cease until
the date when the Premises shall have been repaired and restored by Landlord,
subject to Landlord's right to elect not to restore the same as hereinafter
provided.

          (c)  If the Premises are totally or substantially damaged or are
rendered wholly or substantially untenantable (whether or not the Premises are
damaged) or if the Building shall be so damaged that Landlord shall decide to
demolish it or to rebuild it, or if at least 50% of the floor area of the
Premises is damaged or destroyed during the last 18 months of the  Term of this
Lease, then, in any of such events, Landlord may elect to terminate this Lease
by written notice to Tenant. Such notice shall be given by Landlord within 90
days after such fire or casualty specifying a date for the expiration of the
Lease, which date shall not be more than 60 days after the giving of such
notice, and upon the expiration date specified in such notice the  Term of this
Lease shall expire as fully and completely as if such date were the date set
forth above for the termination of this Lease and Tenant shall forthwith quit,
surrender and vacate the Premises without prejudice however to Landlord's rights
and remedies against Tenant under the Lease provisions in effect prior to such
termination. Any rent owing shall be paid up to such date (subject to abatement
as provided in subparagraph 9.2) and any payments of rent made by Tenant that
were on account of any period subsequent to such date shall be returned to
Tenant within thirty (30) days of the Expiration Date. Unless Landlord shall
serve a termination notice as provided for herein, Landlord shall make the
repairs and restorations under the conditions of (a) and (b) hereof, with all
reasonable expedition during Business Days and Business Hours, subject to delays
due to adjustment of insurance claims, labor troubles and causes beyond
Landlord's control. After any such casualty, Tenant shall cooperate with
Landlord's restoration by removing from the Premises as promptly as reasonably
possible, all of Tenant's salvageable inventory and movable equipment, furniture
and other property. Tenant's liability for rent shall resume five days after
written notice from Landlord that the Premises are substantially ready for
Tenant's occupancy and Landlord has sent written notice thereof to Tenant.

     9.3  Nothing contained in this Article 9 shall relieve Tenant from
liability that may exist as a result of damage from fire or other casualty.

                                      -24-
<PAGE>

     9.4  No damages, compensation or claim shall be payable by Landlord for
inconvenience, loss of business or annoyance arising from any repair or
restoration of any portion of the Premises or of the Building pursuant to this
Article 9.  However, with respect to any repair or restoration to be performed
by Landlord under this Article, Landlord shall make reasonable efforts to
minimize disruption to Tenant's business.

     9.5  Notwithstanding any of the foregoing provisions of this Article 9, if
Landlord or the lessor of any superior lease or the holder of any superior
mortgage shall be unable to collect all of the insurance proceeds (including
rent insurance proceeds) applicable to damage or destruction of the Premises or
the Building by fire or other cause, by reason of some action or inaction on the
part of Tenant or any of its employees, agents or contractors, then, without
prejudice to any other remedies that may be available against Tenant, there
shall be no abatement of Tenant's rents, but the total amount of such rents not
abated (that otherwise would have been abated) shall not exceed the amount of
uncollected insurance proceeds.

     9.6  Landlord will not carry separate insurance of any kind on Tenant's
property or leasehold improvements, alterations, installations or additions made
to the Premises, and, except as provided by law or by reason of its breach of
any of its obligations hereunder, shall not be obligated to repair any damage
thereto or replace the same. Tenant shall maintain insurance on Tenant's
property, leasehold improvements, alterations, installations and additions and
Landlord shall not be obligated to repair any damage thereto or replace the
same.

     9.7  The provisions of this Article 9 shall be considered an express
agreement governing any cause of damage or destruction of the Premises by fire
or other casualty, and Section 227-a the Real Property Law of the State of New
York, providing for such a contingency in the absence of an express agreement,
and any other law of like import, now or hereafter in force, shall have no
application in such case.

                                  ARTICLE 10

                   Assignment, Mortgaging, Subletting, etc.
                   ---------------------------------------

     10.1 Tenant shall not by operation of law or otherwise (a) assign or
otherwise transfer this Lease or the term and estate hereby granted, (b) sublet
the Premises or any part thereof or allow the same to be used or occupied by
others, (c) mortgage, pledge or encumber this Lease or the Premises or any part
thereof in any manner by reason of any act or omission on the part of Tenant, or
(d) advertise, or authorize a broker to advertise, for a subtenant or an
assignee, without, in each instance, obtaining the prior written consent of
Landlord, except as otherwise expressly provided in this Article 10.  For
purposes of this Article 10, the transfer of a majority of the issued and
outstanding capital stock of any corporate tenant shall not be deemed an
assignment of this Lease.  Except as otherwise provided in this Article 10, an
agreement by (i) any other person or entity, directly or indirectly, to assume
Tenant's obligations under this Lease shall be deemed an assignment, (ii) any

                                      -25-
<PAGE>

person or legal representative of Tenant, to whom Tenant's interest under this
Lease passes by operation of law, or otherwise, and (iii) a modification,
amendment or extension of a sublease shall be deemed a sublease. Tenant agrees
to furnish to Landlord upon demand at any time such information and assurances
as Landlord may reasonably request that neither Tenant, nor any previously
permitted subtenant, has violated the provisions of this Section 10.1.

     10.2  Subject to the following sentence, the provisions of Section 10.1
hereof shall not apply to transactions with a corporation into or with which
Tenant is merged or consolidated or with an entity to which substantially all of
Tenant's assets are transferred (for a bonafide business purpose and not to
avoid liability under the Lease) provided that the assignee has a net worth at
least equal to or in excess of the net worth of Tenant immediately prior to such
merger or transfer and Tenant provides Landlord at least fifteen (15) days prior
written notice of such merger, consolidation or transfer or to an "affiliate" of
Tenant. For the purposes hereof an "affiliate" of Tenant shall mean as to Tenant
or any other entity, an entity that controls, is controlled by, or is under
common control with, Tenant or such other entity, as the case may be.  "Control"
shall mean direct ownership of more than fifty percent  (50%) of the voting
shares or other voting interests of the controlled entity, and "under common
control with" shall mean an entity more than fifty percent (50%) of the voting
shares or other voting interests of which are directly owned by an entity which
directly owns more than fifty percent (50%) of the voting shares or other voting
interests in Tenant or such other entity, as the case may be.    Nothing in this
Section 10.2 shall permit Tenant or any successor to use or occupy the Premises
for any purpose other than the purposes stated in Article 4 of this Lease.

     10.3  Any assignment or transfer, whether made with Landlord's consent as
required by Section 10.1 or without Landlord's consent pursuant to Section 10.2,
shall be made only if, and shall not be effective until, the assignee shall
execute, acknowledge and deliver to Landlord a recordable agreement, in form and
substance reasonably satisfactory to Landlord, whereby the assignee shall assume
the obligations and performance of this Lease and shall agree to be bound by and
upon all of the covenants, agreements, terms, provisions and conditions hereof
on the part of Tenant to be performed or observed and whereby the assignee shall
agree that the provisions of Section 10.3 hereof shall, notwithstanding such an
assignment or transfer, continue to be binding upon it in the future. Tenant
covenants that, notwithstanding any assignment or transfer, whether or not in
violation of the provisions of this Lease, and notwithstanding the acceptance of
rent by Landlord from an assignee or transferee or any other party, Tenant shall
remain fully and primarily liable for the payment of the rent due and to become
due under this Lease and for the performance of all of the covenants,
agreements, terms, provisions and conditions of this Lease on the part of Tenant
to be performed or observed.

     10.4  The liability of Tenant, and the due performance by Tenant of the
obligations on its part to be performed under this Lease, shall not be
discharged, released or impaired in any respect by an agreement or stipulation
made by Landlord or any grantee or assignee of Landlord, by way of mortgage, or
otherwise, extending the time of, or modifying any of the obligations contained
in this Lease, or by any waiver or failure of Landlord to enforce any of the
obligations on Tenant's part to be performed under this Lease, and Tenant shall
continue to be liable hereunder. If any such

                                      -26-
<PAGE>

agreement or modification operates to increase the obligations of a tenant under
this Lease, the liability under this Section 10.4 of Tenant named in this Lease
or any of its successors in interest (unless such party shall have expressly
consented in writing to such agreement or modification) shall continue to be no
greater than if such agreement or modification had not been made.

     10.5  Landlord shall not withhold or delay its consent unreasonably to an
assignment of this Lease or a subletting of the whole or a part of the Premises
for the remainder of the Term of this Lease, provided:

           (a) Tenant shall furnish Landlord with the name and business address
of the proposed subtenant or assignee, information with respect to the nature
and character of the proposed subtenant's or assignee's business, or activities,
such references and current financial information with respect to net worth,
credit and financial responsibility as are reasonably satisfactory to Landlord,
and an executed counterpart of the sublease or assignment agreement as soon as
that agreement is consummated, but no less than thirty (30) days prior to the
effective date of the contemplated sublease or assignment, and all ancillary
agreements with the proposed sublessee or assignee;

           (b) the proposed subtenant or assignee is a party whose financial net
worth at the time of the contemplated sublease or assignment is greater than
Tenant's net worth as of (i) the Commencement Date or (ii) at the time of the
contemplated sublease or assignment, and whose credit and financial condition
is, considering the responsibilities involved, reasonably satisfactory to
Landlord;

           (c) the nature and character of the proposed subtenant or assignee,
its business or activities and intended use of the Premises is, in Landlord's
reasonable judgment, in keeping with the standards of the Building and the floor
or floors on which the Premises are located;

           (d) the proposed subtenant or assignee is not then an occupant of any
part of the Building and the Landlord does not then have any comparable space
available in the Building to the space in which Tenant is seeking to sublet or
assign or the proposed subtenant or assignee is not a party who dealt with
Landlord or Landlord's agent (directly or through a broker) with respect to
space in the Building during the nine (9) months immediately preceding Tenant's
request for Landlord's consent;

           (e) all costs incurred with respect to providing reasonably
appropriate means of ingress and egress from the sublet space or to separate the
sublet space from the remainder of the Premises shall, subject to the provisions
of Article 5 with respect to alterations, installations, additions or
improvements, be borne by Tenant;

           (f) each sublease shall state specifically that (i) it is subject to
all of the terms, covenants, agreements, provisions and conditions of this
Lease, (ii) the subtenant or assignee, as the case may be, will not have the
right to a further assignment thereof or sublease or assignment

                                      -27-
<PAGE>

thereunder, or to allow the Premises to be used by others, without the consent
of Landlord in each instance in accordance with this Lease, (iii) a consent by
Landlord thereto shall not be deemed or construed to modify, amend or affect the
terms and provisions of this Lease, or Tenant's obligations hereunder, which
shall continue to apply to the Premises, and the occupants thereof, as if the
sublease or assignments had not been made, (iv) if Tenant defaults in the
payment of any rent, Landlord is authorized to collect any rents due or accruing
from any assignee, subtenant or other occupant of the Premises and to apply the
net amounts collected to the fixed annual rent and additional rent reserved
herein and (v) the receipt by Landlord of any amounts from an assignee or
subtenant, or other occupant of any part of the Premises shall not be deemed or
construed as releasing Tenant from Tenant's obligations hereunder or the
acceptance of that party as a direct tenant;

           (g) Tenant, together with requesting Landlord's consent hereunder,
shall have paid Landlord any actual out of pocket costs incurred by Landlord to
review the requested consent including, without limitation, any attorney's fees
incurred by Landlord not to exceed $5,000.00;

           (h) the proposed subtenant or assignee is not (i) an employment or
recruitment agency other than executive offices; (ii) a school, college,
university or educational institution whether or not for profit; (iii) a
government or any subdivision or agency thereof; (iv) engaged in the business of
providing office space and facilities to sublessees or licensees; or (v) engaged
in the business of public stenographer or typist, barber shop, beauty shop,
beauty parlor or shop, telephone or telegraph agency, telephone or secretarial
service, messenger service, commercial document reproduction or offset printing
service or public vending machine service;

           (i) in the case of a subletting of a portion of the Premises, the
portion so sublet shall be regular in shape and suitable for normal renting
purposes;

           (j) there shall be no more than one subtenant per floor in the
Premises at any time.

     10.6  If Landlord shall elect to have Tenant execute and deliver a sublease
pursuant to any of the provisions of this Section, said sublease shall be in a
form reasonably satisfactory to Landlord's counsel.

     10.7  If Landlord shall give its consent to any assignment of this Lease or
to any sublease, Tenant, in consideration therefor, shall pay the following to
Landlord, as additional rent:

           (i)  in the case of an assignment, an amount equal to twenty percent
(20%) of gross amount paid, and any other consideration paid to Tenant by the
assignee in excess of the then fixed annual rent for or by reason of such
assignment (excluding all sums paid for the sale or rental of Tenant's fixtures,
leasehold improvements, equipment, furniture, furnishings or other personal
property and any and all of the Tenant's actual out of pocket costs in
connection with such assignment); and

                                      -28-
<PAGE>

          (ii) in the case of a sublease, twenty percent (20%) of the gross
amount paid and other consideration payable under the sublease to Tenant by the
subtenant in excess of the then fixed annual rent accruing during the term of
the sublease in respect of the subleased space (at the rate per square foot
payable by Tenant hereunder) pursuant to the terms hereof (excluding any and all
sums paid for the sale or rental of Tenant's fixtures, leasehold improvements,
equipment, furniture or other personal property, and any and all of the Tenant's
actual out of pocket costs in connection with such sublease, including but
limited to costs associated with altering and preparing the Premises for the
sublessee, brokers' commissions, attorneys' fees and disbursements, and any and
all other expenses chargeable against the Premises and the rental thereof).

For example, in the event the Tenant, with Landlord's consent, is permitted to
sublease or assign the 7/th/ floor of the Premises after the Third Anniversary
of the Rent Commencement Date but prior to the Fourth Anniversary of the Rent
Commencement Date to a permitted sublessee or assignee for $45.00 per square
foot or $495,000.00 per annum, then Tenant, pursuant to this paragraph 10.8(i)
and (ii), would pay to Landlord, in additional to the then fixed annual rent,
the sum certain amount of $12,456.02 ($495,000.00 - $432,719.89 = $62,280.11 x
 .2 = 12,456.02) for the first year of the sublease or for each year remaining on
the Term of this Lease after the 7/th/ floor of the Lease has been assigned, as
the case may be.

The sums payable under this Section 10.8 shall be paid to Landlord as and when
paid by the assignee or subtenant to Tenant.

     10.8  Landlord shall have no liability for brokerage commissions incurred
with respect to any assignment of this Lease or any subletting of all or any
part of the Premises by or on behalf of Tenant. Tenant shall pay, and shall
indemnify and hold Landlord harmless from and against, any and all cost, expense
(including, without limitation, reasonable attorneys' fees, costs and
disbursements) and liability in connection with any compensation, commissions or
charges claimed by any broker or agent with respect to any such assignment or
subletting.

     10.9  Should this Lease grant or provide Tenant (i) any options for Tenant
to extend the  Term hereof, (ii) rights to expand into additional space within
the Building, (iii) the right to require Landlord to perform any work within the
Building (other than ordinary repair obligations of Landlord) or the Premises to
improve the Premises or the Building for the benefit of Tenant, or (iv) rental
concessions, such rights shall be deemed personal to Tenant and shall not inure
to the benefit of any permitted assignee or sublessee, except an assignee or
sublessee under Section 10.2  hereof.

     10.10  The listing of any name other than that of Tenant, whether on the
doors of the Premises or the Building directory, or otherwise, shall not operate
to vest any right or interest in this Lease or in the Premises in the person or
entity therein named, nor shall it be deemed to be the consent of Landlord to
any assignment or transfer of this Lease or to any sublease of the Premises or
to the use or occupancy thereof by others.  Tenant's permitted subtenants shall
be allowed, with

                                      -29-
<PAGE>

the Landlord's prior written consent, which consent shall not be unreasonably
withheld and subject to Landlord's reasonable fee, to add the subtenant's name
to the Building's directory.

                                   ARTICLE 11

                         Electricity/Telecommunications
                         ------------------------------

     11.1  Tenant shall arrange to obtain electric energy directly from the
public utility company furnishing electric energy to the Building. Such electric
energy shall be furnished to Tenant by means of the then existing building
system feeders, risers and wiring to the extent that the same are, in Landlord's
reasonable judgment, available, suitable and safe for such purpose. All meters
and additional panel boards, feeders, risers, wiring and other conductors and
equipment whatsoever which may be required to obtain electric energy directly
from such public utility company, whether currently available for Tenant's use,
or requiring installation, shall be furnished and installed by and at Tenant's
sole cost and expense.  Landlord does not make any representations or warranties
as to the level of electrical capacity suitable for Tenant's Permitted Use of
the Premises other than 400 amperes of electricity are available for Tenant's
use per floor.

     11.2  Tenant, at its sole cost and expense, shall furnish and install all
replacement lighting tubes, lamps, bulbs and ballasts required in the Premises.
Landlord shall not be liable in any way to Tenant for any failure or defect in
the supply or character of electric energy furnished to the Premises by reason
of any requirement, act or omission of the public utility serving the Building
or for any other reason not caused by Landlord's gross-negligence or willful
misconduct, and in no event shall Landlord be liable to Tenant for indirect,
consequential or punitive damages, including, without limitation, loss of
profits.. Tenant shall pay for the cost of electricity consumed by any air-
conditioning equipment servicing the Premises irrespective of whether any such
equipment is located in the Premises or in any other portion of the Building.
The term "air-conditioning equipment" as used herein shall be deemed to include,
without limitation, all components and auxiliary equipment used in connection
with air-conditioning equipment servicing the Premises.

     11.3  Tenant's use of electric energy in the Premises shall not at any
time, in the judgment of Landlord, (a) exceed the capacity of any of the
electrical conductors and equipment in or otherwise serving the Premises or (b)
cause or result in any impairment or interference with Building systems,
annoyance or inconvenience to other tenants or the overloading of the risers,
wiring installations or feeders serving the Building. In order to prevent the
occurrence of any of the events described in the preceding sentence (and without
limiting the generality of the provisions of Article 5 hereof) and to avert
possible adverse effect upon the Building's electric service, Tenant shall not,
without Landlord's prior consent in each instance (which consent shall not be
unreasonably withheld), connect any fixtures, appliances or equipment (other
than a reasonable number of table or floor lamps, personal computers, monitors,
facsimile machines set forth in the plans and specifications approved by
Landlord in connection with the initial installation of the Tenant's
improvements) to the Building's electric distribution system or make any
Alteration or addition to the electric system of the Premises. Should Landlord
determine that increased capacity is required

                                      -30-
<PAGE>

for the entire building due to Tenant's request for additional electric
capacity, all additional risers or other equipment required shall be provided by
Landlord and the actual costs and expenses in connection therewith (prorated),
including, without limitation, those for filing and supervision, shall be paid
by Tenant to Landlord on demand as additional rent, without set-off or
deduction.

     11.4  Landlord has advised and Tenant acknowledges that Consolidated Edison
("Electric Service Provider") is presently the utility company selected by
Landlord to provide electricity service for the Building. Notwithstanding the
foregoing, Landlord shall have the right, at any time, and from time to time,
during the Term to either contract for service from a different company or
companies providing electricity ("Alternate Service Provider") or continue to
contract for service from the Electric Service Provider at rates that are
commercially reasonable in the then current marketplace.

         (a  Tenant shall cooperate with Landlord, the Electric Service
Provider, and any Alternate Service Provider at all times and, as reasonably
necessary, shall allow Landlord, Electric Service Provider, and any Alternate
Service Provider reasonable access to the Premises, including, but not limited
to Tenant's electric lines, feeders, risers, wiring, cables and any other
machinery or equipment within the Premises.

         (b  Landlord shall in no way be liable or responsible for any loss,
damage, or expense that Tenant may sustain or incur by reason of any change,
failure, interference, disruption, or defect in the supply or character of the
electric energy furnished to the Premises, or if the quantity or character of
the electric energy supplied by the Electric Service Provider or any Alternate
Service Provider is no longer available or suitable for Tenant's requirements,
and no such change, failure, defect, unavailability, or unsuitability shall
constitute an actual or constructive eviction, in whole or in part, or entitle
Tenant to any abatement or diminution of rent, or relieve Tenant from any of its
obligations under the Lease.

     11.5  Landlord shall have the right, in its sole discretion, to chose an
internet service provider ("ISP") for the Building at rates that are
commercially reasonable in the then current marketplace.  Tenant shall cooperate
with Landlord and the ISP at all times and, as reasonably necessary, shall allow
Landlord, the ISP reasonable access to the Premises, including, but not limited
to Tenant's electric lines, feeders, risers, wiring, cables and any other
machinery or equipment within the Premises. Landlord shall in no way be liable
or responsible for any loss, damage, or expense that Tenant may sustain or incur
by reason of any change, failure, interference, disruption, or defect in the
supply or character of internet service furnished to the Premises, or if the
quantity or character of the internet service supplied by the ISP or if such
internet service is no longer available or suitable for Tenant's requirements,
and no such change, failure, defect, unavailability, or unsuitability shall
constitute an actual or constructive eviction, in whole or in part, or entitle
Tenant to any abatement or diminution of rent, or relieve Tenant from any of its
obligations under the Lease. Alternatively, Tenant may utilize its own ISP
provided it first obtains the prior written consent of Landlord which consent
shall not be unreasonably withheld.

                                      -31-
<PAGE>

                                   ARTICLE 12

                        Adjacent Excavation -- Shoring--
                        --------------------------------

     If an excavation or other substructure work shall be made upon land
adjacent to the Premises, or shall be authorized to be made, Tenant shall afford
to the person causing or authorized to cause such excavation, license to enter
upon the Premises for the purpose of doing such work as shall be necessary to
preserve the wall of or the Building of which the Premises form a part from
injury or damage and to support the same by proper foundations without any claim
for damages or indemnity against Landlord, or diminution or abatement of rent.

                                   ARTICLE 13

                                  Condemnation
                                  ------------

     13.1  In the event that the whole of the Premises lawfully shall be
condemned or taken in any manner for any public or quasi-public use, this Lease
and the term and estate hereby granted shall cease and terminate as of the date
of vesting of title, as if that were the Expiration Date, and the fixed annual
rent and the additional rent payable pursuant to Article 3 of this Lease shall
be apportioned as of such date.

     13.2  In the event that only a part of the Premises shall be so condemned
or taken, then, effective as of the date of vesting of title, the fixed annual
rent and the additional rent payable pursuant to Article 3 hereunder shall be
abated in an amount thereof apportioned according to the area of the Premises so
condemned or taken. In the event that only a part of the Building or the Land
shall be so condemned or taken, then (a) Landlord (whether or not the Premises
be affected) may, at Landlord's option, terminate this Lease and the term and
estate hereby granted as of the date of such vesting of title by notifying
Tenant in writing of such termination within forty-five (45) days following the
date on which Landlord shall have received notice of vesting of title, or (b) if
such condemnation or taking shall be of a substantial part of the Premises or of
a substantial part of the means of access thereto, Tenant, at Tenant's option,
by delivery of notice in writing to Landlord within thirty (30) days following
the date on which Tenant shall have received notice of vesting of title, may
terminate this Lease and the term and estate hereby granted as of the date of
vesting of title, or (c) if neither Landlord nor Tenant elects to terminate this
Lease, as aforesaid, this Lease shall be and shall remain unaffected by such
condemnation or taking, except that the fixed annual rent and the additional
rent payable pursuant to Article 3 shall be abated to the extent hereinbefore
provided in this Article 14. In the event that only a part of the Premises shall
be so condemned or taken and this Lease and the term and estate hereby granted
with respect to the remaining portion of the Premises are not terminated as
hereinbefore provided, Landlord, with reasonable diligence and at its expense,
will restore the remaining portion of the Premises as nearly as practicable to
the same condition as it was in prior to such condemnation or taking.

     13.3  In the event of any condemnation or taking hereinbefore mentioned of
all or a part of the Building, Landlord shall be entitled to receive the entire
award in the condemnation proceeding, including any award made for the value of
the estate vested by this Lease in Tenant, and Tenant

                                      -32-
<PAGE>

hereby expressly assigns to Landlord any and all right, title and interest of
Tenant now or hereafter arising in or to any such award or any part thereof, and
Tenant shall be entitled to receive no part of such award. Tenant shall be
entitled to make a separate claim for the unamortized value of its trade
fixtures actually taken and for moving expenses so long as such claim will not
reduce the award payable to Landlord.

     13.4  If the temporary use or occupancy of all or any part of the Premises
shall be taken by condemnation or in any other manner for any public or quasi-
public use or purpose during the Term of this Lease, Tenant shall be entitled,
except as hereinafter set forth, to receive that portion of the award or payment
for such taking which represents compensation for the use and occupancy of the
Premises, for the taking of Tenant's property and for moving expenses, and
Landlord shall be entitled to receive that portion which represents
reimbursement for the cost of restoration of the Premises. This Lease shall be
and remain unaffected by such taking and Tenant shall continue responsible for
all of its obligations hereunder insofar as such obligations are not affected by
such taking and shall continue to pay in full the fixed annual rent and
additional rent due in accordance with the Lease. If the period of temporary use
or occupancy shall extend beyond the Expiration Date that part of the award
which represents compensation for the use and occupancy of the Premises (or a
part thereof) shall be divided between Landlord and Tenant so that Tenant shall
receive so much thereof as represents the period up to and including the
Expiration Date. All monies paid as, or as part of, an award for temporary use
and occupancy for a period beyond the date to which the fixed annual rent and
additional rent have been paid shall be received, held and applied by Landlord
as a trust fund for payment of the fixed annual rent and additional rent
becoming due hereunder.

     13.5  In the event of any taking of less than the whole of the Building
that does not result in a termination of this Lease, or in the event of a taking
for a temporary use or occupancy of all or any part of the Premises that does
not result in a termination of this Lease, Landlord, at its expense, and whether
or not any award or awards shall be sufficient for the purpose, shall proceed
with reasonable diligence to repair, alter and restore the remaining parts of
the Building and the Premises to substantially their former condition to the
extent that the same may be feasible and so as to constitute a tenantable
Building and Premises.

     13.6  In the event any part of the Premises be taken to effect compliance
with any law or requirement of public authority other than in the manner
hereinabove provided in this Article 13, then, (a) if such compliance is the
obligation of Tenant under this Lease, Tenant shall not be entitled to any
diminution or abatement of rent or other compensation from Landlord therefor,
but (b) if such compliance is the obligation of Landlord under this Lease, the
fixed annual rent payable under Article 1 shall be reduced and additional rent
payable under Article 3 shall be adjusted in the same manner as is provided in
Section 13.1 according to the reduction in rentable area of the Premises
resulting from such taking.

                                      -33-
<PAGE>

                                   ARTICLE 14

                          Access to Premises; Changes
                          ---------------------------

     14.1  Tenant shall permit Landlord (a) to erect, use and maintain pipes,
ducts and conduits in and through the Premises, provided the same are installed
adjacent to or boxed in a manner consistent with Tenant's decor or concealed
behind walls and ceilings of the Premises or in such manner as shall not
materially impair Tenant's use of the Premises, and (b) to use any air-
conditioning rooms, telephone equipment rooms, heating, ventilating, air-
conditioning, electrical and mechanical facilities and service closets
(collectively, the "Building Equipment") in the Premises. To the extent
practicable, Landlord shall install such pipes, ducts and conduits by methods
and at locations that will not materially interfere with or impair Tenant's
layout or use of the Premises. Landlord or its agents or designees shall have
the right to enter the Premises, at reasonable times during Business Hours on
Business Days and at other times, to examine such pipes, ducts, conduits and
Building Equipment or to make any repairs or alterations that Landlord may deem
necessary or reasonably desirable for the Building or that Landlord shall be
required to or shall have the right to make by the provisions of this Lease or
any other lease in the Building. Landlord shall be allowed to take all material
into and upon the Premises that may be required for the repairs or alterations
above mentioned as the same is required for such purpose, without the same
constituting an eviction of Tenant in whole or in part, and the rent reserved
shall in no way abate while said repairs or alterations are being made by reason
of loss or interruption of the business of Tenant because of the prosecution of
any such work. Landlord shall exercise reasonable diligence to minimize the
disturbance of Tenant's business operations but nothing contained herein shall
be deemed to require Landlord to perform the same on an overtime or premium pay
basis.

     14.2  Landlord reserves the right, without the same constituting an
eviction and without incurring liability to Tenant there for, to change the
arrangement and/or location of public entrances, passageways, doors, doorways,
corridors, elevators, stairways, toilets and other public parts of the Building;
provided, however, that Tenant shall continue to have access to the Building.

     14.3  Landlord may, at any time on reasonable prior notice, exhibit the
Premises to prospective tenants during the last twelve (12) months of the Term,
and Tenant is entitled to but is not required to be present during such
exhibition; provided, however, that in the event of a default by Tenant
hereunder, Landlord may exhibit the Premises to prospective tenants without
notice to tenant. Landlord shall also have the right to enter the Premises for
the purpose of exhibiting them to prospective purchasers or lessees of the
entire Building or to prospective mortgagees or to prospective assignees of any
such mortgages or to the holder of any mortgage on the Landlord's interest in
the property, its agents or designees and to the extent practicable shall
provide Tenant with prior written notice thereof.

     14.4  If Tenant shall not be present personally to open and to permit an
entry into the Premises at any time when for any reason an entry therein
urgently shall be reasonably necessary in case of fire or other emergency,
Landlord or Landlord's agents may enter the same forcibly without rendering
Landlord or such agents liable therefor (if during such entry Landlord or
Landlord's agents shall accord reasonable care to Tenant's property) and without
in any manner affecting the obligations and covenants of this Lease. If during
the last month of the  Term Tenant shall have

                                      -34-
<PAGE>

removed all or substantially all of Tenant's property therefrom, Landlord
immediately may enter, alter, renovate or redecorate the Premises without
limitation or abatement of rent and without incurring liability to Tenant for
any compensation and such act shall have no effect on this Lease or Tenant's
obligations hereunder.

                                   ARTICLE 15

                            Conditions of Limitation
                            ------------------------

     15.1  This Lease and the term and estate hereby granted are subject to the
limitation that whenever Tenant shall be unable to pay its debts generally as
they become due, or shall make an assignment of the property of Tenant for the
benefit of creditors, or shall consent to, or acquiesce in, the appointment of a
liquidator, receiver, trustee, or other custodian of itself or the whole or any
part of its properties or assets, or shall commence a voluntary case for relief
under the United States Bankruptcy Code or file a petition or take advantage of
any bankruptcy or insolvency act or applicable law of like import, or whenever
an involuntary case under the United States Bankruptcy Code shall be commenced
against Tenant or if a petition shall be filed against it seeking similar relief
under any bankruptcy or insolvency or other applicable law of like import, or
whenever a receiver, liquidator, trustee, or other custodian of Tenant or of or
for substantially all of the property of Tenant shall be appointed without
Tenant's consent or acquiescence, then, (a) at any time after receipt of notice
of the occurrence of any such event, or (b) if such event occurs without the
acquiescence of Tenant, at any time after the event continues for ten (10) days,
Landlord may give Tenant a notice of intention to end the Term of this Lease at
the expiration of five (5) days from the date of service of such notice of
intention, and upon the expiration of said five (5) day period, this Lease and
the term and estate hereby granted, whether or not the Term shall theretofore
have commenced, shall terminate with the same effect as if that day were the
Expiration Date, but Tenant shall remain liable for damages as provided in
Article 17.

     15.2   This Lease and the term and estate hereby granted are subject to
further limitation as follows:

            (a   whenever Tenant shall default in the payment of any installment
of fixed annual rent or in the payment of any additional rent on any day that
the same becomes due, and such default shall continue uncured for five days
after notice thereof to Tenant, or

            (b   whenever Tenant shall do or permit anything to be done, whether
by action or inaction, contrary to any of Tenant's obligations hereunder, and if
such situation shall continue and shall not be remedied by Tenant within ten
(10) days (within three days, in the case of Tenant's failure (i) to furnish any
certificate of insurance required under Articles 4 or 7 or (ii) to furnish any
instrument required under Articles 24 or 25 after Landlord shall have given to
Tenant a written notice specifying the same, or, in the case of a happening or
default that cannot with due diligence be cured within a period of 10 days and
the continuation of which for the period required for cure will not subject
Landlord to the risk of criminal liability (as more particularly described in
Article
                                      -35-
<PAGE>

7 hereof) or termination of any superior lease or foreclosure of any
superior mortgage, if Tenant shall not, (x) within said 10 day period advise
Landlord of Tenant's intention duly to institute all steps necessary to remedy
such situation, (y) duly institute within said 10 day period, and thereafter
diligently and continuously prosecute to completion all steps necessary to
remedy the same and (z) complete such remedy within such time after the date of
the giving of said notice by Landlord as shall reasonably be necessary, or

         (c   whenever any event shall occur or any contingency shall arise
whereby this Lease or the estate hereby granted or the unexpired balance of the
Term hereof, by operation of law or otherwise, devolves upon or pass to any
person, firm or corporation other than Tenant, except as expressly permitted by
Article 9, or

         (d   whenever Tenant shall abandon or vacate the Premises as set forth
in Article 37 hereof, or

         (e   whenever in case any other lease held by Tenant (or any person
which, directly or indirectly, controls, is controlled by, or is under common
control with, Tenant) from Landlord shall expire and terminate (whether or not
the  Term thereof shall then have commenced) as a result of the default of
Tenant thereunder or of the occurrence of an event as therein provided (other
than by expiration of the fixed term thereof or pursuant to a cancellation or
termination option therein contained), or

         (f   whenever Tenant shall default in the due keeping, observing or
performance of any covenant, agreement, provision or condition of Article 5
hereof on the part of Tenant to be kept, observed or performed and such default
shall continue and shall not be remedied by Tenant within 48 hours after
Landlord shall have given to Tenant written notice specifying the same;

then in any of said cases set forth in the foregoing subsections (a) through
(f), Landlord may give to Tenant a written notice of intention to end the Term
of this Lease at the expiration of three (3) days from the date of the service
of such written notice of intention to end the Term of this Lease, and upon the
expiration of said three (3) days this Lease and the term and estate hereby
granted, whether or not the Term shall theretofore have commenced, shall
terminate with the same effect as if that day were the Expiration Date, but
Tenant shall remain liable for damages as provided in Article 17.

     15.3   In the event Tenant shall default in the performance of any term of
this Lease to be performed by Tenant (other than the payment of fixed annual
rent) more than three times in any period of six months or, with respect to the
payment of fixed annual rent, more than two times in any period of 12 months,
then, notwithstanding that such defaults shall have each been cured within the
applicable grace period, if any, as provided above, any further similar default
shall, after written notice of the same, be deemed to be deliberate and Landlord
thereafter may serve the said ten (10) days' notice of termination upon Tenant
without affording to Tenant an opportunity to cure such default.

                                      -36-
<PAGE>

                                   ARTICLE 16

                        Re-Entry by Landlord; Injunction
                        --------------------------------

     16.1  If Tenant shall default in the payment of any installment of fixed
annual rent, or of any additional rent, on any date that the same becomes due,
and such default shall continue uncured for five days, or if this Lease shall
expire as in Article 15 provided, Landlord or Landlord's agents and employees
immediately or at any time thereafter may re-enter the Premises, or any part
thereof, either by summary dispossess proceedings or by any suitable action or
proceeding at law, or by force or otherwise, without being liable to indictment,
prosecution or damages therefrom, to the end that Landlord may have, hold and
enjoy the Premises again as and of its first estate and interest therein. The
word re-enter, as herein used, is not restricted to its technical legal meaning.
In the event of any termination of this Lease under the provisions of Article 15
or if Landlord shall re-enter the Premises under the provisions of this Article
16 or in the event of the termination of this Lease, or of re-entry, by or under
any summary dispossess or other proceeding or action or any provision of law by
reason of default hereunder on the part of Tenant, (a) Tenant thereupon shall
pay to Landlord the fixed annual rent and additional rent payable by Tenant to
Landlord up to the time of such termination of this Lease, or of such recovery
of possession of the Premises by Landlord, as the case may be, (b) Tenant shall
pay to Landlord all reasonable expenses, including reasonable court costs and
reasonable attorneys' fees and reasonable disbursements, incurred by Landlord in
recovering possession of the Premises and all costs and charges for the care of
the Premises while vacant and (c) Tenant also shall pay to Landlord damages as
provided in Article 17.

     16.2  In the event of a breach or threatened breach by Tenant of any of its
obligations under this Lease, Landlord also shall have the right of injunction.
The special remedies to which Landlord may resort hereunder are cumulative and
are not intended to be exclusive of any other remedies or means of redress to
which Landlord lawfully may be entitled at any time and Landlord may invoke any
remedy allowed at law or in equity as if specific remedies were not provided for
herein.

     16.3  If this Lease shall terminate under the provisions of Article 15, or
if Landlord shall re-enter the Premises under the provisions of this Article 16,
or in the event of the termination of this Lease, or of re-entry, by or under
any summary dispossess or other proceeding or action or any provision of law by
reason of default hereunder on the part of Tenant, Landlord shall be entitled to
retain all moneys, if any, paid by Tenant to Landlord, whether as advance rent,
security or otherwise, but such moneys shall be credited by Landlord against any
fixed annual rent or additional rent due from Tenant at the time of such
termination or re-entry or, at Landlord's option against any damages payable by
Tenant under Article 17 or pursuant to law.

     16.4  Tenant 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 for any cause, 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 or otherwise.

                                      -37-
<PAGE>

                                   ARTICLE 17

                                    Damages
                                    -------

     17.1  If this Lease is terminated under the provisions of Article 15, or if
Landlord shall re-enter the Premises under the provisions of Article 16, or in
the event of the termination of this Lease, or of re-entry, by or under any
summary dispossess or other proceeding or action or any provision of law by
reason of default hereunder on the part of Tenant, Tenant shall pay to Landlord
as damages, at the election of Landlord, either

         (a   a sum which at the time of such termination of this Lease or at
the time of any such re-entry by Landlord, as the case may be, represents the
then value of the excess, if any, of

             (i)  the aggregate of the fixed annual rent and the additional rent
     payable hereunder that would have been payable by Tenant (conclusively
     presuming the additional rent to be the same as was payable for the year
     immediately preceding such termination except that additional rent on
     account of increases in Taxes shall be presumed to increase at the average
     of the rates of increase thereof previously experienced by Landlord during
     the period (not to exceed 3 years) prior to such termination for the period
     commencing with such earlier termination of this Lease or the date of any
     such re-entry, as the case may be, and ending with the Expiration Date),
     had this Lease not so terminated or had Landlord not so re-entered the
     Premises, over

             (ii) the aggregate rental value of the Premises for the same
         period; or

         (b   sums equal to the aggregate of the fixed annual rent and the
additional rent (as above presumed) payable hereunder that would have been
payable by Tenant had this Lease not so terminated, or had Landlord not so re-
entered the Premises, payable upon the due dates therefor specified herein
following such termination or such re-entry and until the Expiration Date,
provided, however, that if Landlord shall re-let the Premises during said
period, Landlord shall credit Tenant with the net rents received by Landlord
from such re-letting, such net rents to be determined by first deducting from
the gross rents as and when received by Landlord from such reletting, the
reasonable expenses incurred or paid by Landlord in terminating this Lease or in
re-entering the Premises and in securing possession thereof, as well as the
reasonable expenses of reletting, including altering and preparing the Premises
for new tenants, reasonable brokers' commissions, reasonable attorneys' fees and
disbursements, and all reasonable other expenses properly chargeable against the
Premises and the rental thereof; it being understood that any such re-letting
may be for a period shorter or longer than the remaining term of this Lease and
that Landlord may grant concessions and free rent; but in no event shall Tenant
be entitled to receive any excess of such net rents over the sums payable by
Tenant to Landlord hereunder, or shall Tenant be entitled in any suit for the
collection of damages pursuant to this subsection to a credit in respect of any
net rents from a re-letting, except to the extent that such net rents actually
are received by Landlord. If the Premises or any part thereof should be re-let
in combination with other space, then proper apportionment on a square foot
basis shall be

                                      -38-
<PAGE>

made of the rent received from such re-letting and of the expenses of re-
letting. Landlord in no event shall be liable in any way whatsoever for failure
to re-let the Premises nor shall such failure affect Tenant's liability for
damages.

     17.2  If the Premises or any part thereof shall be re-let by Landlord for
the unexpired portion of the Term of this Lease, or any part thereof, before
presentation of proof of such damages to any court, commission or tribunal, the
amount of rent reserved upon such re-letting, prima facie, shall be the fair and
reasonable rental value for the Premises, or part thereof, so re-let during the
term of the re-letting.

     17.3  Suit or suits for the recovery of such damages, or any installments
thereof, may be brought by Landlord from time to time at its election, and
nothing contained herein shall be deemed to require Landlord to postpone suit
until the date when the term of this Lease would have expired if it had not been
so terminated under the provisions of Article 15, or under any provision of law,
or had Landlord not re-entered the Premises. Nothing herein contained shall be
construed to limit or to preclude recovery by Landlord against Tenant of any
sums or damages to which, in addition to the damages particularly provided
above, Landlord lawfully may be entitled by reason of any default hereunder on
the part of Tenant. Nothing herein contained shall be construed to limit or
prejudice the right of Landlord to prove for and obtain as liquidated damages by
reason of the termination of this Lease or re-entry of the Premises for the
default of Tenant under this Lease, an amount equal to the maximum allowed by
any statute or rule of law in effect at the time when such damages are to be
proved whether or not such amount be greater than, equal to, or less than any of
the sums referred to in Section 17.1.

                                   ARTICLE 18

                Landlord's Right to Perform Tenant's Obligations
                ------------------------------------------------

     If Tenant shall default in the observance or performance of any term or
covenant on Tenant's part to be observed or performed under or by virtue of any
of the terms or provisions in any Article of this Lease, (a) Landlord may, but
shall not be obligated to, remedy such default for the account of Tenant,
immediately and without notice in case of emergency, or in any other case only
provided that Tenant shall fail to remedy such default with all reasonable
dispatch after Landlord shall have notified Tenant in writing of such default
and the applicable grace period for curing such default shall have expired; and
(b) if Landlord makes any expenditures or incurs any obligations for the payment
of money in connection with such default (including, but not limited to,
reasonable attorneys' fees in instituting, prosecuting or defending any action
or proceeding), such sums paid or obligations incurred shall be deemed to be
additional rent hereunder and shall be paid by Tenant to Landlord within twenty
(20) days after return of a bill to Tenant therefor together with an amount
equal to 10% of Landlord's expenditure (to reimburse Landlord for its
administrative expenses) upon demand, as additional rent.

                                      -39-
<PAGE>

                                   ARTICLE 19

                                Quiet Enjoyment
                                ---------------

     Landlord covenants and agrees that, subject to the terms, obligations and
provisions of this Lease, if, and so long as, Tenant keeps and performs each and
every covenant, agreement, term, provision and condition herein contained on the
part or on behalf of Tenant to be kept or performed, then Tenant's rights under
this Lease shall not be disturbed, cut off or ended before the expiration of the
term of this Lease.

                                   ARTICLE 20

                             Services and Equipment
                             ----------------------

     20.1  So long as Tenant is not in default under any of the covenants of
this Lease, Landlord shall:

         (a   Provide twenty four hours per day/seven days a week nonexclusive
passenger elevator service to Tenant and freight elevator service on Business
Days during Business Hours.  During all times other than those indicated above,
Landlord shall provide Tenant with freight elevator service, provided Tenant
gives Landlord reasonable prior notice ("Overtime Freight Elevator Service").
Tenant shall pay Landlord the charges for Overtime Freight Elevator Service that
in an amount of ($50.00) per our as additional rent.  Tenant may after Business
Hours and not on Business days "lock-off" elevator access to the Premises.
Subject to the other applicable provisions of this lease, provide, on Business
Days during Business Hours, heat from October 15 through May 15 of each year
during the Term.  Tenant shall cause all of the windows in the Premises to be
kept closed and shall keep entirely unobstructed all the vents, intakes, outlets
and grilles whenever the air-conditioning or heating system is in operation and
shall comply with and observe all regulations and requirements prescribed by
Landlord.

         (b   Tenant, at its sole cost and expense, shall be responsible for
cleaning the Premises with a cleaning contractor approved by Landlord which
approval shall not be unreasonably withheld. In addition, Tenant shall be
responsible, at its own cost and expense, for the removal from the Premises and
the Building of any refuge and rubbish in accordance with the rules, regulations
and provisions of this Lease. Tenant's cleaning contractor and their employees
shall have access to the Premises after 6:00 p.m. and before 8:00 a.m. on
Business days, have nonexclusive use of the Building's freight elevator without
charge and shall have the right to use, without charge, all light, power and
water in the Premises reasonably required to clean the Premises as set forth
under this Section 20.

         (c   furnish hot and cold water for lavatory and drinking and office
cleaning purposes. If Tenant requires, uses or consumes water for any other
purposes or in unusual quantities (as determined by Landlord in its reasonable
discretion), Landlord may install a meter or meters or

                                      -40-
<PAGE>

other means to measure Tenant's water consumption, and Tenant shall reimburse
Landlord for the reasonable cost of the meter or meters and the installation
thereof, and shall pay for the maintenance of said meter equipment and/or shall
pay Landlord's reasonable costs of other reasonable means of measuring such
water consumption by Tenant. In the event such a meter is installed by Landlord,
Tenant shall reimburse Landlord for the cost of all water consumed in excess of
what is normal for commercial operations similar to Tenant, including sewer
rents, as measured by said meter or meters or as otherwise measured, and the
cost to heat such water.

           (d   to the extent permitted by law and provided Tenant makes all
necessary Alterations so that such use is in compliance with all Legal
Requirements and Rules and Regulations, Tenant's employees shall be permitted to
utilize the stairwell between the 7/th/ and 8/th/ floors of the Premises to get
to and from the 7/th/ and 8/th/ floors of the Premises.

     20.2  Landlord reserves the right, without any liability whatsoever and
without abatement of fixed annual rent or additional rent, to stop the heating,
chilled water, elevator, plumbing, sanitary, electric and other systems when
necessary by reason of accident or emergency or for repairs, alterations,
replacements or improvements, provided that except in case of emergency,
Landlord will notify Tenant in advance, if possible, of any such stoppage and,
if ascertainable, its estimated duration, and will proceed diligently with the
work necessary to resume such service as promptly as possible and in a manner so
as to minimize interference with Tenant's use and enjoyment of the Premises.
Landlord shall not be liable in any way to Tenant for any failure of the
heating, chilled water, elevator, plumbing, sanitary, electric and other systems
by reason of any failure or defect in the supply or character of electric energy
furnished to the Building or the Premises by the public utility serving the
Building except for the negligence or willful misconduct of Landlord.

     20.3  Landlord, at Tenant's request, shall maintain listings on the
Building directory the name of Tenant, Tenant's officers, employees, permitted
assignees and permitted subtenants provided, however, that the aggregate number
of names so listed shall not exceed ten (10). The reasonable charge of Landlord
for any changes in such listings requested by Tenant shall be paid by Tenant to
Landlord on demand. Landlord, at Tenant's request and subject to Landlord's
reasonable fee, shall place Tenant's name on other signs in the Building which
contain the names of any of the other tenants in the Building. The Building may
be designated and known by any name or address Landlord may choose and such
designated name or address may be changed from time to time in Landlord's sole
discretion; provided, however, that for so long as the original Tenant, its
Affiliate or a successor corporation (as such terms are defined and described in
this Lease) remain in actual occupancy of the 7/th/ and 8/th/ floors of the
Premises, Landlord represents that it shall not "name" the building for another
internet consulting company. Tenant acknowledges that Landlord has permitted
another tenant in the Building to hang a banner/flag containing the tenant's
name and logo design on the outside facade of the building below the sixth floor
of the Building. Tenant, subject to Landlord's prior written consent, which
consent shall not be unreasonably withheld, and provided further it is done in
accordance with Legal Requirements, may stencil the Tenant's name or logo into
the glass windows on the 7/th/ and 8/th/ floors of the Building contained within
in the Premises, in a tasteful manner and in keeping with the character and
quality of the Building.

                                      -41-
<PAGE>

     20.4  Landlord, at its expense, shall clean and maintain the common areas
of the Building (including, the lobby, hallways and elevators). Landlord shall
clean the exterior windows of the Building within the Premises once per calendar
year during the term of the Lease.

     20.5  Landlord shall not be required to furnish any other services, except
as otherwise provided in this Lease.

                                  ARTICLE 21

                              Hazardous Materials
                              -------------------

     21.1  Tenant shall not, without the prior written consent of Landlord,
cause or permit, knowingly any Hazardous Material (hereinafter defined) to be
brought or remain upon, kept or used in or about the Premises or the Building.
As used in this Lease, "Hazardous Material(s)" shall mean any hazardous, toxic
or radioactive substance, material, matter or waste, including, but not limited
to, asbestos and lead paint which is or becomes regulated by any federal, state
or local law, rule regulation, code, ordinance or any other governmental
restriction or requirement. However, "Hazardous Materials" shall not include
substances which are used in the ordinary course of a business similar to
Tenant's as permitted pursuant to Article 5 of this Lease, provided, however,
that such substances are used, handled, transported or stored in strict
compliance with any applicable Legal Requirement. If such substances are not so
used, handled, transported or stored then they shall be deemed "Hazardous
Materials" for purposes of this Lease. Should Landlord consent in writing to
Tenant bringing, using or storing any Hazardous Material in or upon the Premises
or the Building, Tenant shall strictly obey and adhere to any and all Legal
Requirements which in any way regulates, governs or impacts Tenant's possession,
use, storage or disposal of said Hazardous Material. Upon Landlord's written
request, prior to the Commencement Date of this Lease, and on January 1 of each
year thereafter, Tenant shall disclose in writing to Landlord the names and
amounts of all Hazardous Material which Tenant is then currently or is intending
to bring, use, or store in or upon the Premises or the Building, or which Tenant
has in the past brought, used or stored in or upon the Premises or the Building.

     21.2  In addition to, and in no way limiting Tenant's duties and
obligations as set forth in this Lease, should Tenant breach any of its duties
and obligations as set forth in this Lease or if the presence of any Hazardous
Material in or upon the Premises or the Building, that Tenant causes or permits
knowingly to brought upon, used, remained upon or kept at the Premises
(excluding those Hazardous Materials that were present in the Premises prior to
Tenant's occupancy and those Hazardous Materials brought upon the Premises by
Landlord after Tenant's occupancy) results in contamination of the Premises, the
Building, any Land or the Building, the atmosphere, or any water or waterway
(including groundwater), or if contamination of the Premises, or the Building by
any Hazardous Material otherwise occurs for which Tenant is otherwise legally
liable to Landlord for damage resulting therefrom, Tenant shall indemnify, save
harmless, and, at Landlord's option and with attorneys approved in writing by
Landlord, defend Landlord and its agents, employees, partners,

                                      -42-
<PAGE>

officers, directors, and mortgagees, if any, from any and all claims, demands,
damages, expenses, fees, costs, fines, penalties, suits, proceedings, actions,
causes of action, and losses of any and every kind and nature, including,
without limitation, diminution in value of the Premises or the Building, damages
for the loss or restriction on use of the rentable or usable space or of any
amenity of the Premises or the Building, damages arising from any adverse impact
on marketing space in the Building, and sums paid in settlement of claims and
for attorney's fees, consultant fees and expert fees, which may arise during or
after the Term or any extension thereof as a result of such contamination. This
includes, without limitation, costs and expenses incurred in connection with any
investigation of site conditions or any cleanup, remedial, removal or
restoration work required by any federal, state or local governmental agency or
political subdivision because of Hazardous Material present on or about the
Premises (excluding those Hazardous Materials that were present in the Premises
prior to Tenant's occupancy and those Hazardous Materials brought upon the
Premises by Landlord after Tenant's occupancy, that Tenant causes or permits
knowingly to be brought upon, used, remained upon or kept at the Premises) or
because of the presence of Hazardous Material anywhere else which came or
otherwise emanated from Tenant or the Premises (excluding those Hazardous
Materials that were present in the Premises prior to Tenant's occupancy and
those Hazardous Materials brought upon the Premises by Landlord after Tenant's
occupancy, that Tenant causes or permits knowingly to be brought upon, used,
remained upon or kept at the Premises). Without limiting the foregoing, if the
presence of any Hazardous Material on or about the Premises, or the Building
caused or permitted by Tenant results in any contamination of the Premises or
the Building, Tenant shall, at its sole expense, promptly take all actions as
are necessary to return the Premises and the Building to the condition existing
prior to the introduction or any such Hazardous Material to the Premises and the
Building; provided, however, that Landlord's approval of such actions shall
first be obtained.

     21.3  Landlord represents that it shall use its best efforts to ensure that
this Article 21 shall be included in all other tenants' leases in the Building.

                                   ARTICLE 22

                          Invalidity of Any Provision
                          ---------------------------

     If any term, covenant, condition or provision of this Lease or the
application thereof to any circumstance or to any person, firm or corporation
shall be invalid or unenforceable to any extent, the remaining terms, covenants,
conditions and provisions of this Lease or the application thereof to any
circumstances or to any person, firm or corporation other than those as to which
any term, covenant, condition or provision is held invalid or unenforceable,
shall not be affected thereby and each remaining term, covenant, condition and
provision of this Lease shall be valid and shall be enforceable to the fullest
extent permitted by law.

                                      -43-
<PAGE>

                                   ARTICLE 23

                                   Brokerage
                                   ---------

     Landlord and Tenant covenant, represent and warrant that they have had no
dealings or negotiations with any broker or agent other than Broker in
connection with the consummation of this Lease. Tenant and Landlord covenant and
agree to pay, hold harmless and indemnify each other from and against any and
all cost, expense (including reasonable attorneys' fees) and liability in
connection with any compensation, commissions or charges claimed by any broker
or agent, other than the Broker, with respect to this Lease or the negotiation
thereof. Landlord agrees to pay the Broker a commission in accordance with the
terms of a separate agreement between the respective parties. The provisions of
this Article shall survive the expiration or sooner termination of this Lease.

                                   ARTICLE 24

                                 Subordination
                                 -------------

     24.1  This Lease shall not be subject and subordinate to all present and
future ground or underlying leases and to all mortgages, options, and building
loan agreements that may now or hereafter affect such leases or the real
property of which the Premises are a part and to all renewals, modifications,
consolidations, replacements and extensions of any such ground or underlying
leases, options, building loan agreements and mortgages unless Landlord provides
Tenant with a subordination non-disturbance and attornment agreement in a form
reasonably satisfactory to Landlord and Landlord's mortgagee. Landlord
represents that as of the Commencement Date there are no mortgages against the
Building. In confirmation of such subordination, Tenant shall execute and
deliver promptly at its own cost and expense any instrument, in recordable form
if required, that Landlord, the lessor of the ground or underlying lease or the
holder of any such mortgage or any of their respective successors in interest
may request to evidence such subordination, and Tenant shall provide such
instrument to Landlord with five (5) days of such request.

     24.2  In the event of a termination of any ground or underlying lease, or
if the interests of Landlord under this Lease are transferred by reason of, or
assigned in lieu of, foreclosure or other proceedings for enforcement of any
mortgage, or if the holder of any mortgage acquires a lease in substitution
therefor, then Tenant under this Lease, at the option to be exercised in writing
by the lessor under such ground or underlying lease or such mortgagee or
purchaser, assignee or lessee, as the case may be, either (a) will attorn to it
and will perform for its benefit all the terms, covenants and conditions of this
Lease on Tenant's part to be performed with the same force and effect as if said
lessor, such mortgagee or purchaser, assignee or lessee, were the landlord
originally named in this Lease, or (b) will enter into a new lease with said
lessor or such mortgagee or purchaser, assignee or lessee, as landlord, for the
remaining term of this Lease and otherwise on the same terms and conditions and
with the same options, if any, then remaining. The foregoing provisions of
clause (a) of this Section 24.2 shall enure to the benefit of such lessor,
mortgagee, purchaser, assignee or lessee, shall be self-operative upon the
exercise of such option, and no further instrument shall be required to give
effect to said provisions. Tenant, however, within five (5) days of demand of
any such lessor, mortgagee, purchaser, assignee or lessee, shall execute, from
time to time, instruments

                                      -44-
<PAGE>

in confirmation of the foregoing provisions of this Section 24.2, satisfactory
to any such lessor, mortgagee, purchaser, assignee or lessee, acknowledging such
attornment and setting forth the terms and conditions of its tenancy. Landlord
shall notify Tenant within a reasonable period of time after such event occurs
of a change in mortgagee, owner or transferee.

     24.3  Anything herein contained to the contrary notwithstanding, under no
circumstances shall any lessor under any ground lease or mortgagee or purchaser,
assignee or lessee, as the case may be, whether or not it shall have succeeded
to the interests of the landlord under this Lease, be

           (a) liable for any act, omission or default of any prior landlord or
for the return of any security deposit or part thereof not actually received by
such lessor, mortgagee, purchaser, assignee, or lessee, as the case may be; or

           (b) subject to any offsets, claims or defenses that Tenant might have
against any prior landlord; or

           (c) bound by any rent or additional rent that Tenant might have paid
to any prior landlord for more than one month in advance or for more than three
months in advance where such rent payments are payable at intervals of more than
one month (other than payments for Tenant's Tax Payment which shall be paid in
accordance with the terms and conditions of Article 3 of this Lease); or

           (d) bound by any modification, amendment or abridgment of this Lease,
or any cancellation or surrender of the same, made without its prior written
approval.

     24.4  If, in connection with the financing of the Land and/or the Building,
the holder or prospective holder of any mortgage shall request reasonable
modifications in this Lease as a condition of approval thereof, Tenant will not
unreasonably withhold, delay or defer making such modifications.

                                  ARTICLE 25

                             Certificate of Tenant
                             ---------------------

     25.1  Tenant, without charge, at any time and from time to time, within
five (5) days after request by Landlord, shall deliver a written instrument to
Landlord or any other person, firm or corporation specified by Landlord, duly
executed and acknowledged, certifying:

           (a) that this Lease is unmodified and in full force and effect or, if
there has been any modification, that the same is in full force and effect as
modified and stating any such modification, that there is no existing basis to
cancel or terminate this Lease, and to the best of Tenant's knowledge Landlord
is not in default thereunder;

                                      -45-
<PAGE>

           (b) whether or not the Term of this Lease has commenced and rent
become payable thereunder, and whether Tenant is in possession of all of the
Premises except for such portions of the Premises that have been sublet or being
held for sublet pursuant to the provisions of this Lease and whether Landlord
substantially has completed the Landlord's Work;

           (c) whether or not there are then existing any defenses or offsets
that are not claims under paragraph (v) of this Section 25.1 against the
enforcement of any of the agreements, terms, covenants, or conditions of this
Lease and any modification thereof upon the part of Tenant to be performed or
complied with, and, if so, specifying the same;

           (d) the amount of the fixed annual rent payable under this Lease and
the dates to which the fixed annual rent and additional rent and other charges
hereunder have been paid;

           (e) whether or not Tenant has made any claim against Landlord under
this Lease and, if so, the nature and the dollar amount, if any, of such claim.

     25.2  In the event of any act or omission by Landlord, Tenant will not
exercise any right to terminate this Lease or to remedy the default and deduct
the cost thereof from rent due hereunder until Tenant shall have given written
notice of such act or omission to the ground lessor and to the holder of any
mortgage on the fee or the ground lease who shall have furnished such lessor's
or holder's last address to Tenant and until thirty (30) days for remedying such
act or omission shall have elapsed following the giving of such notices, during
which time such lessor or holder shall have the right, but shall not be
obligated, to remedy or cause to be remedied such act or omission. Tenant shall
not exercise any right pursuant to this Section 25.2 if the holder of any
mortgage or such aforesaid lessor commences to cure such aforesaid act or
omission within thirty (30) days and diligently prosecutes such cure thereafter.

     25.3  At Landlord's request, Tenant shall deliver promptly to Landlord and
to the holder of any mortgage on the fee or ground lease and the lessor under
any ground or underlying lease, after the occurrence of the Commencement Date, a
letter signed by Tenant and acknowledged, in substantially the form annexed
hereto as Schedule C.

                                   ARTICLE 26

                               Legal Proceedings;
                     Waiver of Jury Trial; Attorneys' Fees
                     -------------------------------------

     26.1  Landlord and Tenant hereby waive trial by jury in any action,
proceeding or counterclaim brought by either of the parties hereto against the
other on any matters whatsoever arising out of or in any way connected with this
Lease, the relationship of Landlord and Tenant, Tenant's use or occupancy of the
Premises, and/or any other claims (except claims for personal injury or property
damage), and any emergency statutory or any other statutory remedy. If Landlord
commences any summary proceeding, Tenant shall not interpose and hereby waives
the right to interpose any counterclaim of whatever nature or description in any
such proceeding. Tenant shall

                                      -46-
<PAGE>

reimburse Landlord, on demand, for all costs and expenses (including reasonable
attorneys' fees and disbursements and court costs, whether in connection with an
action or proceeding commenced by Landlord, by Tenant, by a third party or
otherwise) incurred by Landlord in connection with (a) enforcing Tenant's
obligations under this Lease, (b) the termination of this Lease and the eviction
of Tenant through summary or other proceedings or for any other relief against
Tenant, (c) recovering any sums due under this Lease or any damages for Tenant's
breach of the terms of this Lease, (d) determining the respective rights and
obligations of the parties to this Lease, including but not limited to, by
declaratory relief, (e) the appearance by Landlord, or any partner, employee,
agent or servant of Landlord, as a witness in any proceeding involving the
Premises, (f) the defense of any claim against Landlord or any partner,
employee, agent or servant of Landlord arising under this Lease, whether brought
by Tenant or a third party in which the claimant does not obtain a final,
unappealable judgment of all such claimant's allegations, (g) any amendment,
modification or change in any of the terms of this Lease requested by Tenant or
any renewal or extension of this Lease requested by Tenant, and any request or
negotiations pertaining thereto, regardless of whether such amendment,
modification, change, renewal or extension is actually executed, and (h) as
otherwise provided in this Lease. All such amounts shall be deemed to be
additional rent, but shall be collectible whether incurred before or after the
expiration or termination of this Lease.

     26.2  Tenant hereby agrees that any legal proceeding with respect to the
Lease may be brought in the courts of the State of New York or in the United
States District Court for the District in which the Building is located, as
Landlord may elect. Tenant hereby accepts with regard to any such legal
proceeding, for itself and in respect of its property, generally and
unconditionally, the jurisdiction of such courts. Nothing in this Article shall
affect Landlord's rights to commence legal proceedings or otherwise proceed
against Tenant in New York City or in any other jurisdiction in which assets of
Tenant are located or to serve process in any other manner permitted by
applicable law. Tenant further agrees that final judgment in any such legal
proceeding shall be conclusive and, to the extent permitted by applicable law,
may be enforced in any other jurisdiction within or outside the United States of
America by suit on the judgment, a certified or exemplified copy of which shall
be conclusive evidence of the fact and of the amount of Tenant's indebtedness.

                                   ARTICLE 27

                             Surrender of Premises
                             ---------------------

     27.1  Upon the expiration or other termination of the Term of this Lease,
Tenant shall quit and surrender the Premises to Landlord, broom clean, in good
order and condition, ordinary wear and tear and damage by fire, the elements or
other casualty excepted, and Tenant shall remove all of its personal property as
herein provided. Tenant's obligation to observe or perform the covenants in this
Article 28 shall survive the expiration or other termination of the Term of this
Lease.

     27.2  Tenant acknowledges that possession of the Premises must be
surrendered to Landlord at the expiration or sooner termination of the Term of
this Lease. The parties recognize and agree that the damage to Landlord
resulting from any failure by Tenant timely to surrender possession of

                                      -47-
<PAGE>

the Premises as aforesaid will be extremely substantial, will exceed the amount
of the monthly rent and additional rent theretofore payable hereunder, and will
be impossible to accurately measure. Tenant therefore agrees that if possession
of the Premises is not surrendered to Landlord within 24 hours after the date of
the expiration or sooner termination of the Term of this Lease, then,
notwithstanding anything to the contrary contained in this Lease, Tenant shall
pay to Landlord for each month and for each portion of any month during which
Tenant holds over in the Premises after the expiration or sooner termination of
the Term of this Lease, rent at the greater of (a) a rate equal to two times the
aggregate of that portion of the fixed annual rent and additional rent that was
payable under this Lease for the last month of the Term hereof, or (b) the then
market rent for the Premises, provided, however, that in no event shall Landlord
be entitled to receive an amount in excess of the maximum amount permitted by
Legal Requirements. Nothing herein contained shall be deemed to permit Tenant to
retain possession of the Premises after the expiration or sooner termination of
the Term of this Lease. The provisions of this Section 27.2 shall survive the
expiration or other termination of the Term of this Lease.

                                   ARTICLE 28

                             Rules and Regulations
                             ---------------------

     28.1  Tenant and Tenant's servants, employees and agents shall observe
faithfully and comply strictly with the Rules and Regulations set forth in
Schedule D and the Construction Rules and Regulations set forth in Schedule E
annexed hereto and made part hereof entitled "Rules and Regulations" and
"Construction Rules and Regulations" and such other and further reasonable Rules
and Regulations and Construction Rules and Regulations as Landlord or Landlord's
agents may adopt from time to time. In the event of any conflict or
inconsistency between the provisions of this Lease and of any of the Rules and
Regulations or Construction Rules and Regulations as originally or as hereafter
adopted, the provisions of this Lease shall control. Reasonable written notice
of any additional Rules and Regulations or Construction Rules and Regulations
shall be given to Tenant. Landlord shall not enforce the Rules and Regulations
and the Construction Rules and Regulations against Tenant in a discriminatory
manner.

     28.2  Nothing in this Lease contained shall be construed to impose upon
Landlord any duty or obligation to enforce the Rules and Regulations or the
Construction Rules and Regulations or the terms, covenants or conditions in any
other lease, against any other tenant of the Building, and Landlord shall not be
liable to Tenant for violation of the same by any other tenant, its servants,
employees, agents, visitors or licensees.

                                   ARTICLE 29

                             Consents and Approvals
                             ----------------------

     Wherever in this Lease Landlord's consent or approval is required, if
Landlord shall delay or refuse such consent or approval, Tenant in no event
shall be entitled to make, nor shall Tenant

                                      -48-
<PAGE>

make, any claim, and Tenant hereby waives any claim, for money damages (nor
shall Tenant claim any money damages by way of set-off, counterclaim or defense)
based upon any claim or assertion by Tenant that Landlord unreasonably withheld
or unreasonably delayed its consent or approval. Tenant's sole remedy shall be
an action or proceeding to enforce any such provision, for specific performance,
injunction or declaratory judgment.

                                  ARTICLE 30

                                    Notices
                                    -------

     Any notice, demand, consent, approval, disapproval, or statement
(collectively, "Notices") from Landlord to Tenant or from Tenant to Landlord
shall be in writing and shall be deemed duly given (a) if mailed by registered
or certified mail, postage prepaid, return receipt requested, (b) if delivered
by recognized national overnight delivery service with receipt acknowledged, or
(c) only in the case of Notices that are Escalation Statements or bills for
rent, if mailed by first class mail, postage prepaid, to the address(es) for
Notices set forth in this Article 31. Notices to Tenant shall be sent to Tenant
at the Premises and to One Main Street, Cambridge, Massachusetts, 02142 with a
copy of default notices only to Shearman and Sterling, Attn: Real Estate
Notices: Chris M. Smith, Esq. 599 Lexington Avenue, New York, New York 10022.
Notices to Landlord shall be sent (i) to the address of Landlord set forth on
page 1 of this Lease or (ii) to such other address as Landlord shall have last
designated by notice in writing to Tenant, with copies to Belkin Burden Wenig &
Goldman, LLP attention: Daniel T. Altman, Esq. Notice shall be deemed given on
the third business day after depositing same in an official depository of the
United States Postal Service (or successor organization) or, if given by
overnight delivery, upon delivery to Landlord or Tenant, as the case may be.

                                   ARTICLE 31

                                   No Waiver
                                   ---------

     No agreement to accept a surrender of this Lease shall be valid unless in
writing signed by Landlord. No employee of Landlord or of Landlord's agents
shall have any power to accept the keys to the Premises prior to the termination
of this Lease. The delivery of keys to any employee of Landlord or of Landlord's
agent shall not operate as a termination of this Lease or a surrender of the
Premises. If Tenant at any time desires to have Landlord sublet the Premises for
Tenant's account, Landlord or Landlord's agents are authorized to receive said
keys for such purpose without releasing Tenant from any of the obligations under
this Lease. The failure of Landlord to seek redress for violation of, or to
insist upon the strict performance of, any covenant or condition of this Lease
or any of the Rules and Regulations set forth herein, or hereafter adopted by
Landlord, shall not prevent a subsequent act, which would have originally
constituted a violation, from having all the force and effect of an original
violation. The receipt by Landlord of rent with knowledge of the breach of any
covenant of this Lease shall not be deemed a waiver of such breach. The failure
of Landlord to enforce any of the Rules and Regulations set forth herein, or
hereafter adopted, against Tenant and/or

                                      -49-
<PAGE>

any other tenant in the Building shall not be deemed a waiver of any such Rules
and Regulations. No provision of this Lease shall be deemed to have been waived
by Landlord, unless such waiver be in writing signed by Landlord. No payment by
Tenant or receipt by Landlord of a lesser amount than the monthly rent herein
stipulated shall be deemed to be other than on the account of the earliest
stipulated rent, nor shall any endorsement or statement on any check or any
letter accompanying any check or payment of rent be deemed an accord and
satisfaction, and Landlord may accept such check or payment without prejudice to
Landlord's right to recover the balance of such rent or pursue any other remedy
in this Lease provided.

                                   ARTICLE 32

                              Inability to Perform
                              --------------------

     If, by reason of (1) strike, (2) labor troubles, (3) governmental
preemption in connection with a national emergency, (4) any rule, order or
regulation of any governmental agency, (5) conditions of supply or demand which
are affected by war or other national, state or municipal emergency, or an act
of god (each, a "Force Majeure Event"), Landlord (i) shall be unable to provide
the services it is obligated to provide Tenant in accordance with Article 21 of
this Lease, (ii) Tenant is unable to use or occupy the entire Premises, (iii)
Tenant does not use or occupy any portion of the Premises and (iv) Landlord is
unable to restore and has not commenced the restoration of the services it is
obligated to provide Tenant in accordance with Article 21 of this Lease after
the tenth (10th) business day after the Force Majeure Event occurs, Tenant's
obligation to pay fixed annual rent hereunder shall be abated beginning on the
eleventh (11th) business day after the Force Majeure Event occurs and shall end
on the date the services Landlord is obligated to provide Tenant in accordance
with Article 21 of this Lease are restored (Tenant shall continue to be
obligated to pay fixed annual rent through the tenth (10th) business day after
the Force Majeure Event occurs), provided further, however, that as soon as
Tenant shall learn of the happening of the Force Majeure Event, Tenant shall
promptly notify Landlord of such event and, if ascertainable, its estimated
duration. Except as otherwise provided in this Article 32, this Lease and the
obligation of Tenant to pay rent hereunder and to perform all of the other
covenants and agreements hereunder on the part of Tenant to be performed shall
in no way be affected, impaired or excused because Landlord is unable to fulfill
any of its obligations under this Lease or to supply or is delayed in supplying
any service expressly or impliedly to be supplied or is unable to make, or is
delayed in making any repair, additions, alterations or decorations or is unable
to supply or is delayed in supplying any equipment or fixtures if Landlord is
prevented or delayed from so doing by reason of a Force Majeure Event.

                                   ARTICLE 33

                               Entire Agreement;
                    No Representations; No Oral Modification
                    ----------------------------------------

     33.1  This Lease and the Schedules attached hereto set forth all of the
covenants, promises, assurances, agreements, representations, conditions,
warranties, statements and understandings

                                      -50-
<PAGE>

(collectively, the "Representations") between Landlord and Tenant concerning the
Premises and the Building, and there are no Representations, either oral or
written, between Landlord and Tenant other than those set forth in this Lease.

     33.2  This Lease supersedes and revokes all previous negotiations,
arrangements, letters of intent, offers to lease, lease proposals, brochures,
Representations, and information conveyed, whether oral or in writing, between
Landlord and Tenant or their respective representatives or any other person
purporting to represent Landlord or Tenant. Tenant acknowledges that it has not
been induced to enter into this Lease by any Representations not set forth in
this Lease, it has not relied on any such Representation, no such
Representations shall be used in the interpretation or construction of the
Lease, and Landlord shall have no liability for any consequences arising as a
result of any such Representations.

     33.3  Except as otherwise provided in this Lease, no subsequent alteration,
amendment, change or addition to this Lease shall be binding upon Landlord or
Tenant unless in writing and signed by the party against whom enforcement of the
alteration, amendment, change or addition is sought.

                                  ARTICLE 34

                                   Security
                                   --------

     34.1  Simultaneous with the execution of this Lease, Tenant shall pay cash
in the amount of eight-hundred twenty-five thousand dollars ($825,000.00) or
deliver to Landlord a clean, unconditional, irrevocable standby Letter of Credit
(the "LC") having a one (1) year term, automatically renewable through and
including the third anniversary after the Commencement Date, naming Landlord as
beneficiary, in a form and substance reasonably satisfactory to Landlord,
initially in an amount equal to eight-hundred twenty-five thousand dollars
($825,000.00) as and for the security deposit (the "Security Deposit") for the
faithful performance and observance by Tenant of the terms, provisions,
covenants and conditions of this Lease including the terms and conditions of the
Work Letter annexed as Exhibit A. Provided that Tenant is not in default in
respect of any of the terms, provisions, covenants and conditions of this Lease
beyond applicable notice and grace periods, including, but not limited to, the
provisions of the Work Letter annexed as Exhibit A, the LC may be replaced by
Tenant on the third anniversary of the 7/th/ Floor Rent Commencement Date with
an amendment reducing the amount of the LC to four-hundred fifty-thousand seven-
hundred and forty-nine dollars and eighty-eight cents ($450,749.88) representing
six (6) months of the Fixed Annual Rent on the third anniversary of the 7/th/
Floor Rent Commencement Date. Landlord shall return the LC to Tenant on the
third anniversary of the 7/th/ Floor Rent Commencement Date. If Tenant defaults
in respect of any of the terms, provisions, covenants and conditions of this
Lease beyond applicable notice and grace periods, including, but not limited to,
the payment of fixed annual rent and additional rent, Landlord may use, apply or
retain the whole or any part of the Security Deposit to the extent required for
the payment of any fixed annual rent and additional rent or any other sum as to
which Tenant is in default or for any sum that Tenant is obligated to pay

                                      -51-
<PAGE>

Landlord or that Landlord may expend or may be required to expend by reason of
Tenant's default in respect of any of the terms, provisions, covenants and
conditions of this Lease beyond any applicable notice and grace period,
including but not limited to any damages payable by Tenant pursuant to Article
17 hereof. To the extent that Landlord, during the Term, so uses, applies, or
retains all or any part of the Security Deposit, tenant, on demand, shall pay to
Landlord as additional rent a sum sufficient to restore the Security Deposit to
the amount then required to be deposited. If Tenant shall comply fully and
faithfully with all of the terms, provisions, covenants and conditions of this
Lease, the Security Deposit shall be returned to Tenant within a reasonable
number of days after the date fixed as the end of the Lease and after delivery
of possession of the Premises to Landlord.

     34.2  In the event of a sale of the Land and the Building or the leasing or
transfer of the Building, Landlord shall have the right to transfer the Security
Deposit to the vendee or lessee or transferee and Landlord thereupon shall be
released by Tenant from all liability for the return of such Security Deposit
upon the transfer of the Security Deposit to the new landlord. Tenant shall look
solely to the new landlord for the return of the Security Deposit. The
provisions hereof shall apply to every transfer or assignment made of the
Security Deposit to a new landlord.

     34.3  Tenant covenants that it will not assign or encumber or attempt to
assign or encumber the money deposited as the Security Deposit under this Lease
and that neither Landlord nor its successors or assigns shall be bound by any
such assignment, encumbrance, attempted assignment or attempted encumbrance. In
the event that any bankruptcy, insolvency, reorganization or other debtor-
creditor proceedings shall be instituted by or against Tenant, its successors or
assigns, or any guarantor of Tenant hereunder, the Security Deposit shall be
deemed to be applied to the payment of the fixed annual rent and for additional
rent due Landlord for periods prior to the institution of such proceedings.

     34.4  Landlord shall deposit the Security Deposit into an interest-bearing
account at a banking organization selected by Landlord. All interest and/or
dividends, if any, accruing on the Security Deposit, less a 1% per annum charge
for administrative expense, shall be added to, held and included within the term
Security Deposit and, provided that Tenant is not in default in the performance
of the terms, provisions, covenants and conditions of this Lease, shall accrue
to the account of Tenant. Landlord shall not be required to credit Tenant with
any interest for any period during which Landlord does not receive interest on
the Security Deposit.

                                   ARTICLE 35

                              Continuous Operation
                              --------------------

     35.1  Tenant acknowledges that its continuous operation at the Premises by
the regular conduct of its business therein is of the utmost importance to
Landlord in the renewal of other leases in the Building, in the renting of
vacant space in the Building, and in the maintenance of the character and
quality of the Building. Tenant therefore covenants and agrees that it will with
due

                                      -52-
<PAGE>

dispatch and diligence promptly open for business in the Premises and thereafter
continuously, actively and diligently operate such business. Tenant acknowledges
that Landlord is executing this Lease in reliance upon these covenants, which
are a material inducement to Landlord to execute this Lease. Tenant further
agrees that if it fails to so continuously conduct its business in the Premises
a period of one-hundred and twenty (120) consecutive days at any time during the
Term of this Lease, without prior written consent of Landlord, then such failure
shall be deemed default of a substantial obligation of Tenant's tenancy and
Landlord shall be permitted to exercise any of its rights or remedies pursuant
to the terms of this Lease.

     35.2  The parties recognize and agree that the damage to Landlord resulting
from any breach of the covenants in Section 35.1 hereof will be substantial,
will be far greater than the Rent payable for the balance of the Term of this
Lease, and will be impossible of accurate measurement. The parties therefore
agree as follows:

           (a) In the event of a breach of the said covenants, in addition to
all of Landlord's rights and remedies, at law or in equity or otherwise,
Landlord shall have the right of injunction.

           (b) If Tenant breaches any of the covenants in Section 35.1 above,
and this Lease is terminated because of such default, then, anything in this
Lease to the contrary notwithstanding:

           (i) Landlord shall have the right to re-enter the Premises and resume
possession thereof, and to alter, reconstruct and Rent all or any part of the
Premises, at any Rental (to which Landlord shall agree), for any portion of or
beyond the original Term of this Lease.

           (ii) Any and all furniture, fixtures, equipment, goods, wares,
merchandise and any property of every kind and nature remaining in the Premises
shall be conclusively presumed to have been abandoned by Tenant, and Landlord,
without liability whatsoever or notice to anyone, may enter the Premises and
remove therefore any such furniture, fixtures, equipment, goods, wares,
merchandise and property of every kind and nature and dispose of the same in
such manner and upon such basis as Landlord may deem proper or advisable without
any liability to or duty to account therefore to Tenant.

           (iii) Any income received by Landlord on any such re-rental shall be
property of Landlord alone as compensation for the expenses in connection with
the preparation and re-renting of the Premises, and, together with the Rental
payable as aforesaid, as liquidated damages for the breach of Tenant, which
damage cannot be computed, as aforesaid. Tenant shall have no right to any
portion of such income, and such damages shall be cumulative for Tenant's
default under this Lease.

                                     -53-
<PAGE>
                                  ARTICLE 36
                         Non-Liability/Indemnification
                         -----------------------------

     36.1  Neither Landlord nor any partner, member, director, officer, agent,
servant or employee of Landlord shall be liable to Tenant for any loss, injury,
damage or loss, except to the extent the same are caused by or result from the
negligence of Landlord, its agents, servants or employees in the operation or
maintenance of the Premises or the Building. Further, neither Landlord nor any
partner, member, director, officer, agent, servant or employee of landlord shall
be liable (a) for any such damage caused by other tenants or persons in, upon or
about the Building or caused by the operations in construction of any private,
public or quasi-public work; or (b) even if negligent, for consequential damages
arising out of any loss of use of the Premises or any equipment or facilities
therein by Tenant or any person claiming through or under Tenant.

     36.2  Tenant shall indemnify and hold harmless Landlord and all lessors
under underlying leases, of, and mortgagees under mortgages affecting, the Land
and/or the Building and its and their respective partners, members, directors,
officers, agents and employees from and against any and all claims arising from
or in connection with (a) the use or occupation of the Premises by Tenant or
anyone in the Premises with Tenant's permission, or the conduct or management of
the Premises or of any business therein, or any work or thing whatsoever done,
or any condition created (other than by Landlord, its agents, servants or
employees) in or about the Premises during the Term of this Lease or during the
period of time, if any, prior to the Lease or during the period of time, if any,
prior to the Commencement Date, that Tenant may have been given access to the
Premises) (b) any act, omission or negligence of Tenant or any of its sublessees
or licensees or its or their partners, members, directors, officers, agents,
employees or contractors; (c) any accident, injury or damage whatsoever (except
to the extent caused by the negligence of Landlord, its agents, servants or
employees) occurring in, at or upon the Premises or in the Building, including
the roof of the Building; and (d) any breach or default by Tenant in the full
and prompt payment and performance of Tenant's obligations under this Lease but
only to the extent set forth in Article 17 of this Lease. Tenant's indemnity
shall include the payment to Landlord of all costs, and expenses incurred in or
in connection with each such claim or action or proceeding brought thereon,
including without limitation, all reasonable attorneys' fees, costs and
expenses. In case any action or proceeding shall be brought against Landlord
and/or any such lessor or mortgagee and/or its or their partners, directors,
officers, agents and/or employees by reason of such claim, Tenant, upon written
notice from Landlord or such lessor or mortgagee (as the case may be), shall
resist and defend such action or proceeding (by counsel reasonably satisfactory
to Landlord).

                                   ARTICLE 37

                                 Miscellaneous
                                 -------------

     37.1  Irrespective of the place of execution or performance, this Lease
shall be governed and construed in accordance with the laws of the State of New
York.

     37.2  This Lease shall be construed without regard to any presumption or
other rule requiring construction against the party causing this Lease to be
drafted.

                                      -54-
<PAGE>

     37.3  Except as otherwise expressly provided in this Lease, each covenant,
agreement, obligation or other provision of this Lease on Tenant's part to be
performed shall be deemed and construed as a separate and independent covenant
of Tenant, not dependent on any other provision of this Lease.

     37.4  All terms and words used in this Lease, regardless of the number or
gender in which they are used, shall be deemed to include any other number and
other gender as the context may require.

     37.5  Time shall be of the essence with respect to the exercise of any
option granted under this Lease.

     37.6  Except as otherwise provided in this Lease, whenever the payment of
interest is required to be made by Tenant to Landlord by the terms hereof it
shall be at the Interest Rate.

     37.7  In the event that Tenant is in arrears in the payment of fixed annual
rent or additional rent hereunder, Tenant waives Tenant's right, if any, to
designate the items against which any payments made by Tenant are to be
credited, and Tenant agrees that Landlord may apply any payments made by Tenant
to any items it sees fit, irrespective of and notwithstanding any designation or
request by Tenant as to the items against which any such payments shall be
credited.

     37.8  The submission of this document for examination does not constitute
an option or an offer to lease space in the Building. This Lease shall have no
binding effect on the parties unless executed by Landlord and Tenant and a fully
executed copy is delivered to Landlord and Tenant.

     37.9  The captions are inserted only as a matter of convenience and for
reference, and in no way define, limit or describe the scope of this Lease or
the intent of any provision hereof.

     37.10 This Lease may be executed in one or more counterparts, each of which
shall be deemed an original, but all of which together shall constitute one and
the same instrument.

     37.11 Landlord shall have the full right at any time to name and change the
name of the Building and to change the designated address of the Building. The
Building may be named after any person, firm, or otherwise, whether or not such
name is, or resembles, the name of a tenant of the Building.

     IN WITNESS WHEREOF, Landlord and Tenant have respectively executed this
Lease as of the day and year first above written.

                                      -55-
<PAGE>

                                   LANDLORD:

                                 404 FIFTH LLC

                         By:  /s/ Joseph Chetrit
                            -----------------------------
                            Name:
                            Title:

                         TENANT:

                         MAINSPRING COMMUNICATIONS, INC.

                         By:   /s/ Stephen E. Henkenmeier
                             ----------------------------
                            Name: Stephen E. Henkenmeier
                            Title: Director of Operations

                                      -56-
<PAGE>

                                  SCHEDULE A

                     Diagrams of Entire 7/th/ and 8/th/ Floors

                                      A-1
<PAGE>

                                   SCHEDULE B

                               Lobby "Rendering"
                               -----------------

                                      B-1
<PAGE>

                                  SCHEDULE C

                            Form of Estoppel Letter

[Date]

[Addressee]

          Re:  Lease     dated ____________________________ Between
              ___________________________ Lessor, and _______________ Lessee,
              for premises located on _____________________ in the building at
              404 Fifth Avenue, New York, New York

Ladies and Gentlemen:

          The undersigned, as Lessee, has been advised that the above described
lease (the "Lease") has been or will be assigned to you as security for a
mortgage loan to _____________________ a ___________________ and as an
inducement therefor hereby confirms the following:

          1.  That it has accepted possession of the premises demised pursuant
to the terms of the Lease and that the Lease is in full force and effect.

          2.  To the best of Tenant's knowledge, that the improvements and space
required to be furnished according to the Lease have been completed in all
respects.

          3.  To the best of Tenant's knowledge, that the Lessor has fulfilled
all of its duties of an inducement nature and that neither the undersigned nor
the Lessor is currently in default under the terms, covenants and obligations of
the Lease.

          4.  That the Lease has not been modified, altered or amended, except
for ________

          5.  To the best of Tenant's knowledge, that there are no offset,
counterclaims or credits against rentals, nor have rentals been prepaid, except
as provided by the Lease terms.

          6.  That rentals under the Lease commenced on the _____ day of
__________, 1999. The lease term expires years from that date, or the__ day of
________, 19__.

          7   That the undersigned has no notice of a prior assignment,
hypothecation or pledge of rents or the Lease.

                                      C-1
<PAGE>

          8.  That in the event of a default by Lessor under the Lease, Lessee
shall give you prompt written notice of such default at the address set forth
hereinabove and a reasonable opportunity to cure said default in a time and
manner as set forth in the Lease before we exercise any of our rights under the
Lease which we would have by reason of the occurrence of such default.

          9.  That Lessee will cause you to be named as an insured, as your
interest may appear; by standard mortgage clause, under all applicable policies
of insurance required to be maintained by the Lessee under the Lease, which
policies of insurance will specifically provide for non-cancellation and no
material modification without 30 days' prior written notice to you.

          10. That notwithstanding the above-referenced assignment of the Lease
to you, Lessee understands and acknowledges that (i) all rental and other
payments due under the terms of the Lease shall continue to be paid in
accordance with the terms of the Lease until and unless Lessee is notified to
the contrary in writing by you; and (ii) you assume no duty, liability or
obligation under the Lease, either by virtue of said assignment, the exercise of
remedies thereunder, or any subsequent receipt or collection of rentals or any
other sums due under the terms of the Lease.

          11. That subject to the terms of the Lease, Lessee shall comply with
and be bound by all of the terms, covenants and obligations of the Lease.
Subject to the terms of the Lease, no cancellation or modification of the Lease
or waiver or consent under the terms of the Lease or prepayment of or reduction
in rental under the Lease shall be effective without your prior written consent.

          12. That if, by foreclosure, or otherwise, you, your successors or
assigns, or any purchaser at or after foreclosure sale or otherwise, shall come
into possession of or become the owner of the premises demised by Lease, then:

          (a) Lessee agrees to attorn to, be liable to, and recognize you or
such successor, assign or purchaser as Lessor under the Lease and to be bound by
and to perform all of the obligations imposed by the Lease upon Lessee, and you,
such successor, assign or purchaser shall succeed to all of the rights of Lessor
under the Lease; and

          (b) provided that no default then exists under the terms and covenants
of the Lease beyond applicable notice and grace periods, you or such successor,
assign or purchaser will not disturb the occupancy of Lessee under the Lease,
except in accordance with the terms of the Lease, and shall be bound by all of
the obligations imposed by the Lease upon Lessor in accordance with the terms
thereof, set only for and during such respective period of time as you or such
successor, assign or purchaser shall possess or own the said premises.

          13. That you shall not be (i) liable for any act or omission of any
person or party who may be a Lessor under the Lease prior' to your acquisition
of title to said premises ("Prior Lessor") or (ii) subject to any offset or
defenses which Lessee may have against any Prior Lessor.

                                      C-2
<PAGE>

          14. That this letter shall inure to your benefit and to the benefit
of your successors and assigns and shall be binding upon Lessee and Lessee's
heirs, personal representatives, successors and assigns.

          The above statements are made with the understanding that you will
rely on them in connection with the above-mentioned loan.

                             Very truly yours,

                           [attach acknowledgments]

                                      C-3
<PAGE>

                                   SCHEDULE D

                             RULES AND REGULATIONS
                             ---------------------

          1.  The rights of tenants in the entrances, corridors, elevators and
escalators of the Building are limited to ingress to and egress from the
tenants' premises for the tenants and their employees, licensees and invitees,
and no tenant shall use, or permit the use of, the entrances, corridors,
escalators or elevators for any other purpose. No tenant shall invite to the
tenant's premises, or permit the visit of, persons in such numbers or under such
conditions as to interfere with the use and enjoyment of any of the plazas,
arcades, entrances, corridors, escalators, elevators and other facilities of the
Building by other tenants. Fire exits and stairways are for emergency use only,
and they shall not be used for any other purposes by the tenants, their
employees, licensees or invitees. No tenant shall encumber or obstruct, or
permit the encumbrance or obstruction of any of the sidewalks, plazas, arcades,
entrances, corridors, escalators, elevators, fire exits or stairways of the
Building. Landlord reserves the right to control and operate the public portions
of the Building and the public facilities, as well as facilities furnished for
the common use of the tenants, in such manner as it deems best for the benefit
of the tenants generally.

          2.  The cost of repairing any damage to the public portions of the
Building or the public facilities or to any facilities used in common with other
tenants, caused by a tenant or the employees, licensees or invitees of the
tenant, shall be paid by such tenant.

          3.  Landlord may refuse admission to the Building outside of Business
Hours on Business Days (as such terms are defined in the lease to which these
Rules and Regulations are annexed) to any person not known to the watchman in
charge or not having a pass issued by Landlord or not properly identified, and
may require all persons admitted to or leaving the Building outside of Business
Hours on Business Days to register. Each tenant shall be responsible for all
persons for whom it requests such permission and shall be liable to Landlord for
all acts or omissions of such persons. Any person whose presence in the Building
at any time shall, in the reasonable judgment of Landlord, be prejudicial to the
safety of the Building or its tenants may be denied access to the Building or
may be ejected therefrom. In case of invasion, riot, public excitement or other
commotion Landlord may prevent all access to the Building during the continuance
of the same, by closing the doors or otherwise, for the safety of the tenants
and protection of property in the Building.

          4.  No tenant shall obtain or accept or use in its premises towel,
barbering, boot blacking, floor polishing, lighting maintenance, cleaning or
other similar services from any persons not authorized by Landlord in writing to
furnish such services, provided that the charges for such services by persons
authorized by Landlord are comparable to charges for similar services in other
first-class office buildings in New York County. Such services shall be
furnished only at such hours, in such places within the tenant's premises and
under such regulations as may be fixed by Landlord from time to time.

                                      D-1
<PAGE>

          5.  No awnings or other projections over or around the windows shall
be installed by any tenant.

          6.  There shall not be used in any space, or in the public halls of
the Building, either by tenants or by jobbers or others, in the delivery or
receipt of merchandise or mail any hand trucks, except those equipped with
rubber tires.

          7.  All entrance doors in each tenant's premises shall be left locked
when the tenant's premises are not in use. Entrance doors shall not be left open
at any time. Each tenant, before closing and leaving its premises at any time,
shall turn out all lights. Blinds shall be installed and maintained on all
windows in the Premises and all windows shall be kept closed at all times and
all blinds or drapes therein above the ground floor shall be lowered or closed
when and as reasonably required because of the position of the sun during the
operation of the Building air-conditioning system to cool or ventilate the
tenants' premises.

          8.  The sashes, sash doors, skylights, windows and doors that reflect
or admit light and air into the halls, passageways or other public places in the
Building shall not be covered or obstructed by any Tenant, nor shall any
bottles, parcels or other articles be placed on the window sills or on the
peripheral air-conditioning enclosures, if any.

          9.  No showcases or other articles shall be put in front of or affixed
to any part of the exterior of the Building, nor placed in the halls, corridors
or vestibules.

          10. No noise, including the playing of any musical instruments, radio
or television, which, in the judgment of Landlord, might disturb other tenants
in the Building shall be made or permitted by any tenant and no cooking (except
for microwave cooking) shall be permitted in the tenant's premises except in any
kitchen or dwyer units installed in the Premises with Landlord's approval.
Nothing shall be done or permitted in any tenant's premises, and nothing shall
be brought into or kept in any tenant's premises, which would impair or
interfere with any of the Building services or the proper and economic heating,
cleaning or other servicing of the Building or the premises, or the use or
enjoyment by any other tenant of any other premises, nor shall there be
installed by any tenant any ventilating, air conditioning, electrical or other
equipment of any kind which, in the judgment of Landlord, might cause any such
impairment or interference.

          11. No dangerous, inflammable, combustible or explosive object or
material shall be brought into the Building by any tenant or with the permission
of any tenant, other than as may be used as an incidental to normal office use
in connection with cleaning or photocopying equipment.

          12. No tenant shall permit any cooking or food odors emanating within
its premises to seep into other portions of the Building.

                                      D-2
<PAGE>

          13.  No acids, vapors or other materials shall be discharged or
permitted to be discharged into the waste lines, vents or flues of the Building
which may damage them. The water and wash closets and other plumbing fixtures in
or serving any tenant's premises shall not be used for any purpose other than
the purpose for which they were designed or constructed and no sweepings,
rubbish, rags, acids or other foreign substances shall be deposited therein. All
damages resulting from any violation of this rule shall be borne by the tenant
who, or whose servants, employees, agents, visitors or licensees, shall have
caused the same. Any cuspidors or containers or receptacles used as such in the
Premises shall be emptied, cared for and cleaned by and at the expense of such
tenant.

          14. No signs, advertisement, notice or other lettering shall be
exhibited, inscribed, painted or affixed by any tenant on any part of the
outside of the Building without the prior written consent of Landlord. Landlord
shall not unreasonably withhold consent to the installation of an appropriate
sign identifying Tenant in the entrance to the premises. Interior signs and
lettering on doors and elevators shall be inscribed, painted, or affixed for
each by Landlord at the expense of such tenant, and shall be of a size, color
and style acceptable to Landlord. In the event of the violation of the foregoing
by any tenant, Landlord may remove the same without any liability, and may
charge the expense incurred in connection with such removal to the tenant or
tenants violating this rule. Landlord shall have the right to prohibit any
advertising by any tenant which impairs the desirability of the Building as a
building for offices, and upon written notice from Landlord, the tenant shall
refrain from or discontinue such advertising.

          15. Additional locks or bolts of any kind which shall not be operable
by the Grand Master Key for the Building shall not be placed upon any of the
doors or windows by any tenant nor shall any changes be made in locks or the
mechanism thereof which shall make such locks inoperable by the Grand Master
Key. Duplicate keys for a tenant's premises and toilet rooms shall be procured
only from Landlord, which may make a reasonable charge therefor. Upon the
termination of a tenant's lease, all keys of the tenant's premises and toilet
rooms shall be delivered to Landlord.

          16. No tenant shall mark, paint, drill into, or in any way deface any
part of the Building or (except for the tenant's installation and normal
decorating and the installation of ordinary business office equipment) the
premises demised to such tenant. No boring, cutting or stringing of wires shall
be permitted, except with the prior written consent of Landlord, and as Landlord
may direct.

          17. No tenant shall install any resilient tile or similar floor
covering in the premises demised to such tenant except in a manner approved by
Landlord.

          18. No tenant or occupant shall engage or pay any employees in the
Building, except those actually working for such tenant or occupant in the
Building or advertise for laborers giving an address at the Building.

                                      D-3
<PAGE>

          19. No premises shall be used, or permitted to be used, at any time,
as a store for the sale or display of goods or merchandise of any kind, or as a
restaurant, shop, booth, bootblack or other stand, or for the conduct of any
business or occupation which involved direct patronage of the general public in
the premises demised to such tenant, or for manufacturing or for other similar
purposes.

          20. No bicycles, vehicles, animals (except seeing eye dogs), fish or
birds of any kind shall be brought into or kept in or about the premises of any
tenant or the Building.

          21. The requirements of tenants will be attended to only upon
application at the office of the management agent of the Building. Employees of
Landlord shall not perform any work or do anything outside of the regular duties
unless under special instructions from the office of Landlord.

          22. Each tenant shall, at its expense, provide artificial light in the
premises demised to such tenant for Landlord's agents, contractors and employees
while performing janitorial or other cleaning services and making repairs or
alterations in said premises.

          23. The tenant's employees shall not loiter around the hallways,
stairways, elevators, front, arcade roof or any other part of the Building used
in common by the occupants thereof.

          24. All removals, or the carrying in or out of any safes, freight,
furniture, packages, boxes, crates or any other object or matter of any
description must take place during such hours and in such elevators and in such
manner as Landlord or its agent may determine from time to time. The persons
employed to move safes and other heavy objects shall be reasonably acceptable to
Landlord, and if so required by law, shall hold a Master Rigger's license.
Arrangements will be made by Landlord with any tenant for moving large
quantities of furniture and equipment into or out of the Building. All labor and
engineering costs incurred by Landlord in connection with any moving specified
in this rule, shall be paid by the tenant to Landlord, on demand.
Notwithstanding anything to the contrary contained in this paragraph 24, the
nonexclusive use of the freight elevator shall be available to Tenant during
Business Hours during the first sixty (60) days after the commencement of
construction regarding the Tenant's Work. Construction equipment and machinery
may only be transported in the freight elevator during Non-Business Hours and
the nonexclusive use of the freight elevator shall be made available to Tenant
on a first come, first serve basis during Non-Business Hours. Landlord shall
bear the cost of operating the nonexclusive use of the freight elevator during
Business Hours and Tenant shall pay for the cost of the operator of the
nonexclusive use of the freight elevator for the period of Tenant's use during
Non-Business Hours.

          25. Landlord reserves the right to inspect all objects and matter to
be brought into the Building and to exclude from the Building all objects and
matter which violate any of these Rules and Regulations or the lease to which
this Schedule is attached. Landlord may require any person leaving the Building
with any package or other object or matter to submit a pass, listing such

                                      D-4
<PAGE>

package or object or matter, from the tenant from whose premises the package or
object or matter is being removed, but the establishment and enforcement of such
requirement shall not impose any responsibility on Landlord for the protection
of any tenant against the removal of property from the premises of such tenant.
Landlord shall in no way be liable to any tenant for damages or loss arising
from the admission, exclusion or ejection of any person to or from the premises
or the Building under the provisions of this Rule.

          26.  No tenant shall occupy or permit any portion of its premises to
be occupied as an office for a public stenographer or public typist, or for the
possession, storage, manufacture, or sale of narcotics, dope, tobacco in any
form, or as a barber, beauty or manicure shop, or as a school or employment
bureau. No tenant shall use its premises or permit any part thereof to be used,
for manufacturing, or the sale at retail or auction of merchandise, goods or
property of any kind to the general public.

          27.  Landlord shall have the right to prohibit any advertising or
identifying sign by any tenant which, in Landlord's judgment, tends to impair
the reputation of the Building or its desirability as a building for others, and
upon written notice from Landlord, such tenant shall refrain from and
discontinue such advertising or identifying sign.

          28.  Landlord shall have the right to prescribe the weight and
position of safes and other objects of excessive weight, and no safe or other
object whose weight exceeds the lawful load for the area upon which it would
stand shall be brought into or kept upon any tenant's premises. If, in the
judgment of Landlord, it is necessary to distribute the concentrated weight of
any heavy object, the work involved in such distribution shall be done at the
expense of the tenant and in such manner as Landlord shall determine.

          29.  No machinery or mechanical equipment other than ordinary portable
business machines may be installed or operated in any tenant's premises without
Landlord's prior written consent, and in no case (even where the same are of a
type so excepted or as so consented to by Landlord) shall any machines or
mechanical equipment be so placed or operated as to disturb other tenants; but
machines and mechanical equipment which may be permitted to be installed and
used in a tenant's premises shall be so equipped, installed and maintained by
such tenant as to prevent any disturbing noise, vibration or electrical or other
interference from being transmitted from such premises to any other area of the
Building.

          30.  Tenant, at its sole cost and expense, shall cause its premises to
be exterminated, from time to time, to the satisfaction of Landlord, and shall
employ such exterminators therefor as shall be reasonably approved by Landlord.

          31.  No premises of any tenant shall be used for lodging or sleeping
or for any immoral or illegal purpose.

                                      D-5
<PAGE>

          32.  Canvassing, soliciting and peddling in the Building are
prohibited and each tenant shall cooperate to prevent the same.

          33.  Landlord reserves the right to rescind, alter or waive any rule
or regulation at any time prescribed for the Building when, in its judgment, it
deems it necessary, desirable or proper for its best interest and for the best
interests of the tenants, and no alteration or waiver of any rule or regulation
in favor of one tenant shall operate as an alteration or waiver in favor of any
other tenant. Landlord shall not be responsible to any tenant for the non-
observance or violation by any other tenant of any of the rules and regulations
at any time prescribed for the Building.

                                      D-6
<PAGE>

                                   SCHEDULE E
                                   ----------

                       CONSTRUCTION RULES AND REGULATIONS
                       ----------------------------------

          Except as otherwise provided for in the Lease:

          1.  Final architectural and mechanical blueprints of proposed
alterations shall be submitted to Landlord for written approval.

          2.  Tenant's general contractor and/or subtenant-contractors shall
submit certificates of insurance prior to starting Tenant's Initial Work and
Alterations ("Work") including worker's compensation, disability, liability and
property damage with the name of the Landlord, its agents and employees, as
additional insureds.

          3.  General Contractor will submit a list of all subtenant-contractors
to the Landlord. All subtenant-contractors will need to sign in at the building
and sign out. In addition, all workers must use the freight elevator, or if
there exists, a passenger freight. Workmen cannot use the Passenger Elevators,
unless only option in building.

          4.  Work which potentially can disturb neighboring tenants such, as
demolition, must be done before 9:00 a.m. and after 5:00 p.m. In addition, if
Work needs to be done after Business Hours, Tenant is responsible for paying the
cost for the overtime of the building staff member as provided for in the Lease.

          5.  The use of freight elevators for hoisting contractor's material,
equipment, rubbish, must be arranged with the property manager and
Superintendent to avoid conflict with regular building operations. If major
quantities of contractor's material is being brought to the job, exclusive use
of the freight car before and after regular building hours is to be instituted.
Tenant is responsible for paying the cost to operate the freight elevator on an
overtime basis.

          6.  Tenant's architect or general contractor shall file plans with all
governmental agencies and provide the Landlord with all permits, approved plans
stamped by the Building Department and electrical and plumbing
certificates/permits. At the end of the Work, all sign-offs for plumbing, fire
safety etc. must be turned over to Landlord.

          7.  Tenant's general contractor or subtenant-contractor will employ
labor and use materials which will not result in any labor disputes or any
interruption of the Building's daily operation.

          8.  All public areas including elevators are to be protected by the
Tenant's General Contractor or Subtenant-contractor. All public areas need to be
kept clean. If there is any problem, the building staff will clean and then be
charged for the work.

                                      E-1
<PAGE>

          9.  Any burning and/or welding will require a fire watch by the trade
performing such operation. Anyone using burning or welding apparatus shall be
duly certified.

          10. Walls and floors in corridors adjacent to construction areas and
leading to the freight elevators are to be protected with masonite or equivalent
with special protection for corners.

          11. Draining and refilling of any and all domestic water risers to be
performed by building staff at Tenant's expense and must be arranged with 48
hours notice. If other tenants are affected by draining risers, it cannot be
done during the day, and must be done on overtime.

          12. All sprinkler shut downs must be scheduled with the building staff
with 24 hours advanced notice. The cost of each shut down is $150.00 per
occurrence and will appear as a Tenant Charge except that there will be no such
charge in connection with Tenant's Initial Work. If the property is not a 24
hour a day building, additional charges may be incurred if a fire watch is
required.

          13. Any construction to be done that is after regular working hours
including weekends is to be arranged beforehand through the building office.

          14. Nothing in the aforementioned conditions shall be deemed as
superseding any part of the Lease or the Work Letter with the Landlord and in
the event of any conflicts between the conditions contained in the Lease and the
Work Letter and these Rules and Regulations, the Lease and the Work Letter shall
prevail.

                                      E-2
<PAGE>

                                  Exhibit "A"

                                  Work Letter

          1.  General.  All capitalized terms used herein and not otherwise
              -------
defined in this work letter (the "Work Letter") shall have the meanings ascribed
to them in this Lease. The terms and conditions of this Work Letter are
incorporated into the Lease and made a part thereof.

          2.  Preparation and Submission of Plans and Specifications.  Tenant
              ------------------------------------------------------
shall cause its architect to submit to Landlord, for Landlord's approval, plans
and specifications (the "Initial Plans and Specifications") for the construction
of Tenant's initial improvements and alterations to the Premises ("Tenant's
Initial Work"), which approval shall not be unreasonably withheld or delayed.
Landlord shall review the Initial Plans and Specifications, or any portion of
the Initial Plans and Specifications submitted to Landlord by Tenant, and within
fourteen (14) days of its receipt thereof, Landlord shall inform Tenant, in
writing, if the Initial Plans and Specifications are approved or if they require
further modification and, in such event, specifically how the Initial Plans and
Specifications need to be modified. In the event that Landlord fails to inform
Tenant that the Initial Plans and Specifications are either approved or require
further modification and, in such event, specifically how the Initial Plans and
Specifications need to be modified. In the event that Landlord fails to inform
Tenant that the Initial Plans and Specifications are either approved or require
further modification within such 14-day period, the Initial Plans and
Specifications shall be deemed to be approved by the Landlord.

          3.  Governmental Approvals and Permits.  Upon Landlord's approval of
              ----------------------------------
the Initial Plans and Specifications, Tenant shall file the same with the
appropriate governmental authorities and shall take whatever other action shall
be necessary to obtain and maintain in effect throughout the performance of
Tenant's Initial Work. Landlord shall cooperate with Tenant in promptly
executing any necessary documentation requested by Tenant in order to obtain all
governmental permits and authorizations that Tenant may require in connection
with Tenant's Initial Work. Upon the completion of Tenant's Initial Work and
prior to release of the Ten Percent Holdback (as hereinafter defined), Tenant
shall obtain all certificates and approvals required to be issued by any public
authority or any governmental authorities having jurisdiction over Tenant's
Initial Work.

          4.  Landlord's Contribution; Excess Costs; Procedure for Payment.
              ------------------------------------------------------------

          A.  Landlord's Contribution.  Landlord shall pay for a portion of the
              -----------------------
Cost of the Work (as defined below) in an amount initially representing the sum
not to exceed $220,000.00 for the 7th floor of the Premises and after the
Landlord delivers possession of the 8th floor of the Premises to Tenant the
additional amount not to exceed the sum of $220,000.00 ("Landlord's
Contribution"), and Tenant shall pay for the entire Cost of the Work in excess
of the Landlord's Contribution. For purposes of this Lease, "Cost of the Work"
means the costs of labor and materials directly related to the performance of
Tenant's Initial Work, provided that Tenant may expend a portion of Landlord's
Contribution, not to exceed five percent (5%) of the total thereof, toward the

                                      A-1
<PAGE>

payment of so-called "soft costs" incurred by Tenant including, architectural,
consulting, engineering fees, furniture costs and moving expenses.

          B.  Procedure for Payment.  Landlord shall pay "soft costs" to Tenant
              ---------------------
and "hard costs" to Tenant's contractors, as requested by Tenant, in an amount
equal to ninety percent (90%) of each request for payment made by Tenant (a
"Draw Request") within twenty (20) days following the submission by Tenant of a
Draw Request. In the case of a Draw Request made for "hard costs," such Draw
Request shall be accompanied by: (i) invoices covering the portion of Tenant's
Initial Work for which Tenant is requesting payment; and (ii) a written
certification from Tenant's AIA licensed architect that the work described on
any such invoice has been completed substantially in accordance with the Initial
Plans and Specifications approved by Landlord, and that all contractors have
delivered to Tenant waivers of lien with respect to such work (copies of which
lien waivers shall be included with such architect's certification). In the case
of a Draw Request made for soft costs, such Draw Request shall be accompanied by
invoices for the goods purchased and/or services performed. Ten percent (10%) of
every Draw Request shall be held back ("Ten Percent Holdback") by Landlord until
all of Tenant's Initial Work is completed as set forth in Paragraph 10 of this
Work Letter. Tenant shall not submit a Draw Request more than once per calendar
month. If, at the time of the submission of any Draw Request, Tenant is in
default of any provision of this Lease beyond any applicable notice and cure
periods, Landlord shall not be obligated to pay any amounts of Landlord's
Contribution to Tenant until such time as Tenant shall have remedied such
default.

          5.  General Conditions.
              ------------------

          A.  Performance of Work.  Tenant shall cause Tenant's Initial Work to
              -------------------
be performed in a good and worker like manner and, except as provided otherwise
in Paragraph 5B of this Work Letter, substantially in accordance with the
Initial Plans and Specifications approved by Landlord.

          B.  Changes.  Any material changes to Tenant's Initial Work or to the
              -------
Initial Plans and Specifications necessitated by field conditions or otherwise
(each, a "Change Request") must be approved by Landlord in writing, which
approval shall not be unreasonably withheld or delayed.

          6.  Insurance.  Throughout the construction of Tenant's Initial Work,
              ---------
Tenant shall maintain or cause to be maintained the insurance required for
Alterations pursuant to Article 8 of this Lease.

          7.  Punch List Items. Within ten (10) days after the substantial
              ----------------
completion of Tenant's Initial Work, Landlord and Tenant, and their respective
architects shall make a final inspection of Tenant's Initial Work and such
parties shall jointly prepare a final "punch list." Tenant shall thereafter
cause its contractor to perform the work necessary to complete such "punch list"
as promptly as practicable.

          8.  Landlord's Expenses. With respect to Tenant's Initial Work, Tenant
              -------------------
shall pay to Landlord, as additional rent, within 10 days after written demand
therefor, which demand shall be accompanied by copies of any appropriate
invoices, the cost of any overtime or premium pay for

                                      A-2
<PAGE>

Landlord's employees where such overtime or premium pay work has been expressly
requested by Tenant.

          9.  Fire Alarm System.  Landlord shall make available to Tenant, at no
              -----------------
additional expense to Tenant, a commercially reasonable number of connection
points to the fire alarm system in the Building on each floor of the Premises
taking into consideration the size of each floor plate.

          10.  Ten Percent Holdback.  After certification by Tenant's architect
               --------------------
that Tenant's Initial Work has been completed in its entirety and in accordance
with paragraph 4B of this Work Letter, including all Punch List items, Landlord
shall pay to Tenant or Tenant's contractor(s) as required, the Ten Percent
Holdback amounts pursuant to paragraph 4B of this Work Letter.

                                      A-3

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