1
                                                                   Exhibit 10.12


                                 SIXTH AMENDMENT

THIS SIXTH AMENDMENT (the "Amendment") is made and entered into as of the 30th
day of DECEMBER 1999, by and between EOP-2 OLIVER STREET, L.L.C., A DELAWARE
LIMITED LIABILITY COMPANY ("Landlord"), and AMR RESEARCH, INC., A DELAWARE
CORPORATION ("Tenant").

WITNESSETH

A.   WHEREAS, Landlord (as successor in interest to MLH Income Realty
     Partnership V, a New York limited partnership) and Tenant (as successor in
     interest to Advanced Manufacturing Research, a Massachusetts corporation)
     are parties to that certain lease dated August 13, 1992, as amended by that
     certain First Amendment to Lease Agreement dated December 31, 1994, by that
     certain Second Amendment dated January 23, 1996, by that certain Third
     Amendment dated October 15, 1996, by that certain Fourth Amendment dated
     January 8, 1998 and by that certain Fifth Amendment dated July 27, 1998
     (collectively the Lease") for space currently containing approximately
     35,128 rentable square feet (the "Current Premises") on the 4th, 5th and
     6th floors of the building commonly known as 2 Oliver Street and the
     address of which is 2 Oliver Street, Boston, Massachusetts 02109 (the
     "Building"); and

B.   WHEREAS, Tenant has requested that additional space containing
     approximately 12,973 rentable square feet on the 6th floor of the Building,
     shown on EXHIBIT A hereto (the "Sixth Amendment Expansion Space") be added
     to the Current Premises and that the Lease be appropriately amended and
     Landlord is willing to do the same on the terms and conditions hereinafter
     set forth,

     NOW, THEREFORE, in consideration of the mutual covenants and agreements
herein, contained and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Landlord and Tenant agree as
follows:

I.   EXPANSION AND EFFECTIVE DATE. Effective as of the earlier of (i) the 45th
     day from and including the date Landlord delivers possession of the Sixth
     Amendment Expansion Space to Tenant free from occupancy by any party and
     (ii) the day Tenant occupies the Sixth Amendment Expansion Space for the
     conduct of its business (the earlier of such dates shall be the "Expansion
     Effective Date"), the Premises, as defined in the Lease, is increased from
     35,128 rentable square feet on the 4th, 5th and 6th floors to 48,101
     rentable square feet on the 4th , 5th and 6th floors by the addition of the
     Sixth Amendment Expansion Space, and from and after the Expansion Effective
     Date, the Current Premises and the Sixth Amendment Expansion Space,
     collectively, shall be deemed the Premises, as defined in the Lease. The
     Term of the Lease for the Sixth Amendment Expansion Space shall commence on
     the Expansion Effective Date and end on the termination date. The Sixth
     Amendment Expansion Space is subject to all the terms and conditions of the
     Lease, except as expressly modified herein and except that Tenant shall not
     be entitled to receive any allowances, abatements or other financial
     concessions granted with respect to the Current Premises unless such
     concessions are expressly provided for herein with respect, to the Sixth
     Amendment Expansion Space.

II.  ANNUAL RENT.

     In addition to Tenant's obligation to pay annual rent for the Current
     Premises, Tenant shall pay Landlord the sum of $2,176,220.75 as total
     annual rent for the Sixth Amendment Expansion Space in 61 equal
     installments of $35,675.75 each payable on or before the first day of each
     month during the period beginning May 1, 2000 and ending May 31, 2005.

     All such annual rent shall be payable by Tenant in accordance with the
     terms of Article 4 of the Lease.

     Landlord and Tenant acknowledge that the foregoing schedule is based on the
     assumption that the Expansion Effective Date is May 1, 2000. If the
     Expansion Effective Date is other than the May 1, 2000, the schedule set
     forth above with respect to the payment of




   2

     any installment(s) of annual rent for the Sixth Amendment Expansion Space
     shall be appropriately adjusted on a per diem basis to reflect the actual
     Expansion Effective Date and the actual Expansion Effective Date shall be
     set forth in a confirmation letter to be prepared by Landlord. However, the
     effective date of any increases or decreases in the annual rent rate shall
     not be postponed as a result of an adjustment of the Expansion Effective
     Date as provided above.

III. ADDITIONAL SECURITY DEPOSIT. Upon Tenant's execution hereof, Tenant shall
     pay Landlord the sum of $210,069.71 which is added to and becomes part of
     the Security Deposit held by Landlord as provided under the Lease as
     security for payment of Rent and the performance of the other terms and
     conditions of the Lease by Tenant. Accordingly, simultaneous with the
     execution hereof, the Security Deposit is increased from,$89,930.29 to
     $300,000.00. All of the Security Deposit may be in the form of an
     irrevocable letter of credit (the "Letter of Credit"), which Letter of
     Credit shall: (a) be in the amount of $300,000.00; (b) be issued on the
     form attached hereto as Exhibit B; (c) name Landlord as its beneficiary;
     (d) be drawn on an FDIC insured financial institution satisfactory to the
     Landlord, and (e) expire no earlier than 60 days after the Termination Date
     of this Lease.

IV.  TENANT'S PERCENTAGE. For the period commencing with the Expansion Effective
     Date and ending on the termination date, Tenant's percentage for the Sixth
     Amendment Expansion Space is 6.1107%.

V.   OPERATING COSTS. For the period commencing with the Expansion Effective
     Date and ending on the termination date, Tenant shall pay for its
     percentage of Operating Costs applicable to the Sixth Amendment Expansion
     Space in accordance with the terms of the Lease, provided, however, during
     such period, the Tax Cost Base for the computation of Tenant's percentage
     of Operating Costs applicable to the Sixth Amendment Expansion Space is the
     actual taxes for fiscal year 2000 (i.e., July 1, 1999: to June 30, 2000)
     and the Base for all other Occupancy Costs for the computation of Tenant's
     percentage of Operating Costs applicable to the Sixth Amendment Expansion
     Space is the actual amount of Operating Costs for calendar year 2000.

VI.  IMPROVEMENTS TO SIXTH AMENDMENT EXPANSION SPACE

     A.   CONDITION OF SIXTH AMENDMENT EXPANSION SPACE. Tenant has inspected the
          Sixth Amendment Expansion Space and agrees to accept the same "as is"
          without any agreements, representations, understandings or obligations
          on the part of Landlord to perform any alterations, repairs or
          improvements, except as may be expressly provided otherwise in this
          Amend rent, or as Landlord may be otherwise required to perform
          pursuant to the Lease.

          Landlord and Tenant hereby acknowledge and agree that as of the date
          hereof, the HVAC system serving the Sixth Amendment Expansion Space
          provides adequate heating, ventilation and air conditioning to the
          Premises. In the event Tenant' requires additional heating,
          ventilation and/or air conditioning in the Sixth Amendment Expansion
          Space, such additional service(s) shall be subject to the terms of the
          Lease and at Tenant's sole cost and expense (subject to the
          Improvement Allowance).

     B.   COST OF IMPROVEMENTS TO SIXTH AMENDMENT EXPANSION SPACE. Tenant shall
          be entitled to receive an improvement allowance (the "Improvement
          Allowance") in an amount not to exceed $330,811.50 (i.e., $25.50 per
          rentable square foot of the Sixth Amendment Expansion Space) to be
          applied toward the cost of performing, initial construction,
          alteration or improvement of the Sixth Amendment Expansion Space,
          including but not limited to the cost of space planning, design and
          related, architectural and engineering services (the "Improvement
          Work"). The Improvement Allowance shall be paid to Tenant or, at
          Landlord's option, to the order of the general contractor that
          performed the Improvement Work, within 30 days following receipt by
          Landlord of (1) receipted bills covering all labor and materials
          expended and used in the Improvement Work; (2) a sworn contractor's
          affidavit from the general contractor and a request to disburse from
          Tenant



                                       2

   3

          containing an approval by Tenant of the work done; (3) full and final
          waivers of lien; (4) as-built plans of the Improvement Work; and (5)
          the certification of Tenant and its architect that the Improvement
          Work has been installed in a good and workmanlike manner in accordance
          with the approved plans, and in accordance with applicable laws, codes
          and ordinances. The Improvement Allowance shall be disbursed in the
          amount reflected on the receipted bills meeting the requirements
          above. Notwithstanding anything herein to the contrary, Landlord shall
          not be obligated to disburse any portion of the improvement Allowance
          during the continuance of an uncured default under the Lease, and
          Landlord's obligation to disburse shall only resume when and if such
          default is cured. In the event the total cost of the Improvement Work
          exceeds the Improvement Allowance, Tenant shall pay such excess
          directly to the contractors performing the Improvement Work. In the
          event Tenant does not properly submit a request for payment of the
          entire Improvement Allowance to Landlord in accordance with the
          provisions of the subsection B on or before August 31, 2000, any
          unused amount of the Improvement Allowance shall accrue to the sole
          benefit of Landlord, it being understood that Tenant shall not be
          entitled to any credit, abatement or other concession in connection
          therewith.

     C.   RESPONSIBILITY FOR IMPROVEMENTS TO SIXTH AMENDMENT EXPANSION SPACE.

          (i)  Any construction, alterations or improvements made to the Sixth
               Amendment Expansion Space shall be performed by Tenant using
               contractors selected by Tenant and approved by Landlord, shall be
               made at Tenant's sole cost and expense, subject to the
               Improvement Allowance and shall be governed in all respects by
               the provisions of Article 7 of the Lease. Landlord's approval of
               the contractors to perform the Improvement Work shall not be
               unreasonably withheld. The parties agree that Landlord's approval
               of the general contractor to perform the Improvement Work shall
               not be considered to be unreasonably withheld if any such general
               contractor (a) does hot have trade references reasonably
               acceptable to Landlord, (b) does not maintain insurance as
               required pursuant to the terms of the Lease, (c) does not have
               the ability to be bonded for the work, (d) does not provide
               current financial statements reasonably acceptable to Landlord,
               or (e) is not licensed as a contractor in the state/municipality
               in which the Sixth Amendment Expansion Space is located. Tenant
               acknowledges the foregoing is not intended to be an exclusive
               list of the reasons why Landlord may reasonably withhold its
               consent to a general contractor.

          (ii) Space planning, architectural and engineering (mechanical,
               electrical and plumbing) drawings for the Improvement Work shall
               be prepared by Tenant's architect at Tenant's sole cost and
               expense, subject to the Improvement Allowance. The space
               planning, architectural and mechanical drawings are collectively
               referred to herein as the "Plans".

          (iii) Tenant shall submit the Plans to Landlord for review and
               approval. Landlord agrees to review the Plans and notify Tenant
               of the matters, if any, in which said Plans fail to conform to
               Landlord's construction requirements or otherwise fail to meet
               with Landlord's approval. Tenant shall cause said Plans to be
               revised in such manner as to comply with Landlord's requirements
               and resubmit the same to Landlord.

VII. EARLY ACCESS TO SIXTH AMENDMENT EXPANSION SPACE. During any period that
     Tenant shall be permitted to enter the Sixth Amendment Expansion Space
     prior to the Expansion, Effective Date (e.g.. to perform alterations or
     improvements, if any), Tenant shall comply with all terms and provisions of
     the Lease, except those provisions requiring payment of, annual rent or
     additional rent as to the Sixth Amendment Expansion Space. If Tenant takes
     possession of the Sixth Amendment Expansion Space prior to the Expansion
     Effective Date for any reason whatsoever (other than the performance of
     work in the Sixth Amendment Expansion Space with Landlord's prior
     approval), such possession shall be subject to all the terms and conditions
     of the Lease and this Amendment, and



                                       3

   4

          Tenant shall pay annual rent and additional rent as applicable to the
          Sixth Amendment Expansion Space to Landlord on a per diem basis for
          each day of occupancy prior to the Expansion Effective Date.

VIII. CONTINGENCIES.

     A.   Landlord and Tenant hereby acknowledge that a portion of the Sixth
          Amendment Expansion Space consisting of approximately 1.750 rentable
          square feet (the "R&S Space") is currently leased to Russo & Scolnick
          ("R&S") pursuant to a lease that is currently scheduled to expire
          January 31, 2002. Landlord is currently engaged in good faith
          discussions with R&S with respect to an agreement (The "R&S
          Agreement") under which R&S would relocate from the R&S Space to new
          space in the Building (the "R&S Relocation Space"). This Amendment is
          contingent upon the execution of the R&S Agreement by Landlord and R&S
          on or before April 1, 2000. In the event that Landlord and R&S fail to
          enter into the R&S Agreement on or before April 1, 2000, Landlord
          shall have the right to terminate this Amendment by the delivery of
          written notice to Tenant on or before the date on which the R&S
          Agreement is entered into by Landlord and R&S.

     B.   In addition, Landlord and Tenant hereby acknowledge that a portion of
          the Sixth Amendment Expansion Space consisting of' approximately 1,187
          rentable square, feet (the "R&S Space") is currently leased to Peter
          L. Samek ("Samek") pursuant to a lease that is currently scheduled to
          expire June 30, 2002. Landlord is currently engaged in good faith
          discussions with Samek with respect to an agreement (the "Samek
          Agreement") under which Samek would relocate from the Samek Space to
          new space in the Building (the "Samek Relocation Space"). This
          Amendment is contingent upon the execution of the Samek Agreement by
          Landlord and Samek on or before April 1, 2000. In the event that
          Landlord and Samek fail to enter into the Samek Agreement on or before
          April 1, 2000, Landlord shall have the right to terminate this
          Amendment by the delivery of written notice to Tenant on or before the
          date on which the Samek Agreement is entered into by Landlord and
          Samek. In any case, this agreement will terminate April 1, 2000, if
          Landlord has not entered into an agreement with R&S and Samek
          Associates.

IX.  RELOCATION REIMBURSEMENT. Landlord and Tenant hereby acknowledge that all
     costs of and related to the relocation of R&S to the R&S Relocation Space
     and Samek to the Samek Relocation Space shall be at Tenant's sole cost and
     expense (the "Relocation Costs"). Such costs shall include, without
     limitation, (a) alterations, construction and improvements to the R&S
     Relocation Space and the Samek Relocation Space, (b) space planning, design
     and related architectural and engineering services, (c) relocation of
     telecommunications equipment and cabling, (d) additional lighting and (e)
     reasonable out-of-pocket costs incurred by R&S and Samek (i.e., reprinting
     stationary and business cards and similar items). Tenant hereby
     acknowledges and agrees that Landlord shall be entitled to deduct the
     Relocation Costs from the Improvement Allowance prior to the distributing
     any of the Improvement Allowance to Tenant or the general contractor. In
     addition, Landlord shall be entitled to deduct from the Improvement
     Allowance a management fee for Landlord's review of plans related to the
     relocation of R&S and Samek, coordination of Building services and
     oversight of the work required to the R&S Relocation Space and the Samek
     Relocation Space in an amount equal to 5% of the total Relocation Costs.

X.   MISCELLANEOUS.

     A.   This Amendment sets forth the entire agreement between the parties
          with respect to the matters set forth herein. There have been no
          additional oral or written representations or agreements. Under no
          circumstances shall Tenant be entitled to any rent abatement,
          improvement allowance, leasehold improvements, or other work to the
          Premises, or any similar economic incentives that may have been
          provided Tenant in connection with entering into the Lease, unless
          specifically set forth in this Amendment.


                                       4

   5

     B.   Except as herein modified or amended, the provisions, conditions and
          terms of the Lease shall remain unchanged and in full force and
          effect.

     C.   In the case of any inconsistency between the provisions of the Lease
          and this Amendment, the provisions of this Amendment shall govern and
          control.

     D.   Submission of this Amendment by Landlord is not an offer to enter into
          this Amendment but rather is a solicitation for such an offer by
          Tenant. Landlord shall not be bound by this Amendment until Landlord
          has executed and delivered the same to Tenant.

     E.   The capitalized terms used in this Amendment shall have the same
          definitions as set forth in the Lease to the extent that such
          capitalized terms are defined therein and not redefined in this
          Amendment.

     F.   Tenant hereby represents to Landlord that Tenant has dealt with no
          broker in connection with this Amendment. Tenant agrees to indemnify
          and hold Landlord, its members, principals, beneficiaries, partners,
          officers, directors, employees, mortgagee(s) and agents, and the
          respective principals, and members of any such agents (collectively,
          the "Landlord Related Parties") harmless from all claims of any
          brokers claiming to have represented Tenant in connection with this
          Amendment. Landlord hereby represents to Tenant that Landlord has
          dealt with no broker in connection with this Amendment. Landlord
          agrees to indemnify and hold Tenant, its members, principals,
          beneficiaries, partners, officers, directors, employees, and agents,
          and the respective principals and members of any such agents
          (collectively, the "Tenant Related Parties") harmless from all claims
          of any brokers claiming to have represented Landlord in connection
          with this Amendment.


     G.   This Amendment shall be of no force and effect unless and until
          accepted by any guarantors of the Lease, who by signing below shall
          agree that their guarantee shall apply to the Lease as amended herein,
          unless such requirement is waived by Landlord in writing.

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

WITNESS/ATTEST:                       LANDLORD:

                                      EOP-2 OLIVER STREET, L.L.C., A DELAWARE
                                      LIMITED LIABILITY COMPANY

                                      By:  EOP Operating Limited Partnership, a
                                           Delaware limited partnership, its
                                           sole member

                                           By: Equity Office Properties Trust,
                                               a Maryland real estate investment
                                               trust, its managing general
                                               partner

/s/ Sarah L. Wills                             By: /s/ Thomas Q. Bakke
- ---------------------------------                 -----------------------------

Name (print):                                  Name: /s/ Thomas Q. Bakke
                                                    ---------------------------

/s/ Sarah L. Wills                             Title: Vice President
- ---------------------------------                    --------------------------

Name (print):



                                       5
   6



WITNESS/ATTEST:                        TENANT

                                       AMR RESEARCH, INC., A DELAWARE
                                       CORPORATION

                                       By: /s/ Anthony J. Friscia
                                          ------------------------------------

/s/ Karen M. Sullivan                  Name: /s/ Anthony J. Friscia
- -----------------------------------         ----------------------------------

Name (print): /s/ Karen M. Sullivan    Title: PRESIDENT
             ----------------------          ---------------------------------

/s/ Lisa O'Soro
- -----------------------------------

Name (print): /s/ Lisa O'Soro
             ----------------------








                                       6
   7


                           EXHIBIT A, SIXTH AMENDMENT
                             DATE: DECEMBER 28, 1999

       [FLOOR PLAN - SIXTH AMENDMENT EXPANSION SPACE OF TWO OLIVER STREET]









                                       7

   8

                                    EXHIBIT B

                             SAMPLE LETTER OF CREDIT

                         [Name of Financial Institution]


                                                      Irrevocable Standby
                                                      Letter of Credit
                                                      No. __________________
                                                      Issuance Date:________
                                                      Expiration Date: _____
                                                      Applicant: ___________

BENEFICIARY

[Insert Name of Owner]
- ------------------------------

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

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

Ladies/Gentlemen:

     We hereby establish our Irrevocable Standby Letter of Credit in your favor
for the account of the above referenced Applicant in the amount of U. S. Dollars
($________________) available for payment at sight by your draft drawn on us
when accompanied by the following documents:

1.   An original copy of this Irrevocable Standby Letter of Credit.

2.   Beneficiary's dated statement purportedly signed by one of its officers
     reading: "This draw in the amount of U.S. Dollars ($____________) under
     your Irrevocable Standby Letter of Credit No. ___________ represents funds
     due and owing to us as a result of the Applicant's failure to comply with
     one or more of the terms of that certain lease by and between
     ______________, as landlord, and ____________, as tenant."

     It is a condition of this Irrevocable Standby Letter of Credit that it will
be considered automatically renewed for a one year period upon the expiration
date set forth above and upon each anniversary of such date, unless at least
sixty (60) days prior to such expiration date or applicable anniversary thereof,
we notify you in writing by certified mail, return receipt requested, that we
elect not to so renew this Irrevocable Standby Letter of Credit. A copy of any
such notice shall also be sent to: Equity Office Properties Trust, 2 North
Riverside Plaza, Suite 2200, Chicago, IL 60606, Attention: Vice President
Corporate Operations. In addition to the foregoing, we understand and agree that
you shall be entitled to draw upon this Irrevocable Standby Letter of Credit in
accordance with 1 and 2 above in the event that we, elect not to renew this'
Irrevocable Standby Letter of Credit and, in addition, you provide us with a
dated statement purportedly signed by one of Beneficiary's officers stating that
the Applicant has failed to provide, you with an acceptable substitute
irrevocable standby letter of credit in accordance with the, terms of the above
referenced lease. We further acknowledge and agree that: (a) upon receipt of the
documentation required herein, we will honor your draws against this Irrevocable
Standby Letter of Credit without inquiry into the accuracy of Beneficiary's
signed statement and regardless of whether Applicant disputes the content of
such statement; (b) this Irrevocable Standby Letter of Credit shall permit
partial draws and, in the event you elect to draw upon less than the full stated
amount hereof, the stated amount of this Irrevocable Standby Letter of Credit
shall be automatically reduced by the amount of such partial draw; and (c) you
shall be entitled to assign your interest in this irrevocable Standby Letter of
Credit from time to time without our approval and without charge. In the event
of an assignment, we reserve the right to require reasonable evidence of such
assignment as a condition to any draw hereunder.

     This Irrevocable Standby Letter of Credit is subject to the Uniform Customs
and Practice for Documentary Credits (1993 revision) ICC Publication No. 500.


                                       8

   9


     We hereby engage with you to honor drafts and documents drawn under and in
compliance with the terms of this Irrevocable Standby Letter of Credit.

     All communications to us with respect to this Irrevocable Standby Letter of
Credit must be addressed to our office located at ____________________________
to the attention of __________________________________________________.

                                               Very truly yours,

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

                                                        [NAME]
                                               -------------------------

                                                        [TITLE]
                                               -------------------------




                                        9