<PAGE>

                                                                 Exhibit 10.20

                      PARK SQUARE BUILDING COMMERCIAL LEASE

      THIS INSTRUMENT IS A LEASE, dated as of March 3, 2000, in which The LESSOR
      and LESSEE are the parties hereinafter named, and which relates to space
      in the building (the "Building") located at 31 Saint James Avenue, Boston,
      Massachusetts 02116. The parties to this instrument hereby agree with each
      other as follows:

1.    BASIC LEASE
      PROVISIONS: The following set forth basic data and, where appropriate,
                  constitute definitions of the terms hereinafter listed.

                  A.    BASIC DATA.

                        LESSOR: OMV Associates Limited Partnership

                        LESSOR'S Address: c/o Capital Properties Management,
                  Inc., 31 Saint James Avenue, Boston, MA 02116

                        LESSEE: PaperExchange.com, LLC a Massachusetts limited
                  liability corporation

                        LESSEE'S Original Address: 545 Boylston Street, 8th
                  Floor, Boston, MA 02116

                        LESSEE'S Notice Address (Section 20): The Premises

                        Basic Rent: $1,082,002.50/year       $42.75/psf

                                    As the same may be adjusted and/or abated in
                                    accordance with the terms of this lease.

                        Premises Rentable Area: Agreed to be 25,310 square feet
                  located on the fifth floor of the Building.

                        Permitted Uses: General office use.

                        Escalation Factor: 5.53%, as computed in accordance with
                  the Escalation Factor Computation.

                        Scheduled Completion Period: As defined in Section 26B.

                        Initial Term: Five years commencing on the Commencement
                  Date and expiring at the close of the day immediately
                  preceding the fifth anniversary of the Commencement Date,
                  except that if the Commencement Date shall be other than the
                  first day of a calendar month, the expiration of the Initial
                  Term shall be at the close of the day on the last day of the
                  calendar month on which such anniversary shall fall.

                        Temporary Tenancy: As described in Section 36.

                              Temporary Premises: Agreed to be 14,139 rentable
                        square feet located on the third floor of the building,
                        8,928 rentable square feet on the south side of the
                        corridor (Area A) and 5,211 rentable square feet on the
                        north side of the corridor (Area B) as shown on Exhibit
                        D attached hereto.

                              Temporary Premises Basic Rent:

<PAGE>

                              $300,453.75/yr $25,037.82/mo $21.25/sf

                              Temporary Premises Escalation Factor: None.

                        Security Deposit: $303,720 in cash or letter of credit,
                  as that amount may be adjusted in accordance with Section 5
                  below.

                        Base Operating Expenses: The actual Operating Expenses
                  for the calendar year commencing January 1, 2000 and ending
                  December 31, 2000.

                        Base Taxes: The actual Taxes for the Tax Year commencing
                  July 1, 2000 and ending June 30, 2001.

                        Electricity Cost: $1.50/sf per year payable to LESSOR.

                        Broker: CB Richard Ellis / Whittier Partners and
                  Insignia/ESG

                  B.    ADDITIONAL DEFINITIONS.

                        Agent: Capital Properties Management, Inc., 31 St. James
                  Avenue, Boston, Massachusetts 02116.

                        Business Days: 8:00 a.m. - 6:00 p.m. Monday through
                  Friday and Saturday 9:00 a.m. through 1 p.m. except New Year's
                  Day, President's Day, Patriot's Day, Memorial Day,
                  Independence Day, Labor Day, Columbus Day, Veterans' Day,
                  Thanksgiving Day, Christmas Day (and the following Monday when
                  any such day occurs on Sunday). Unless specifically referred
                  to herein as Business Days, all references in this Lease to
                  "days" shall mean calendar days.

                        Commencement Date: Thirty (30) days after the later of
                  a) the Premises is available for LESSOR to commence LESSOR'S
                  Work, b) the issuance of a building permit and c) commencement
                  by LESSOR of LESSOR'S Work.

                        Escalation Factor Computation: Premises Rentable Area
                  divided by 100% of building rentable area (445,765 square
                  feet).

                        Initial Public Liability Insurance: $1,000,000.00 per
                  occurrence (combined single limit) for property damage,
                  personal injury or death.

                        LESSOR'S Work: As defined in Section 26.

                        LESSOR'S Contribution: $303,720

                        LESSEE'S Contribution: As defined in Section 26

                        Final Plans: As defined in Section 26.

                        Premises: A portion of the Building as shown on Exhibit
                  A attached hereto.

                        Extended Term: As defined in Section 35.

                        First Offer Space: As defined in Section 37.

2.    PREMISES    A portion of the building owned by LESSOR consisting of
                  approximately


                                        2


<PAGE>

                  25,310 SQUARE FEET OF RENTABLE AREA ON THE FIFTH FLOOR OF THE
                  BUILDING AND SHOWN AS SUITE 500 on the plan attached hereto as
                  "Exhibit A" (the "Premises") together with the right to use in
                  common, with others entitled thereto, the hallways, stairways,
                  and elevators, necessary for access to said Premises, and
                  lavatories nearest thereto.

3.    TERM        The term of this lease shall be for five years commencing on
                  the Commencement Date, or earlier pursuant to Section 36 of
                  this lease and ending sixty months after the Commencement
                  Date.

4.    BASIC RENT  The LESSEE shall pay to the LESSOR rent at the rate described
                  in Section 1 of this Lease, payable in advance on the first
                  day of each month commencing on the Commencement Date or prior
                  in accordance with Section 36, without deduction or set off.

5.    SECURITY    Upon the execution of this lease, the LESSEE shall pay to the
      DEPOSIT     LESSOR a security deposit in cash or a letter of credit in the
                  amount of $303,720.00. The Security Deposit shall be
                  maintained in said amount and held without interest as a
                  security for LESSEE'S performance as therein provided and
                  refunded to the LESSEE at the end of this Lease subject to the
                  LESSEE'S satisfactory compliance with the condition thereof.
                  If LESSEE is not in default during the first twelve months of
                  the term, the security deposit shall be reduced by one months
                  rent to $253,100.00. If LESSEE is not in default during the
                  first twenty four months of the term the security deposit
                  shall be reduced to $202,480.00. If LESSEE is not in default
                  during the first thirty six months of the term the security
                  deposit shall be reduced to $151,860.00 and this shall remain
                  as security deposit for the balance of the Term and for any
                  Extended Term.

6.    ADDITIONAL  A. TAX. If, in any tax year, the real estate taxes on the land
      RENT        and buildings, of which the Premises are a part, are in excess
                  of the amount of the Base Taxes, as finally abated
                  (hereinafter called the "Base Year"), LESSEE will pay to
                  LESSOR, as additional rent hereunder, when and as designated
                  by notice in writing by LESSOR, the amount of the excess
                  multiplied by the Escalation Factor. If the LESSOR obtains an
                  abatement of any such excess real estate tax, a proportionate
                  share of such abatement, less the reasonable fees and costs
                  incurred in obtaining the same, if any, shall be refunded to
                  the LESSEE.

                  B. OPERATING. If, in any calendar year, the Operating Expenses
                  for the Property of which the Premises are a part, are in
                  excess of the amount of the Base Operating Expenses, LESSEE
                  will pay to LESSOR, as additional rent hereunder, within
                  thirty (30) days of receiving notice in writing by LESSOR, the
                  amount of the excess multiplied by the Escalation Factor.
                  Operating Expenses are defined for the purposes of this
                  agreement as: The aggregate costs or expenses reasonably
                  incurred by LESSOR with respect to the operation,
                  administration, cleaning, repair, maintenance and management
                  of the premises including, without limitation, those items
                  enumerated in "Exhibit C" attached hereto and excluding those
                  items shown as exclusions on Exhibit C. Any such accounting by
                  LESSOR shall be binding and conclusive upon LESSEE unless
                  within thirty (30) days after that giving by LESSOR of such
                  accounting, LESSEE shall notify LESSOR that LESSEE disputes
                  the correctness of such accounting, specifying the particular
                  respects in which the accounting is claimed to be incorrect.

                  C. PAYMENT. At LESSOR'S option, payment of Additional Rent
                  shall be on a monthly basis based on LESSOR'S good faith
                  estimate of the Tax and Operating Expenses for the following
                  year.


                                        3

<PAGE>

                  D. AUDIT. In the event LESSEE elects to audit LESSOR'S
                  statement of Operating Expenses or statement of Taxes in
                  accordance with this clause, such audit must be (i) conducted
                  by an independent nationally recognized accounting firm that
                  is not being compensated by LESSEE on a contingency fee basis,
                  and (ii) completed within sixty (60) days following LESSEE'S
                  notice disputing the correctness of the statement of Operating
                  Expenses or statement of Taxes. Furthermore, all of the
                  information obtained through the LESSEE'S audit with respect
                  to financial matters (including, without limitation, costs,
                  expenses, income) and any other matters pertaining to the
                  LESSOR and/or the Property as well as any compromise,
                  settlement, or adjustment reached between LESSOR and LESSEE
                  relative to the results of the audit shall be held in strict
                  confidence by LESSEE and its officers, agents, and employees;
                  and LESSEE shall cause its auditor and any of its officers,
                  agents, and employees to be similarly bound. As a condition
                  precedent to LESSEE'S exercise of its right to audit, LESSEE
                  must deliver to LESSOR a signed confidentiality agreement from
                  the auditor (in form reasonably acceptable to LESSOR) reached
                  between LESSOR and LESSEE shall be held in strict confidence
                  and shall not be revealed in any manner to any person except
                  upon the prior written consent of LESSOR. LESSEE understands
                  and agrees that this provision is of material importance to
                  the LESSOR and that any violation of the terms of this
                  provision shall result in immediate and irreparable harm to
                  the LESSOR. LESSOR shall have all rights allowed by law or
                  equity if LESSEE, its officers, agents, or employees and/or
                  the auditor violate the terms of this provision, including,
                  without limitation, the right to terminate LESSEE'S right to
                  audit.

7.    UTILITIES   The LESSEE shall pay, as they become due, all bills for
                  electricity and other utilities that are furnished to the
                  Premises and presently separately metered. The LESSOR agrees
                  to provide all other utility service and to furnish reasonably
                  hot and cold water and reasonable heat and air conditioning to
                  the Premises, the hallways, stairways, elevators, and
                  lavatories during normal building business hours on regular
                  business days of the heating and air conditioning seasons of
                  each year, to furnish elevator service and to light
                  passageways and stairways during business hours, and to
                  furnish such cleaning service as is customary in similar
                  buildings in Boston, Massachusetts, all subject to
                  interruption due to any accident, to the making of repairs,
                  alterations, or improvements, to labor difficulties, to
                  inability to obtain fuel, electricity, service, or supplies
                  from the sources from which they are usually obtained for said
                  building, or to any cause beyond the LESSOR'S control.

                  LESSOR shall have no obligation to provide utilities or
                  equipment other than the utilities and equipment within the
                  premises as of the Commencement Date of this lease. In the
                  event LESSEE requires additional utilities or equipment, the
                  installation and maintenance thereof shall be the LESSEE'S
                  sole obligation, provided that such installation shall be
                  subject to the written consent of the LESSOR, not to be
                  unreasonably withheld.

8.    USE OF      The LESSEE agrees to use the Premises in a manner consistent
      LEASED      with the nature of the building and consistent with the other
      PREMISES    LESSEES in the building. The LESSEE shall use the Premises
                  only for the purpose of listed in Section 1 of this Lease and
                  LESSOR represents that such use is a lawful one.

9.    COMPLIANCE  The LESSEE acknowledges that no trade or occupation shall be
      WITH LAWS   conducted in the Premises or use made thereof which will be
                  unlawful, improper, noisy or offensive, or contrary to any law
                  or any municipal by-law or ordinance in force in the city or
                  town in which the Premises are situated. LESSEE agrees to
                  comply with all such laws.


                                        4

<PAGE>

                  LESSOR makes no representation that uses contemplated by the
                  LESSEE are permitted by law.

10.   FIRE        The LESSEE shall not permit any use of the Premises which will
      INSURANCE   make voidable any insurance on the property of which the
                  Premises are a part, or on the contents of said property or
                  which shall be contrary to any law or regulation from time to
                  time established by the New England Fire Insurance Rating
                  Association, or any similar body, succeeding to its powers.
                  Nor shall LESSEE cause or permit the storage, use, generation,
                  release or disposition of any hazardous materials in, on or
                  about the property by LESSEE, its agents, employees or
                  contractors, other than small amounts of cleaning products and
                  the like used in the ordinary course of business in compliance
                  with all applicable laws. LESSEE will not permit the Premises
                  to be used or operated in a manner that may cause the Premises
                  or the property (the "Property") as defined in Exhibit B
                  attached hereto to be contaminated by any hazardous materials
                  in violation of any hazardous materials laws. LESSEE will
                  immediately advise LESSOR in writing of (1) any and all
                  enforcement, cleanup, remedial, removal, or other governmental
                  or regulatory actions instituted, completed, or threatened
                  pursuant to any hazardous materials laws relating to any
                  hazardous materials affecting the Premises; and (2) all claims
                  made or threatened by any third party against LESSEE, LESSOR,
                  the Premises or the Property relating to damage, contribution,
                  cost recovery, compensation, loss or injury resulting from any
                  hazardous materials on or about the Premises. Without LESSOR'S
                  prior written consent, LESSEE will not take any remedial
                  action or enter into any agreement or settlements in response
                  to the presence of any hazardous materials in, on, or about
                  the Premises.

                  LESSEE will be solely responsible for and will defend,
                  indemnify and hold LESSOR, its agents, and employees harmless
                  from and against all claims, costs, expenses, damages, and
                  liabilities, including employees harmless from and against all
                  claims, costs expenses, damages and liabilities, including
                  attorneys' fees and costs, arising out of or in connection
                  with LESSEE'S breach of its obligations in this Section 10.
                  LESSEE will be solely responsible for and will defend,
                  indemnify, and hold LESSOR, its agents, and employees harmless
                  from and against any and all claims, costs, and liabilities,
                  including attorneys' fees and costs, arising out of or in
                  connection with the removal, cleanup and restoration work and
                  materials necessary to return the Premises and any other
                  property of whatever nature located on the Property to their
                  condition existing prior to the appearance of LESSEE'S
                  hazardous materials on the Premises. LESSEE'S obligations
                  under this Section 10 will survive the expiration or other
                  termination of this Lease.

                  The LESSEE shall not use the Premises in any way which will
                  cause an extra insurance premium. LESSOR confirms that
                  LESSEE'S use of the Premises as general office space shall not
                  cause an extra insurance premium. However, in the event that
                  LESSEE does so, the LESSEE shall, on demand, reimburse the
                  LESSOR, and all other lessees, all extra insurance premiums
                  caused by the LESSEE'S use of the Premises.

11.   MAINTEN-    The LESSEE agrees to maintain the Premises, in good condition,
      ANCE OBLI-  reasonable wear and tear and damage by fire and other casualty
      GATIONS     only excepted, and whenever necessary, to replace plate glass
                  and other glass therein.

                  A. LESSEE'S OBLIGATIONS. The Premises are now in good order
                  and the glass whole. The LESSEE shall not permit the Premises
                  to be overloaded, damaged, stripped, or defaced, nor suffer
                  any waste. LESSEE shall obtain written consent of LESSOR
                  before erecting any sign on the Premises, provided LESSEE
                  shall not need any further consent of LESSOR to erect the
                  signs listed on Exhibit F. The LESSEE


                                        5

<PAGE>

                  shall keep and maintain the Premises in good order and repair
                  at its own expense. The LESSOR shall at LESSEE'S expense and
                  upon LESSEE'S request, furnish and install all replacement
                  lamps, lighting tubes, bulbs and ballast's which may be
                  required in the Premises during the terms hereof.

                  B. LESSOR'S OBLIGATIONS. The LESSOR agrees to maintain the
                  common areas and the structure and building systems of the
                  building in the same condition as it is at the commencement of
                  the Term or as it may be put in during the Term of this Lease,
                  reasonable wear and tear, damage by fire and other casualty
                  only excepted, unless such maintenance is required because of
                  the LESSEE or those for whose conduct the LESSEE is legally
                  responsible.

                  LESSOR shall never be liable for any failure to make repairs
                  in the Premises unless LESSEE has given notice to LESSOR of
                  the need to make such repairs and LESSOR has failed to
                  commence to make such repairs within a reasonable time after
                  receipt of such notice, or fails to proceed with reasonable
                  diligence to complete such repairs.

12.   ADDITIONS & The LESSEE shall not make structural alterations or additions
      ALTERATIONS to the Premises or the building's systems, but may make
                  non-structural alterations provided the LESSOR consents
                  thereto in writing, which consent shall not be unreasonably
                  withheld or delayed. LESSEE may make non-structural
                  alterations which cost less than $20,000 without LESSOR'S
                  consent, however, LESSEE must provide notice. All such allowed
                  alterations shall be at LESSEE'S expense and shall be in
                  quality at least equal to the present construction. LESSEE
                  shall not permit any mechanics' liens, or similar liens, to
                  remain upon the Premises for labor and material furnished to
                  LESSEE or claimed to have been furnished to LESSEE in
                  connection with work of any character performed or claimed to
                  have been performed at the direction of LESSEE and shall cause
                  any such lien to be released of record forthwith without cost
                  to LESSOR. If such lien is not discharged within ten (10) days
                  after notice to LESSEE of such filing of such lien, LESSEE
                  shall furnish LESSOR, within such ten (10) day period,
                  security satisfactory to LESSOR in the amount of 150% of the
                  claim plus estimated costs to discharge the lien. Any
                  alterations or improvements made by the LESSEE shall become
                  the property of the LESSOR at the termination of occupancy as
                  provided herein.

13.   ASSIGNMENT  The LESSEE shall not assign or sublet the whole or any part of
      & SUBLEAS-  the Premises without LESSOR'S prior written consent, such
      ING         consent shall not be unreasonably withheld or delayed and
                  shall be provided within thirty (30) days of LESSEE'S request.
                  Notwithstanding such consent, LESSEE shall remain liable to
                  LESSOR for the payment of all rent and for the full
                  performance of the covenants and conditions of this lease. If
                  SUBLESSEE or ASSIGNEE is paying rent at an amount greater than
                  in this agreement, fifty percent (50%) of the proceeds after
                  expenses shall be due to LESSOR. No assignment or sublease
                  shall release LESSEE from, and LESSEE shall remain fully
                  liable for, performance of LESSEE'S obligations under the
                  lease. LESSEE shall not sublease or assign to a current or
                  prospective tenant of the Building. Prospective tenants are
                  those tenants who have been introduced to the Property within
                  thirty (30) days of the sublease or assignment proposal or any
                  tenant in negotiation with LESSOR. LESSEE shall not sublease
                  below Fair Market Value, without LESSOR'S prior written
                  consent. LESSEE shall not sublease or assign to any tenant
                  whereby the sublessee or assignees use violates the exclusive
                  use of any tenant at the Property.

                  (a) Submission of Information. If LESSEE requests LESSOR'S
                  consent to a specific assignment or subletting, LESSEE will
                  submit in writing to LESSOR (a) the name and address of the
                  proposed assignee or subtenant; (b) the business terms of the
                  proposed


                                        6

<PAGE>

                  assignment or sublease; (c) reasonably satisfactory
                  information as to the nature and character of the business of
                  the proposed assignee or subtenant, and as to the nature of
                  its proposed use of the space; (d) banking, financial, or
                  other credit information reasonably and character of the
                  proposed assignee or subtenant; (e) the proposed form of
                  assignment (including lease assumption provisions) or
                  sublease; and (f) any other information reasonably required by
                  Landlord.

                  (b) LESSOR'S Options. In the event of LESSEE'S request for an
                  assignment or sublease of this Lease or of all or any part of
                  the Premises by LESSEE, LESSOR in addition to any rights
                  contained herein, shall have the following options at its
                  discretion:

                        (i)   to give LESSEE written notice of LESSOR'S
                              intention to terminate this Lease as to all or any
                              portion of the Premises on the date such notice is
                              given or on any later date specified therein,
                              whereupon, on the date specified in such notice,
                              LESSEE'S right to possession of the Premises or
                              such portion of the Premise shall cease and this
                              Lease shall thereupon be terminated, except as to
                              any incomplete obligations of LESSEE; or

                        (ii)  to re-enter and take possession of the Premises or
                              the part thereof subject to such transfer, and to
                              enforce all rights of LESSEE, in accordance with
                              such sublet or assignment of the Premises, or any
                              part thereof, as if LESSOR was the sublessor or
                              assignor, and to do whatever LESSEE is permitted
                              to do pursuant to the terms of such sublease or
                              assignment.

                  If LESSOR so elects to exercise it's rights under this Section
                  13(b), LESSEE may, within three (3) days of notice from
                  LESSOR, withdraw its request to assignment or sublease and
                  LESSOR shall have no further rights under this Section in
                  regard to that specific request to assign or sublease.

                  (c) Permitted Transfer. LESSOR consents to an assignment of
                  this Lease or sublease of all or part of the Premises to a
                  wholly-owned subsidiary of LESSEE or the parent of LESSEE or
                  to any corporation into or with which LESSEE may be merged,
                  consolidated or purchases all of LESSEE'S assets; provided
                  that (a) LESSEE promptly provides LESSOR with a fully executed
                  copy of such assignment or sublease; (b) LESSEE is not
                  released from liability under this Lease and (c) the assignee
                  assumes in writing all of the obligations of LESSEE under this
                  Lease.

14.   SUBORDINA-  This Lease shall be subject and subordinate to any and all
      TION        mortgages, deeds of trust and other instruments in the nature
                  of a mortgage, now or at any time hereafter, a lien or liens
                  on the property of which the Premises are a part and the
                  LESSEE shall, when requested, promptly execute and deliver
                  such written instruments as shall be necessary to show the
                  subordination of this lease to said mortgages, deeds of trust
                  or other such instruments in the nature of a mortgage. In the
                  event that LESSEE fails or refuses to execute same, LESSOR may
                  do so as LESSEE'S Attorney-in-Fact. LESSOR shall secure a
                  so-called subordination and non-disturbance agreement from
                  LESSOR'S Mortgagee within forty-five (45) days of LESSOR's
                  execution of this Lease.

15.   LESSOR'S    The LESSOR or agents of the LESSOR may, at reasonable times
      ACCESS      and with reasonable notice, enter to inspect the Premises;
                  exhibit the Premises to prospective purchasers, lenders or
                  tenants; determine LESSEE'S compliance with the Lease; remove
                  placards and signs not approved and affixed as herein
                  provided, and make repairs and alterations to the Premises and
                  Property as LESSOR should elect to do. LESSOR shall


                                        7

<PAGE>

                  use reasonable efforts to minimize interference with
                  operations of LESSEE'S business at the Premises.

16.   INDEMNIFI-  LESSEE shall save LESSOR harmless, and shall exonerate and
      CATION AND  indemnify LESSOR, from and against any and all claims,
      LIABILITY   liabilities or penalties asserted by or on behalf of any
                  person, firm, corporation or public authority:

                  (i)   on account of or based upon any injury to person, or
                        loss of or damage to property sustained or occurring or
                        emanating from the Premises on account of or based upon
                        the act, omission, fault, negligence or misconduct of
                        any person except LESSOR, its agents officers or
                        employees;

                  (ii)  on account of or based upon any injury to person, or
                        loss of or damage to property, sustained on or occurring
                        elsewhere (other than on the Premises) in or about the
                        Property (and, in particular, without limitation, the
                        elevators, stairways, public corridors, sidewalks,
                        parking areas, concourses, arcades, approaches,
                        areaways, roof, or other appurtenances and facilities
                        used in connection with the Property or the Premises)
                        arising out of the use or occupancy of the Property or
                        Premises by the LESSEE or by any person claiming by,
                        through or under LESSEE, except where such injury, loss
                        or damage was caused by the negligence, fault or
                        misconduct of LESSOR, its agents, officers or employees;

                        and in addition to and not in limitation of either of
                        the foregoing subdivisions (i) and (ii);

                  (iii) on account of or based upon (including moneys due on
                        account of) any work or thing whatsoever done (other
                        than by LESSOR or its contractors, or agents or
                        employees or either) on the Premises; and, in respect of
                        any of the foregoing, from and against all costs,
                        expenses (including reasonable attorneys' fees), and
                        liabilities incurred in or in connection with any such
                        claim, or any action or proceeding brought thereon; and
                        in case any action or proceeding be brought against
                        LESSOR by reason of any such claim. LESSEE upon notice
                        from LESSOR shall at LESSEE'S expense resist or defend
                        such action or proceeding and employ counsel therefore
                        reasonably satisfactory to LESSOR, it being agreed that
                        such counsel as may act for insurance underwriters of
                        LESSEE engaged in such defense shall be deemed
                        satisfactory.

17.   LIABILITY   A. LESSEE'S Liability Insurance. The LESSEE shall maintain
      INSURANCE   with respect to the Premises and the Property of which the
                  Premises are a part commercial general liability insurance in
                  the amount of $1,000,000 with property damage insurance in
                  limits of $100,000 and Workers Compensation insurance insuring
                  against and satisfying LESSEE'S obligations and liabilities
                  under the Workers Compensation Laws of Massachusetts, in
                  responsible companies qualified to do business in
                  Massachusetts and in good standing therein insuring the LESSOR
                  as well as LESSEE against injury to persons or damage to
                  property as provided. LESSEE agrees to increase limits as
                  LESSOR'S mortgagee reasonably requires. The LESSEE shall
                  deposit with the LESSOR certificates for such insurance at or
                  prior to the commencement of the Term, and thereafter within
                  thirty (30) days prior to the expiration of any such policies.
                  All such insurance certificates shall provide that such
                  policies shall not be canceled without at least ten (10) days
                  prior written notice to each assured named therein.


                                        8

<PAGE>

                  B. LESSOR'S Liability Insurance. LESSOR covenants that it
                  shall maintain throughout the Term of this lease(i)
                  comprehensive general liability insurance against all claims
                  and demands for any injury to person or property which may be
                  claimed to have occurred on the Property in such amounts as
                  are commercially reasonable in the greater Boston,
                  Massachusetts area; and (ii) all risk property insurance.

18.   FIRE,       Should a substantial portion of the Premises, or of the
      CASUALTY,   property of which they are a part, be substantially damaged by
      EMINENT     fire or other casualty, or be taken by eminent domain, the
      DOMAIN      LESSOR may elect to terminate this lease. When such fire,
                  casualty, or taking renders the Premises substantially
                  unsuitable for its intended use, a just and proportionate
                  abatement of rent shall be made, and the LESSEE may elect to
                  terminate this lease if:

                  (a)   The LESSOR fails to give written notice within thirty
                        (30) days of the event of its intention to restore
                        Premises, or

                  (b)   The LESSOR fails to restore the Premises to a condition
                        substantially suitable for their intended use within
                        ninety (90) days of said fire, casualty or taking, as
                        such date may be extended ninety (90) days if LESSOR is
                        diligently working to restore the Premises and extended
                        an additional ninety (90) days for force majeure. LESSOR
                        reserves, and the LESSEE grants the LESSOR, all rights
                        which the LESSEE may have for damages or injury to the
                        Premises for any taking by eminent domain, except for
                        damage to the LESSEE'S fixtures, property, or equipment.

19.   DEFAULT     A)    In the event that:
      AND
      BANKRUPTCY        (i)   The LESSEE shall default in the payment of any
                              installment of rent or other sum herein specified
                              and such default shall continue for five (5) days
                              after written notice thereof; or

                        (ii)  The LESSEE shall default in the observance or
                              performance of any other of the LESSEE'S
                              covenants, agreements, or obligations hereunder
                              and such default shall not be corrected within
                              fifteen (15) days after written notice thereof, as
                              extended if LESSEE is working diligently and
                              continuously to cure; or

                        (iii) The LESSEE or any guarantor of LESSEE'S
                              obligations under the lease, files or is filed
                              against in any bankruptcy, insolvency or
                              reorganization petition; or

                        (iv)  The LESSEE shall be declared bankrupt or insolvent
                              according to law, or, if any assignment shall be
                              made of LESSEE'S property for the benefit of
                              creditors, or

                        (v)   Any attachment is made of the leasehold interest
                              outlined in this lease which is not removed within
                              sixty (60) days; or

                        (vi)  A receiver is appointed to conduct LESSEE'S
                              business (whether or not LESSOR has re-entered the
                              premises) then the LESSOR shall have the right
                              thereafter, while such default continues, to
                              re-enter and take complete possession of the
                              Premises, to terminate this lease, and remove the
                              LESSEE'S effects without prejudice to any remedies
                              which might be otherwise used for arrears of rent
                              or other default. The LESSEE shall indemnify the
                              LESSOR against all loss of rent and additional
                              rent and other payments which the LESSOR may incur
                              by reason of such termination during the residue
                              of the


                                        9
<PAGE>

                              term. If the LESSEE shall default, after
                              reasonable notice thereof; in the observance or
                              performance of any conditions or covenants on
                              LESSEE'S part to be observed or performed under or
                              by virtue of any of the provisions in any article
                              of this lease, the LESSOR, without being under any
                              obligation to do so and without thereby waiving
                              such default, may remedy such default for the
                              account and at the expense of the LESSEE. If the
                              LESSOR makes any expenditures or incurs any
                              obligations for the payment of money in connection
                              therewith, including but not limited to,
                              reasonable attorney's fees in instituting,
                              prosecuting or defending any action or proceeding,
                              such sums paid or obligations incurred, with
                              interest at the rate of 18 per cent per annum and
                              costs, shall be paid to the LESSOR by the LESSEE
                              as additional rent. Any sums not paid when due
                              shall bear interest at 18 per cent per annum until
                              paid. LESSEE shall pay an administrative fee if a
                              check does not clear.

                  B)    LESSOR'S REMEDIES. If any one or more events of default
                        set forth above occurs, LESSOR may, at its election:

                        (i)   Give LESSEE written notice of LESSOR'S intention
                              to terminate this Lease on the earliest date
                              permitted by law or on any later date specified in
                              such notice, in which case LESSEE'S right to
                              possession of the Premises will cease and this
                              Lease will be terminated, except as to LESSEE'S
                              liability, as if the expiration of the term fixed
                              in such notice were the end of the Term;

                        (ii)  Without further demand or notice, and without
                              terminating this Lease, reenter and take
                              possession of the Premises or any part of the
                              Premises, repossess the same, expel LESSEE and
                              those claiming through or under LESSEE and remove
                              the effects of both or either, using such force
                              for such purposes as may be necessary, without
                              being liable for prosecution, without being deemed
                              guilty of any matter of trespass, and without
                              prejudice to any remedies for arrears of Monthly
                              Rent or other amounts payable under this Lease or
                              as a result of any preceding breach of covenants
                              or conditions; or

                        (iii) Without further demand or notice to cure any event
                              of default and charge LESSEE for the cost of
                              effecting such cure, including without limitation
                              reasonable attorneys' fees and interest on the
                              amount of 18 percent per annum, provided that
                              LESSOR will have no obligation to cure any such
                              event of default of LESSEE.

                  If LESSOR elects to reenter as provided in subsection (ii) or
                  if LESSOR takes possession pursuant to legal proceedings or
                  pursuant to any notice provided by law, LESSOR may, from time
                  to time, without terminating this Lease, relet the Premises or
                  any part of the Premises in LESSOR'S or LESSEE'S name, but for
                  the account of LESSEE, for such term or terms (which may be
                  greater or less than the period which would otherwise have
                  constituted the balance of the Term) and on such conditions
                  and upon such other terms (which may include concessions of
                  free rent and alteration and repair of the Premises) as
                  LESSOR, in its reasonable discretion, may determine, and
                  LESSOR may collect and receive the rents from such reletting.
                  LESSOR will in no way be responsible or liable for any failure
                  to relet the Premises, or any part of the Premises, or for any
                  failure to collect any rent due upon such reletting. No such
                  reentry or taking possession of the Premises by LESSOR will be
                  construed as an election on LESSOR'S part to terminate this
                  Lease unless a written notice of such intention is given to
                  LESSEE. No written notice from LESSOR under this Section or
                  under a forcible or unlawful entry and detainer statute or
                  similar law will constitute an election by LESSOR to terminate
                  this Lease unless such notice specifically so states. LESSOR
                  reserves the right following any such reentry or reletting to
                  exercise its right


                                       10
<PAGE>

                  to terminate this Lease by giving LESSEE such written notice,
                  in which event this Lease will terminate as specified in such
                  notice. LESSOR shall use reasonable efforts to relet the
                  Premises.

20.   NOTICE      Any Notice from the LESSOR to the LESSEE relating to the
                  Premises or to the occupancy thereof, shall be in writing and
                  be deemed duly served, if mailed to the Notice Address in
                  Section 1 of this Lease, or other such address as LESSEE may,
                  from time to time, advise in writing, registered or certified
                  mail, return receipt requested, postage prepaid or by
                  overnight carrier, addressed to the LESSEE. Any Notice from
                  the LESSEE to the LESSOR relating to the Premises or to the
                  occupancy thereof, shall be deemed duly served, if mailed to
                  the LESSOR by registered or certified mail, return receipt
                  requested, postage prepaid or by overnight carrier, addressed
                  to the LESSOR at the address in Section 1 of this Lease or
                  such other address as the LESSOR may from time to time advise
                  in writing. All rent notices shall be paid and sent to the
                  LESSOR at its notice address or such other address as may be
                  designated by LESSOR. All notices shall be effective when
                  received or refused.

21.   SURRENDER   The LESSEE shall at the expiration or other termination of
                  this Lease remove all LESSEE'S goods and effects from the
                  Premises, (including, without hereby limiting the generality
                  of the foregoing, all signs and lettering affixed or painted
                  by the LESSEE, either inside or outside the Premises). LESSEE
                  shall deliver to the LESSOR the Premises and all keys, locks
                  thereto, and other fixtures connected therewith and all
                  alterations and additions made to or upon the Premises, in
                  good condition, reasonable wear and tear and, damage by fire
                  or other casualty only excepted. In the event of the LESSEE'S
                  failure to remove any of LESSEE'S property from the Premises,
                  LESSOR is hereby authorized, without liability to LESSEE for
                  loss or damage thereto, and at the sole risk of LESSEE, to
                  remove and store any of the property at LESSEE'S expense, or
                  to retain same under LESSOR'S control or to sell at public or
                  private sale, without notice any or all of the property not so
                  removed and to apply the net proceeds of such sale to the
                  payment of any sum due hereunder, or to destroy such property.
                  The LESSEE shall restore all damage to the Premises which may
                  have occurred during the use of Premises or while vacating the
                  Premises. Any items which the LESSEE installs, which replace
                  items on the Premises when LESSEE took occupancy are deemed to
                  be LESSOR'S property.

22.   BROKERAGE   LESSEE warrants and represents that LESSEE has dealt with no
                  broker other than the broker listed in Section 1 of this lease
                  in connection with the consummation of this Lease and, in the
                  event of any brokerage claims against LESSOR predicated upon
                  prior dealings with LESSEE, LESSEE agrees to defend the same
                  and indemnify LESSOR against any such claim.

23.   LESSOR'S    The LESSOR is not personally liable under this
      LIABILITY   Lease. (a) LESSEE specifically agrees to look solely to the
                  LESSOR'S then equity in the property of which the Premises are
                  a part (and to proceeds thereof) for recovery of any judgment
                  from LESSOR it being specifically agreed that LESSOR (original
                  or successor) shall never be personally liable for any such
                  judgment or for the payment of any monetary obligation to
                  LESSEE. The provisions contained in the foregoing sentence are
                  not intended to, and shall not, limit any right the LESSEE
                  might otherwise have to obtain injunctive relief against
                  LESSOR or to take any action not involving the liability of
                  LESSOR to respond in monetary damages from LESSOR'S assets
                  other than from such property.

24.   WAIVER      Failure on the part of the LESSOR or LESSEE to complain of any
                  action or non-action on the part of the other, no matter how
                  long the same may continue, shall never be a waiver by LESSOR
                  or LESSEE, respectively, of its rights hereunder. Further, no


                                       11

<PAGE>

                  waiver at any time of the provisions hereof, by LESSOR or
                  LESSEE shall be construed as a waiver of any of the other
                  provisions hereof, and a waiver at any time of any of the
                  provisions hereof shall not be construed as a waiver at any
                  subsequent time of the same provisions. The consent or
                  approval of LESSOR or LESSEE to, or of any action by the other
                  requiring such consent or approval, shall not be construed to
                  waive or render unnecessary LESSOR'S or LESSEE'S consent or
                  approval to or of any subsequent similar act by the other.

25.   STATUS      Recognizing that both parties may find it necessary to
      REPORT      establish to third parties, from time to time, the then
                  current status of performance hereunder, either party will,
                  within ten (10) days after receipt of a request therefor,
                  furnish a reasonable statement of the status of this Lease,
                  including without limitation, acknowledgments that (or the
                  extent to which) each party is in compliance with its
                  obligations under the terms of the Lease.

26.   BUILDOUT    Except as specifically provided herein, LESSEE shall accept
                  possession of Premises in "As Is" condition. Except as
                  specifically provided below, LESSOR has no obligation and has
                  made no promise to alter, remodel, improve, repair, decorate
                  or paint the Premises or any part of the Premises, or to pay
                  for such work, and LESSOR has not made any representations to
                  LESSEE with respect to the condition of the Premises.

            A.    PLANS    LESSEE shall cause its architect (the "Architect") to
                           prepare (consistent with the building specifications
                           or standards) and submit to LESSOR for its approval
                           complete architectural plans, drawings and
                           specifications for all LESSOR'S Work (defined below),
                           including, without limitation, complete engineered
                           mechanical and electrical working drawings for the
                           premises, showing the subdivision, layout, finish and
                           decoration work desired by LESSEE therefore, and any
                           internal or external communications or special
                           utility facilities which will require installation of
                           conduits or other improvements within common areas,
                           all in such form and in such detail as my be required
                           by LESSOR. Such complete plans, drawings and
                           specifications are referred to herein as "Final
                           Plans". LESSEE shall submit the Final Plans for the
                           approval of LESSOR, and such final plan shall be
                           delivered to LESSOR no later than April 21, 2000.
                           Within five (5) business days after LESSOR receives
                           the Final Plans for approval, LESSOR shall give its
                           written approval of the Final Plans, or provide
                           LESSEE with specific written objections to the Final
                           Plans. If LESSOR does not respond within such five
                           (5) business day period, LESSOR shall be deemed to
                           have approved the Final Plans on the fifth business
                           day of such period. If LESSOR objects to the Final
                           Plans LESSEE and LESSOR shall meet within three (3)
                           business days after said objection to resolve the
                           objections and to deliver to Architect such
                           information as may be necessary to enable Architect
                           to cause the Final Plans to be revised consistent
                           with LESSOR'S objections. The day on which LESSOR
                           approves, or is deemed to have approved, the Final
                           Plans, shall be hereinafter referred to as the
                           "Approval Date".

            B.    SCHEDULE Based on the Final Plans and on or before the
                           Approval Date, the Architect and LESSOR'S
                           representatives shall reasonably agree on the number
                           of days within which the LESSEE Improvement Work
                           should be substantially complete if pursued with
                           commercially reasonable diligence (the "Scheduled
                           Completion Period").

            C.    WORK     LESSOR shall construct the tenant improvements
                           ("LESSOR'S Work") LESSOR shall pay an amount not to
                           exceed Three Hundred Three Thousand Seven Hundred
                           Twenty and No/100 Dollars ($303,720.00), which sum


                                       12


<PAGE>


                           of completing the space planning, working drawings,
                           engineering, permits, architect's fees and other fees
                           and LESSOR'S Work (the "LESSOR'S Contribution"), and
                           LESSEE shall pay for all costs of completing the
                           LESSOR'S Work in excess of LESSOR'S Contribution
                           ("LESSEE'S Contribution"). LESSEE'S Contribution
                           shall be paid to LESSOR prior to the Commencement of
                           LESSOR'S Work. And, LESSEE shall provide payment for
                           any change orders at the time of LESSEE'S approval of
                           each change order.

            D.    LESSEE   To the extent LESSEE delays in delivering the Final
                  DELAY    Plans to LESSOR as set forth in Section A above, the
                           Commencement Date shall be moved up one day for each
                           such day of delay by LESSEE.

                           i) Any change by LESSEE in any of the Final Plans
                           after LESSEE'S approval thereof:

                           ii) Any other act or omission of LESSEE or its
                           officers, agents, servants or contractors:

                           iii) Any reasonably necessary displacement of any of
                           LESSOR'S Work from its place in LESSOR'S construction
                           schedule resulting from any of the causes for delay
                           referred to in clauses (i), (ii), or this paragraph
                           and the fitting of such Work back into such schedule;
                           then LESSEE shall, from time to time and within ten
                           (10) business days after demand therefor, pay to
                           LESSOR for each day of such delay the amount of Basic
                           Rent, Escalation Charges and other charges that would
                           have been payable hereunder and the LESSEE'S
                           obligation to pay Basic Rent commenced immediately
                           prior to such delay.

            E.    LESSOR   If the LESSOR'S Work is not complete by the Scheduled
                  DELAY    Completion Date, the LESSEE shall be allowed to
                           remain in the Temporary Premises and pay rent on only
                           the Temporary Premises until such time as the
                           Premises are substantially complete. Substantial
                           completion shall be deemed to have occurred when the
                           Architect and LESSOR'S representative reasonably
                           agree that the only remaining LESSOR'S Work to be
                           completed are minor, so-called punch list items.
                           LESSEE shall have the right to remain in the
                           Temporary Premises until seven (7) days after
                           substantial completion of the LESSOR'S Work.

                           The delays referred to above are herein referred to
                           collectively and individually as "LESSEE'S Delay."

            F.    CONCLUSIVE-
                  NESS OF
                  PERFORM- Except to the extent to which LESSEE shall have given
                  ANCE     LESSOR notice, not later than the end of the second
                           full calendar month beginning after substantial
                           completion of the LESSOR'S Work, of any respects in
                           which LESSOR has not performed LESSOR'S Work, LESSOR
                           shall be deemed to have completed the LESSOR'S Work
                           as of such substantial completion date.

27.   LESSOR'S    LESSOR warrants and represents that it is the owner of record
      WARRANTY    of the Premises and that it has authority to grant the
                  leasehold interest conveyed hereby.

28.   SEVERABIL-  To the extent any term or provision of this Lease, or the
      ITY         application thereof to any person or circumstance shall be
                  invalid or unenforceable, the remainder of this Lease,


                                       13


<PAGE>

                  or the application of such term or provision to persons or
                  circumstances other than those as to which it is held invalid
                  or unenforceable, shall not be affected thereby, and each term
                  and provision of this Lease shall be valid and be enforced to
                  the fullest extent permitted by law.

29.   RECORDING   LESSEE agrees not to record this Lease, but, if the Term of
                  this Lease (including any extended term) is seven (7) years or
                  longer, each party hereto agrees, on the request of the other,
                  to execute a so-called Notice of Lease in recordable form and
                  complying with applicable law and reasonably satisfactory to
                  LESSOR'S and LESSEE'S attorneys. Such document shall expressly
                  state that it is executed pursuant to the provisions contained
                  in this Lease, and is not intended to vary the terms and
                  conditions of this Lease.

30.   HOLDING     Any Holding Over by LESSEE after the expiration of the Term of
      OVER        this Lease shall be treated as a tenancy at sufferance at a
                  rate equal to one and one-half times the Basic Rent then in
                  effect plus Additional Rent and other charges herein provided.
                  LESSEE shall also pay to LESSOR all direct damages sustained
                  by reason of any such holding over. Otherwise, such Holding
                  Over shall be on the terms and conditions set forth in this
                  Lease as far as applicable.

31.   GOVERNING   This Lease shall be governed exclusively by the provisions
      LAW         hereof and by the laws of the Commonwealth of Massachusetts,
                  as the same may from time to time exist. No amendment,
                  alteration, modification of, or addition to the Lease will be
                  valid or binding unless expressed in writing and signed by
                  LESSOR and LESSEE. LESSEE agrees to make any modifications of
                  the terms and provisions of this Lease required and requested
                  by any lending institution providing financing for the
                  Building, or Project, as the case may be, provided that no
                  such modifications will materially adversely affect LESSEE'S
                  rights and obligations under this Lease.

32.   RELOCATION  Deleted.

33.   ENTIRE      This Lease and the Exhibits made a part hereof contain the
      AGREEMENT   entire and only agreement between the parties and any and all
                  statements and representations, written and oral, including
                  previous correspondence and agreements between the parties
                  hereto, are merged herein. LESSEE acknowledges that all
                  representations and statements upon which it relied in
                  executing this Lease are contained herein and that the LESSEE
                  in no way relied upon any other statements or representations,
                  written or oral. Any executory agreement hereafter made shall
                  be ineffective to change, modify, discharge or effect an
                  abandonment of this Lease in whole or in part unless such
                  executory agreement is in writing and signed by the party
                  against whom enforcement of the change, modification,
                  discharge or abandonment is sought.

34.   RULES &
      REGULATIONS
                  LESSEE, its employees, agents, licensees, and visitors will at
                  all times, observe faithfully, and comply strictly with, the
                  Rules and Regulations set forth in Exhibit E. LESSOR may from
                  time to time reasonably amend, delete, or modify existing
                  Rules and Regulations, or adopt reasonable new Rules and
                  Regulations for the use, safety, cleanliness, and care of the
                  Premises and the Property, and the comfort, quiet, and
                  convenience of occupants of the Property. Modifications or
                  additions to the Rules and Regulations will be effective upon
                  thirty (30) days' prior written notice to LESSEE from LESSOR.
                  In the event of any breach of any Rules or Regulations or any
                  amendments or additions to such Rules and Regulations, LESSOR
                  will have all remedies that this Lease provides for default by
                  LESSOR, and will in addition have


                                       14

<PAGE>

                  any remedies available at law or in equity, including the
                  right to enjoin any breach of such Rules and Regulations.
                  LESSOR will not be liable to LESSEE for violation of such
                  Rules and Regulations by any other tenant, its employees,
                  agents, visitors, or licensees or any other person. In the
                  event of any conflict between the provisions of this Lease and
                  the Rules and Regulations, the provisions of this Lease will
                  govern.

35.   OPTION TO   Provided that at the time of such exercise (i) there then
      EXTEND      exists no Default of LESSEE, (ii) this Lease is then in full
                  force and effect, and (iii) LESSEE is in actual occupancy of
                  all or substantially all of the Premises, LESSEE shall have
                  the right and option to extend the term of this Lease for one
                  (1) extended term of five years (the "Extended Term"). The
                  Extended Term shall commence on the day immediately succeeding
                  the expiration date of the Initial Term, and shall end on the
                  day immediately preceding the fifth anniversary of the first
                  day of such Extended Term. LESSEE shall exercise such option
                  to extend by giving written notice to LESSOR of its desire to
                  do so not earlier than twelve (12) months and not later than
                  nine (9) months prior to the expiration date of the Initial
                  Term. Provided the conditions of clauses (i), (ii) and (iii)
                  of this section shall have been satisfied, the giving of such
                  notice by LESSEE shall automatically extend the Term of this
                  Lease for the Extended Term, and no instrument of renewal need
                  be executed. In the event that LESSEE fails to give such
                  notice to LESSOR, this Lease shall automatically terminate at
                  the end of the Initial Term, and LESSEE shall have no further
                  option to extend the Term of this Lease. It is agreed that
                  time is of the essence with respect to the giving of such
                  notice. The Extended Term shall be on all the terms and
                  conditions of this Lease, except that (I) option to extend
                  that Term of this Lease shall be deleted, and (II) the Basic
                  Rent for the Extended Term shall be at Fair Market Value, not
                  less than the sum of the rent and all additional rent being
                  paid by LESSEE during the final year of the Initial Term.
                  LESSOR shall designate Fair Market Value, (the "Fair Market
                  Value") by written notice to LESSEE within sixty (60) days of
                  receipt of notice from LESSEE. If LESSEE disagrees with such
                  designation, (the "Designation"), LESSEE shall by written
                  notice within thirty (30) days after receipt of LESSOR'S
                  figure, advise LESSOR of such disagreement; otherwise LESSEE
                  shall conclusively be deemed to have agreed to such
                  Designation.

                  In the event that the Parties are unable to agree, each Party
                  shall appoint an appraiser. Each appraiser so appointed shall
                  be instructed to determine independently the Fair Market Value
                  and then confer. If the two appraisers are unable to determine
                  a Designation acceptable to both parties, they shall appoint a
                  third appraiser. The Designation of this appraiser shall be
                  considered final.


                                       15

<PAGE>

36.   TEMPORARY   LESSEE may occupy the Temporary Premises (the "Temporary
      TENANCY     Tenancy") under the same terms and conditions as the Premises
                  from March 6, 2000 until substantial completion of the
                  Premises except that the Basic Rent shall be $25,037.82 per
                  month, pro-rated for any partial month and there shall be no
                  Additional Rent due for the Temporary Tenancy and the Term
                  shall be extended for the Temporary Tenancy.

37.   RIGHT OF
      FIRST       If at any time during the Term of this Lease of this Lease,
      OFFER       LESSOR shall desire to Lease Suite 550 consisting of 7,272
                  rentable square feet on the fifth floor of the Building or
                  Suite 530 consisting of 3,364 rentable square feet on the
                  fifth floor of the Building as described in Exhibit G1
                  attached hereto or LESSOR shall desire to lease Suite 1000
                  consisting of 22,664 rentable square feet on the tenth floor
                  of the Building as described in Exhibit G2, attached hereto,
                  (the "First Offer Space"), LESSOR shall notify LESSEE and set
                  forth the terms and conditions on which LESSOR is willing to
                  lease the First Offer Space, including, without limitation,
                  rent, build-out allowance and other incentives or inducements
                  to lease, if any. LESSEE acknowledges that LESSOR has granted
                  this Right of First Offer for Suite 1000 to the Yankee Group
                  prior to the Execution of this Lease. Provided that the time
                  of such exercise (i) there then exists no Default of LESSEE,
                  (ii) this Lease is then if full force and effect, and (iii)
                  LESSEE is in actual occupancy of the entire Premises demised
                  thereunder, LESSEE may, by giving notice in writing to LESSOR
                  within three (3) Business Days after receipt of LESSOR'S
                  notice, elect to lease the First Offer Space on the terms so
                  offered by LESSOR. If LESSEE shall so elect to lease the First
                  Offer Space, it shall within seven (7) days after such
                  election enter into an amendment to this Lease incorporating
                  the terms and contained in LESSOR'S notice. If LESSEE shall
                  not elect to lease the First Offer Space within such three (3)
                  Business Day period, or shall fail to enter into such
                  amendment to this Lease within such seven-day period, LESSEE
                  shall have no further rights under this section with respect
                  to the First Offer Space and LESSOR shall be free to lease any
                  or all of such space to other parties.

IN WITNESS WHEREOF, the said parties hereunto set their hands and seals as of
the date above.

LESSEE: PaperExchange.com, LLC    LESSOR: OMV Associates Limited Partnership
                                      BY: Park Square Corporation - its General
                                          Partner
                                      BY: Richard D. Cohen - its President

BY:_________________________


____________________________              _________________________________

Hereunto Duly Authorized

<PAGE>

                                    Premises

Not to Scale                                                  Capital Properties
                                                                  February, 1998

                               [GRAPHIC OMITTED]

                                                       Fifth Floor Stacking Plan
                                                        The Park Square Building

                         Winter Street Architects, Inc.

<PAGE>

                                    EXHIBIT B

                          Legal Description of the Land

All that certain lot, piece or parcel of land situated, lying and being in the
City of Boston, Suffolk County, Massachusetts. with the buildings thereon,
bounded and described as follows:

NORTHERLY:  by Providence Street, six hundred seven and 40/100 (607.40) feet.

EASTERLY:   by Arlington Street, seventy-five and 06/100 (75.06) feet,

SOUTHERLY:  by St. James Avenue, six hundred four and 31/100 (604.31) feet and

WESTERLY:   by Berkeley Street, seventy-five (75) feet

containing 45,439 square feet, more or less and being the same premises conveyed
by deed dated April 30, 1981 and recorded with Suffolk County Registry of Deeds,
Book 9741, Page 184.


                                       18

<PAGE>

                                    EXHIBIT C

                      ITEMS INCLUDED IN OPERATING EXPENSES

Without limitation, Operating Expenses shall include:

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

2.    The cost of services, utilities, materials and supplies furnished or used
      in the operation, repair, maintenance, including without limitation fees,
      if any, imposed upon Lessor, or charged to the Property, by the state or
      municipality in which the Property is located on account of the need of
      the Property for increased or augmented public safety services.

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

4.    Where the Property is managed by Lessor or an affiliate of Lessor, a sum
      equal to the amounts customarily charged by management firms in the
      Boston/Brookline area for similar properties, but in no event more than
      five (5%) percent of gross annual income, whether or not actually paid, or
      where managed by other than Lessor or an affiliate thereof, the amounts
      charged for management, together with, in either case, reasonable amounts
      charged for legal and other professional fees relating to the Property,
      but excluding such fees and commissions paid in connection with services
      rendered for securing, terminating or renewing leases and administration
      and operation of the Premises.

5.    Reasonable premiums for insurance against damage or loss to the Property
      from such hazards as shall from time to time be required by mortgagees.

6.    If, during the Term of this Lease, Lessor shall make a capital
      expenditure, the total cost of which is not properly includable in
      Operating Expenses for the Operating Year in which it was made, there
      shall nevertheless be included in such Operating Expenses for the
      Operating Year in which it was made and in Operating Expenses for each
      succeeding Operating Year the annual charge-off of such capital
      expenditure; and the useful life shall be determined reasonably by Lessor
      in accordance with generally accepted accounting principles and practices
      in effect at the time of making such expenditure.

7.    Costs for electricity, water and sewer use charges, and other utilities
      supplied to the Property and not paid for directly by Lessees.

8.    Betterment assessments provided the same are apportioned equally over the
      longest period permitted by law, and any other governmental charges or
      taxes not included in Taxes, including linkage payments, if any.

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


                                       19


<PAGE>


10.   The following items shall be excluded from the Operating Expenses:

            o     Electricity which is billed directly to LESSEE or any Tenant
                  in the Building.

            o     Mortgage Charges

            o     Brokerage commissions

            o     Cost of work done by LESSOR for a particular tenant for which
                  LESSOR has the right to be reimbursed by such tenant.


                                       20

<PAGE>

                                    Exhibit D
                               Temporary Premises

Not to Scale                                                  Capital Properties
                                                                  February, 1998

                               [GRAPHIC OMITTED]

                                                       Third Floor Stacking Plan
                                                        The Park Square Building

                         Winter Street Architects, Inc.

<PAGE>

                                    EXHIBIT E

                               Rules & Regulations

      1. LESSOR may from time to time adopt appropriate systems and procedures
for the security or safety of the Building, any persons occupying, using or
entering the Building, or any equipment, finishings, or contents of the
Building, and LESSEE will comply with LESSOR'S requirements relative to such
systems and procedures, provided the foregoing shall not impair LESSEE'S right
to have access to the Premises twenty-four hours per day, seven days per week,
fifty-two weeks per year.

      2. The sidewalks, halls, passages, exits, entrances, elevators, and
stairways of the Building will not be obstructed by any tenant or used for any
purpose other than for ingress to and egress from the Building. The halls,
passages, exits, entrances, elevators, escalators, and stairways are not for the
general public, and LESSOR will in all cases retain the right to control and
prevent access to such halls, passages, exits, entrances, elevators, and
stairways of all persons whose presence in the judgment of LESSOR would be
prejudicial to the safety, character, reputation, and interests of the Building
and its tenants, provided that nothing contained in these rules and regulations
will be construed to prevent such access to persons with whom any tenant
normally deals in the ordinary course of its business, unless such persons are
engaged in illegal activities. No lessee and no employee or invitee of any
tenant will go upon the roof of the Building except such roof or portion of such
roof as may be contiguous to a Premises of a particular tenant and may be
designated in writing by LESSOR as a roof deck or roof garden area. No tenant
will be permitted to place or install any object (including without limitation
radio and television antennas, loudspeakers, sound amplifiers, microwave dishes,
solar devices, or similar devices) on the exterior of the Building or on the
roof of the Building.

      3. No sign, placard, picture, name advertisement, or written notice
visible from the exterior of LESSEE'S Premises will be inscribed, painted,
affixed, or otherwise displayed by LESSEE on any part of the Building or the
Premises without the prior written consent of LESSOR, other than signs approved
per this Lease. LESSOR will adopt and furnish to LESSEE general guidelines
relating to signs inside the Building on the office floors. LESSEE agrees to
conform to such guidelines. All approved signs or lettering on doors will be
printed, painted, affixed, or inscribed at the expense of the LESSEE by a person
approved by LESSOR. Other than window treatments expressly permitted by LESSOR
and building standard window treatments, material visible from outside the
Building will not be permitted. In the event of the violation of this rule by
LESSEE, LESSOR may remove the violating items without any liability, and may
charge the expenses incurred by such removal to the tenants or tenants violating
this rules.

      4. No cooking will be done or permitted by any LESSEE on the Premises,
except in areas of the Premises which are specially constructed for cooking and
except that use by LESSEE of microwave ovens and Underwriters' Laboratory
approved equipment for brewing coffee, tea, hot chocolate, and similar beverages
will be permitted, provided that such use is in accordance with all applicable
federal, state and city laws, codes, ordinances, rules and regulations.

      5. No LESSEE will employ any person or persons other than the cleaning
service of LESSOR for the purpose of cleaning the Premises, unless otherwise
agreed to by LESSOR in writing. Except with the written consent of LESSOR, no
person or persons other than those approved by LESSOR will be permitted to enter
the Building for the purpose of cleaning it. No LESSEE will cause any
unnecessary labor by reason of such LESSEE'S carelessness or indifference in the
preservation of good order and cleanliness. Should LESSEE'S actions result in
any increased expenses for any required cleaning, LESSOR reserves the right to
assess LESSEE for such expenses.

      6. The toilet rooms, toilets, urinals, wash bowls and other plumbing
fixtures will not be used for any purposes other than those for which they were
constructed, and no sweepings, rubbish, rags, or other foreign substances will
be thrown in such plumbing fixtures. All damages resulting from any misuse of
the fixtures will be borne by the tenant who, or whose servants, employees,
agents, visitors, or licensees, caused the same.


                                       22


<PAGE>


      7. No LESSEE, or LESSEE'S invitees or licensees, will in any way deface
any part of the Premises or the Building of which they form a part. in those
portions of the Premises where carpet has been provided directly or indirectly
by LESSOR, LESSEE will at its own expense install and maintain pads to protect
the carpet under all furniture having casters other than carpet casters.

      8. No LESSEE will alter, change, replace, or rekey any lock or install a
new lock or a knocker on any door of the Premises. LESSOR, its agents, or
employees will retain a pass (master) key to all door locks on the Premises. Any
new door locks required by LESSEE or any change in keying of existing locks will
be installed or changed by LESSOR following tenant's written request to LESSOR
and will be at LESSEE'S expense. all new locks and rekeyed locks will remain
operable by LESSOR'S pass (master) key. LESSOR will furnish each tenant, free of
charge, with two (2) keys to each suite entry door lock on the Premises. LESSOR
will have the right to collect a reasonable charge for additional keys and cards
requested by any tenant. Each tenant, upon termination of its tenancy, will
deliver to LESSOR all keys and access cards for the Premises and Building that
have been furnished to such tenant.

      9. The elevator designated for freight by LESSOR will be available for use
by all tenants in the Building during the hours and pursuant to such procedures
as LESSOR may determine from time to time. The persons employed to move LESSEE'S
equipment, material, furniture, or other property in or out of the Building must
be acceptable to LESSOR. The moving company must be a locally recognized
professional mover, whose primary business is performing of relocation services,
and must be bonded and fully insured. A certificate or other verification of
such insurance must be received and approved by LESSOR prior to the start of any
moving operations. Insurance must be sufficient, in LESSOR'S sole opinion, to
cover all personal liability, theft or damage to the Project, including but not
limited to floor coverings, doors, walls, elevators, stairs, foliage, and
landscaping. Special care must be taken to prevent damage to foliage and
landscaping during adverse weather. All moving operations will be conducted at
such times and in such a manner as LESSOR will direct, and all moving will take
place during non-Business Hours unless LESSOR agrees in writing otherwise.
LESSEE will be responsible for the provision of building security during all
moving operations, and will be liable for all losses and damages sustained by
any party as a result of the failure to supply adequate security. LESSOR will
have the right to prescribe the weight, size, and position of all equipment,
materials, furniture, or other property brought into the Building. Heavy objects
will, if considered necessary by LESSOR, stand on wood strips of such thickness
as is necessary to property distribute the weight. LESSOR will not be
responsible for loss of or damage to any such property from any cause, and all
damage done to the building by moving or maintaining such property will be
repaired at the expense of LESSEE. LESSOR reserves the right to inspect all such
property to be brought into the building and to exclude from the Building all
such property which violates any of these rules and regulations or the Lease of
which these rules and regulations are a part. Supplies, goods, materials,
packages, furniture, and all other items of every kind delivered to or taken
from the Premises will be delivered or removed through the entrance and route
designated by LESSOR, and LESSOR will not be responsible for the loss or damage
of any such property.

      10. No lessee will use or keep in the Premises or the building any
kerosene, gasoline, or inflammable or combustible or explosive fluid or material
or chemical substance other than limited quantities of such materials or
substances reasonably necessary for the operation or maintenance of office
equipment or limited quantities of cleaning fluids and solvents required in
lessee's normal operations in the Premises, which shall be stored in accordance
with applicable law. Without LESSOR'S prior written approval, no lessee will use
any method of heating or air conditioning other than that supplied by LESSOR. No
lessee will use or keep or permit to be used or kept any foul or noxious gas or
substance in the Premises.

      11. Lessees shall not , prior to or during the Term, either directly or
indirectly, employ or permit the employment of any contractor, mover, mechanic
or laborer, or permit any materials in the Premises, if the use of such
contractor, mover, mechanic or laborer or such materials would, in LESSOR'S
opinion, create any difficulty, strike or jurisdictional dispute with other
contractors, movers, mechanics or laborers engaged by LESSOR, lessee, or others,
or would in any way disturb the construction, maintenance, cleaning, repair,
management, security or operation of the Building, Project or any part thereof.
Any lessee, upon demand by LESSOR, shall cause all contractors, movers,
mechanics, laborers or materials causing such interference, difficulty or
conflict to leave or be removed from the Project immediately.


                                       23

<PAGE>

      12. LESSOR will have the right to prohibit any advertising by LESSEE
mentioning the Building, that in LESSOR'S reasonable opinion, tends to impair
the reputation of the Building or its desirability as a building for offices,
and upon written notice from LESSOR, LESSEE will refrain from or discontinue
such advertising.

      13. LESSEE will not bring any animals (except "Seeing Eye" dogs) or birds
into the building, and will not permit bicycles or other vehicles inside or on
the sidewalks outside the Building except in areas designated from time to time
by LESSOR for such purposes.

      14. All persons entering or leaving the building between the hours of 6
p.m. and 8 a.m. Monday through Friday, and at all hours on Saturdays, Sundays,
and holidays will comply with such off-hour regulations as LESSOR may establish
and modify from time to time. LESSOR reserves the right to limit reasonably or
restrict access to the Building during such time periods.

      15. Each lessee will store all its trash and garbage within its Premises.
No material will be placed in the trash boxes or receptacles if such material is
of such nature that it may not be disposed of in the ordinary and customary
manner of removing and disposing of trash and garbage without being in violation
of any law or ordinance governing such disposal. All garbage and refuse disposal
will be made only through entryways and elevators provided for such purposes and
at such times as LESSOR designates. Removal of any furniture or furnishings,
large equipment, packing crates, packing materials, and boxes will be the
responsibility of each lessee and such items may not be disposed of in the
Buildings trash receptacles nor will they be removed by the Building's
janitorial service, except at LESSOR'S sole option and at the lessee's expense.
No furniture, appliances, equipment, or flammable products of any type may be
disposed of in the Building trash receptacles.

      16. Canvassing, peddling, soliciting, and distributing handbills or any
other written materials in the Building are prohibited, and each lessee will
cooperate to prevent the same.

      17. The requirements of the lessee's will be attended to only upon
application by written, personal, or telephone notice at the office of the
Building. Employees of LESSOR or LESSOR'S agent will not perform any work or do
anything outside of their regular duties unless under special instructions from
LESSOR.

      18. A directory of the Building will be provided for the display of the
name and location of tenants only. all entries on the Building directory display
will conform to standards and style set by LESSOR in its sole discretion. Space
on any exterior signage will be provided in LESSOR'S sole discretion. No lessee
will have any right to the use of any exterior sign.

      19. LESSEE will see that the doors of the Premises are closed and locked
and that all water faucets, water apparatus, and utilities are shut off before
LESSEE or LESSEE'S employees leave the Premises, so as to prevent waste or
damage, and for any failure to comply or carelessness in this regard LESSEE will
make good all injuries sustained by other tenants or occupants of the Building
or LESSOR. On multiple-tenancy floors, all lessee's will keep the doors to the
Building corridors closed at all times except for ingress or egress.

      20. LESSEE will not conduct itself in any manner that is inconsistent with
the character of the building as a first quality building or that will impair
the comfort and convenience of other tenants in the Building.

      21. No act or thing done or omitted to be done by LESSOR or LESSOR'S agent
during the term of the Lease in connection with the enforcement of these rules
and regulations will constitute an eviction by LESSOR of any lessee nor will it
be deemed an acceptance of surrender of the Premises by any lessee, and no
agreement to accept such termination or surrender will be valid unless in a
writing signed by LESSOR. The delivery of keys to any employee or agent of
LESSOR will not operate as a termination of the Lease or a surrender of the
Premises unless such delivery of keys is done in connection with a written
instrument executed by LESSOR approving the termination or surrender.

      22. In these rules and regulations, the term "lessee" includes the
employees, agents, invitees, and licensees of LESSEE and others permitted by
LESSEE to use or occupy the Premises.


                                       24

<PAGE>

      23. LESSOR may waive any one or more of these rules and regulations for
the benefit of any particular lessee or lessees, but no such waiver by LESSOR
will be construed as a waiver of such rules and regulations in favor of any
other lessee or lessees, nor prevent LESSOR from enforcing any such rules and
regulations against any or all of the lessees of the Building after such waiver.

      24. These rules and regulations are in addition to, and will not be
construed to modify or amend, in whole or in part, the terms, covenants,
agreements, and conditions of the Lease.


                                       25

<PAGE>

                                   Exhibit F

                                    Signage

                                     None.


                                       26

<PAGE>

                                   Exhibit G1

                                First Offer Space

Not to Scale                                                  Capital Properties
                                                                  February, 1998

                               [GRAPHIC OMITTED]

                                                       Fifth Floor Stacking Plan
                                                        The Park Square Building

<PAGE>

                                   Exhibit G2
                                First Offer Space

Not to Scale                                                  Capital Properties
                                                                  February, 1998

                               [GRAPHIC OMITTED]

                                                       Tenth Floor Stacking Plan
                                                        The Park Square Building