Document:

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                                                                  Exhibit 10.6

                           TAX ALLOCATION AGREEMENT
                           ------------------------

     This Tax Allocation Agreement (this "Agreement") is entered into as of
August 25, 2000 by and between Arthur D. Little, Inc., a Massachusetts
corporation, and c-quential, Inc., a Delaware corporation.

     WHEREAS, the execution and delivery of this Agreement is a condition to the
transactions contemplated by the Reorganization Agreement dated as of August 25,
2000 by and among Arthur D. Little, Inc., c-quential, Inc. and other parties
thereto (the "Reorganization Agreement");

     NOW, THEREFORE, in consideration of the mutual promises and agreements set
forth herein, and other valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the parties hereto agree as follows:

SECTION 1.  DEFINITIONS.
            -----------

     Section 1.1  Defined Terms.  For purposes of this Agreement, the following
                  -------------
terms shall have the following meanings.

     "Affiliated Group" means an affiliated group within the meaning of Section
1504(a) of the Code.

     "Ancillary Agreement" shall have the meaning given to such term in the
Reorganization Agreement, excluding this Agreement.

     "ADL Affiliated Group" means Parent and all other corporations that may now
or from time to time hereafter constitute an Affiliated Group with Parent as the
Common Parent.

     "Code" means the Internal Revenue Code of 1986, as amended.

     "Combined Return" means any Return (other than a Consolidated Return) that
is filed on a consolidated, combined or unitary basis (including any state,
local, or foreign Return filed on such basis) that includes at least one Parent
Subsidiary and one Sub Subsidiary.

     "Combined Tax" means any Tax reported on a Combined Return.

     "Combined Utilized Tax Benefit" means, for any period reported on a
Combined Return, the reduction (if any) in Combined Taxes resulting from the use
by the group of entities included in such Combined Return of any credits,
deductions, losses or other items attributable to the Sub Subsidiaries that
could not be used to reduce the Hypothetical Combined Tax or increase the
Hypothetical Combined Refund for such period or any prior period reported on a
Combined Return.

     "Common Parent" means the common parent, within the meaning of Section
1504(a) of the Code, of an Affiliated Group.
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     "Consolidated Return" means the Federal Income Tax Return of the ADL
Affiliated Group for any Consolidated Return Year.

     "Consolidated Return Year" means any taxable year (i) during any part of
which Sub is a member of the ADL Affiliated Group, and (ii) with respect to
which the ADL Affiliated Group files a consolidated Federal Income Tax Return
under Section 1501 of the Code.

     "Consolidated Tax" means any Tax reported on a Consolidated Return.

     "Effective Date" shall have the meaning given to such term in the
Reorganization Agreement.

     "Estimated Payment Date" means any date in a Consolidated Return Year upon
which the ADL Affiliated Group is required to make a payment of estimated
Federal Income Tax.

     "Federal Income Tax" means any Tax imposed by Subtitle A of the Code.

     "Federal Income Tax Return" means a Return filed with respect to Federal
Income Taxes.

     "Federal Utilized Tax Benefit" means, for any Consolidated Return Year, the
reduction (if any) in Consolidated Taxes resulting from the use by the ADL
Affiliated Group of any credits, deductions, losses or other items attributable
to the Sub Group that could not be used to reduce the Hypothetical Federal Tax
or increase the Hypothetical Federal Refund for such Consolidated Return Year or
any prior Consolidated Return Year.

     "Hypothetical Combined Tax" and "Hypothetical Combined Refund" are defined
in Section 5.

     "Hypothetical Federal Tax" and "Hypothetical Federal Refund" are defined in
Section 4.

     "Independent Director" with respect to Sub, shall mean a member of the Sub
Board of Directors who is not an employee or officer of Sub or an officer,
employee or director of Parent or a member of the Parent Group, and with respect
to Parent, shall mean a member of the Parent Board of Directors who is not an
employee or officer of Parent or a member of the Parent Group.

     "Parent" means Arthur D. Little, Inc., a Massachusetts corporation, or any
successor thereto.

     "Parent Group" means the ADL Affiliated Group excluding the Sub Group.

     "Parent Subsidiary" means Parent or any entity in which Parent holds a
direct or indirect interest, excluding all Sub Subsidiaries.

     "Reorganization Agreement" is defined in the recitals to this Agreement.

     "Reorganization Tax" means any Tax imposed upon any Parent Subsidiary or
Sub Subsidiary with respect to the Reorganization Transaction, including but not
limited to any transfer Tax and any Tax imposed on realized gain.

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     "Reorganization Tax Benefit" means the excess of (i) the Total Sub Taxes
that would be incurred if the Reorganization Transaction were treated as giving
rise to no Reorganization Tax over (ii) the Total Sub Taxes actually incurred.
Whenever the Reorganization Tax Benefit is calculated, each of the amounts
referred to in clauses (i) and (ii) of the preceding sentence shall be such
amounts as of the date of the calculation.

     "Reorganization Transaction" means all of the transactions contemplated in
the Reorganization Agreement and Ancillary Agreements considered collectively,
excluding transactions contemplated in the Corporate Services Agreement, the
Registration Rights Agreement or the Use and Occupancy Agreement.

     "Return" means any Tax return, statement, report, form or election
(including, without limitation, estimated Tax returns and reports, extension
requests and forms, and information returns and reports) required to be filed
with any Taxing Authority, in each case as amended.

     "Return Due Date" means, with respect to any Return, the earlier of (i) the
due date (including extensions) of such Return, or (ii) the date such Return is
filed.

     "Spin-Off" means a distribution of stock of Sub that is intended to qualify
as a transaction described in Section 355 of the Code.

     "Spin-Off Tax" means any Tax incurred by the Parent Group or the Sub Group
(i) as a result of a Spin-Off failing to qualify as a transaction described in
Section 355 of the Code, or (ii) through the application of Section 355(d) or
(e) of the Code to a Spin-Off.

     "Sub" means c-quential, Inc., a Delaware corporation, or any successor
thereto.

     "Sub Group" means the group of corporations that would constitute a
separate Affiliated Group with Sub as the Common Parent if Sub were not a member
of the ADL Affiliated Group.

     "Sub Subsidiary" means Sub or any entity in which Sub holds a direct or
indirect interest.

     "Tax" means any tax imposed by the Code, and any net income, capital gains,
alternative or add-on minimum, gross income, gross receipts, sales, use, ad
valorem, value added, transfer, franchise, profits, license, withholding (as
payor or recipient), payroll, employment, excise, severance, stamp, capital
stock, occupation, property, real property gains, environmental, windfall,
premium, custom, duty or other tax, recording fee, governmental fee or other
like assessment or charge of any kind whatsoever imposed by any domestic or
foreign jurisdiction, together with any related interest, penalties, additions
to tax and related costs and expenses (including but not limited to legal and
accounting fees).

     "Tax Adjustment" means any adjustment (whether positive or negative)
required by a Taxing Authority, or appearing in an amended Return, to any Tax
liability or item reflected (or which should have been reflected) in any Return.

     "Tax Advisor" means an attorney, law firm, accountant, accounting firm or
other person designated by a party as its tax advisor.

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     "Tax Dispute" means any dispute, controversy or claim between any Parent
Subsidiary and any Sub Subsidiary arising out of or relating to this Agreement,
including without limitation the breach, interpretation or validity of any term
or condition hereof, or the withholding by Sub or Parent (whether reasonably or
unreasonably) of any approval required hereunder other than a consent described
in Section 6.1.

     "Taxing Authority" means any governmental authority or any subdivision,
agency, commission or authority thereof, or any quasi-governmental or private
body having jurisdiction over the assessment, determination, or imposition of
any Tax.

     "Tax Proceeding" means any Tax audit, dispute or proceeding (whether
administrative or judicial).

     "Total Sub Taxes" means the sum of (i) Taxes paid by Sub Subsidiaries, (ii)
Hypothetical Federal Taxes and (iii) Hypothetical Combined Taxes, less the sum
of (x) Tax refunds received by Sub Subsidiaries, (y) Hypothetical Federal
Refunds and (z) Hypothetical Combined Refunds.  Whenever Total Sub Taxes are
calculated, each of the amounts referred to in clauses (i), (ii), (iii), (x),
(y) and (z) of the preceding sentence shall be the total of all such amounts
(with Tax Adjustments taken into account) for all periods beginning on or after
the Effective Date (or, with respect to any period beginning before and ending
after the Effective Date, the portion of such period beginning on the day after
the Effective Date) and ending on or before the date of the calculation.  Total
Sub Taxes may be either positive or negative.

SECTION 2.  TAX RETURNS, PAYMENTS AND PROCEEDINGS.
            -------------------------------------

     Section 2.1  Consolidated Returns.
                  --------------------

          (a) Parent shall be responsible for the preparation and filing of all
Consolidated Returns; provided, however, that Sub shall have the right to
review, at least 10 days prior to the Return Due Date of any Consolidated
Return, a draft of the portion of such Return that reflects the operations and
tax items of the Sub Group.

          (b) Parent shall be responsible for the payment of all Federal Income
Taxes attributable to Consolidated Return Years, and shall be entitled to all
Federal Income Tax refunds attributable to Consolidated Return Years.

     Section 2.2  Combined Returns.
                  ----------------

          (a) Parent shall be responsible for the preparation and filing of all
Combined Returns; provided, however, that Sub shall have the right to review, at
least 10 days prior to the Return Due Date of any Combined Return, a draft of
the portion of such Return that reflects the operations and tax items of the Sub
Subsidiaries included in such Return.

          (b) Parent shall be responsible for the payment of all Taxes
attributable to periods and items reflected (or which should have been
reflected) in any Combined Return, and shall be entitled to all Tax refunds
attributable to periods and items reflected (or which should have been
reflected) in any Combined Return.

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     Section 2.3  Tax Proceedings Respecting Consolidated and Combined Returns.
                  ------------------------------------------------------------
Tax Proceedings respecting any Consolidated Return or Combined Return shall be
controlled by Parent.

     Section 2.4  Other Party's Tax Objectives Taken Into Account.  In the
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preparation of all Returns and in the conduct of all Tax ProceedingsX

          (a) the Parent Subsidiaries shall take into account and promote the
Tax objectives of the Sub Subsidiaries, provided that, in so doing, the Parent
Subsidiaries are not adversely affected; and

          (b) the Sub Subsidiaries shall take into account and promote the Tax
objectives of the Parent Subsidiaries, provided that, in so doing, the Sub
Subsidiaries are not adversely affected.

SECTION 3.  REORGANIZATION TAXES; TAX BENEFITS
            ----------------------------------

     Section 3.1  Parent Responsible for Pre-Effective Date Taxes.
                  -----------------------------------------------

          (a) Parent shall be responsible for the payment of all Taxes of all
Sub Subsidiaries incurred with respect to periods ending on or before the
Effective Date.

          (b) With respect to any period that begins before and ends after the
Effective Date, Parent shall be responsible for the payment of all Taxes of all
Sub Subsidiaries incurred with respect to the portion of such period ending on
the Effective Date.

     Section 3.2  Parent Responsible for Reorganization Taxes.  Parent shall be
responsible for the payment of all Reorganization Taxes (including
Reorganization Taxes reported on Returns filed by Sub Subsidiaries).

     Section 3.3  Reimbursement for Reorganization Tax Benefits.
                  ---------------------------------------------

          (a) The amount of the Reorganization Tax Benefit shall be calculated
at such times as Parent may reasonably request, provided, however, that it be
calculated annually.

          (b) Promptly upon the approval by Sub and Parent of the calculation
referred to in Section 3.3(a) (which approval shall not be unreasonably
withheld)X

               (I) Sub shall pay to Parent the excess (if any) of the
Reorganization Tax Benefit over the total of all payments previously made by Sub
under this Section 3.3 (net of the total of all payments previously made by
Parent under this Section 3.3), and

               (II) Parent shall pay to Sub the excess (if any) of the total of
all payments previously made by Sub under this Section 3.3 (net of the total of
all payments previously made by Parent under this Section 3.3) over the
Reorganization Tax Benefit.

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          (c) Notwithstanding any other provision of this Section 3.3, the total
of all payments made by Sub under this Section 3.3 (net of the total of all
payments made by Parent under this Section 3.3) shall not exceed the total of
all Reorganization Taxes.

     Section 3.4  Reimbursement for Federal Utilized Tax Benefits.
                  -----------------------------------------------

          (a) The amount of the Federal Utilized Tax Benefit for any
Consolidated Return Year shall be calculated at such time as Sub may reasonably
request, provided, however, that it be calculated annually.

          (b) Promptly upon the approval by Sub and Parent of the calculation
referred to in Section 3.4(a) (which approval shall not be unreasonably
withheld), Parent shall pay to Sub the amount (if any) of the Federal Utilized
Tax Benefit.

          (c) When any Tax Adjustment becomes final, the Federal Utilized Tax
Benefit for each affected Consolidated Return Year shall be recalculated taking
such Tax Adjustment into account.  After approval by Parent and Sub of such a
recalculation for any affected Consolidated Return Year (which approval shall
not be unreasonably withheld), Sub shall pay to Parent or Parent shall pay to
Sub (as appropriate) an amount equal to the difference between the recalculated
Federal Utilized Tax Benefit for such affected Consolidated Return Year and any
amounts previously paid with respect to such Consolidated Return Year under this
Section 3.4, together with interest thereon at the rate interest would be paid
on a Federal Income Tax overpayment (in the case of a payment by Parent to Sub)
or on a Federal Income Tax underpayment (in the case of a payment by Sub to
Parent) paid at the time of such payment.

     Section 3.5  Reimbursement for Combined Utilized Tax Benefits.  Payments
                  ------------------------------------------------
shall be made with respect to all Combined Utilized Tax Benefits, and the
calculation and recalculation of the amounts of such payments, and the approval
and timing of such payments, shall be similar to and consistent with the
procedures set out in Section 3.4.

     Section 3.6  Partial Years.  If Sub is a member of the ADL Affiliated Group
                  -------------
for less than an entire Consolidated Return Year, or if all of the Sub
Subsidiaries that are included in a Combined Return for any period are
includible for less than the entire period, the calculation of the
Reorganization Tax Benefit, Federal Utilized Tax Benefit and/or Combined
Utilized Tax Benefit (as appropriate) shall be similar to and consistent with
the procedures set out in Section 4.2.

SECTION 4.  INTERCOMPANY PAYMENTS RESPECTING FEDERAL INCOME TAXES.
            -----------------------------------------------------

     Section 4.1  Hypothetical Federal Taxes and Refunds.  For each Consolidated
                  --------------------------------------
Return YearX

          (a) Sub shall pay to Parent an amount equal to the amount of any
Federal Income Tax for which Sub would have been liable (including interest for
which Sub would have been liable, but excluding Tax penalties for which Sub
would have been liable) had Sub filed consolidated Federal Income Tax Returns
for the Sub Group, separate and apart from the Parent Group, for all periods
beginning on or after Effective Date (the "Hypothetical Federal Tax");

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          (b) Parent shall pay to Sub an amount equal to the amount of any
refund of Federal Income Tax that Sub would have received (including interest
that Sub would have received) had Sub filed consolidated Federal Income Tax
Returns for the Sub Group, separate and apart from the Parent Group, for all
periods beginning on or after the Effective Date (the "Hypothetical Federal
Refund");

          (c) the calculation of the Hypothetical Federal Tax or Hypothetical
Federal Refund shall be made by assuming that Sub made such Tax elections and
choices of methods as would most benefit the Sub Group;

          (d) the calculation of the Hypothetical Federal Tax or Hypothetical
Federal Refund shall be made by Parent and submitted to Sub for review and
approval at least 10 days prior to the Return Due Date of the Consolidated
Return for the Consolidated Return Year, and Sub's approval of such calculation
shall not be unreasonably withheld;

          (e) except as provided in Section 4.3, all payments required by this
Section 4.1 shall be paid promptly upon the approval referred to in Section
4.1(d); provided, however, that (except as provided in Section 4.3) no such
payment shall be due prior to 3 days before the Return Due Date of the
Consolidated Return for the Consolidated Return Year; and

          (f) notwithstanding any other provision of this Section 4.1, when
calculating the Hypothetical Federal Tax or Hypothetical Federal Refund for any
Consolidated Return Year, any item which gave rise to a Federal Utilized Tax
Benefit in a prior Consolidated Return Year shall not be taken into account.

     Section 4.2  Sub Not a Member for Entire Consolidated Return Year.  If Sub
                  ----------------------------------------------------
is a member of the ADL Affiliated Group for less than the entire Consolidated
Return Year, the Hypothetical Federal Tax or Hypothetical Federal Refund shall
be calculated by hypothetically closing the books of the Sub Group as of the day
before the first day and as of the last day that Sub is a member of the ADL
Affiliated Group and taking into account only those items that accrue in that
portion of the Consolidated Return Year during which Sub is a member of the ADL
Affiliated Group, unless Sub and Parent agree otherwise.

     Section 4.3  Estimated Payments.  For each Estimated Payment Date in any
                  ------------------
Consolidated Return YearX

          (a) Parent shall calculate for the Sub Group an estimated Hypothetical
Federal Tax in a manner that is similar to and consistent with the Hypothetical
Federal Tax calculations set out in Sections 4.1 and 4.2;

          (b) Sub shall assist and cooperate with Parent in good faith and to
the extent necessary for Parent to make the calculation referred to in Section
4.3(a) reasonably accurately;

          (c) the calculation referred to in Section 4.3(a) shall be submitted
to Sub for review and approval at least 10 days prior to the related Estimated
Payment Date, and Sub's approval of such calculation shall not be unreasonably
withheld; and

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          (d) promptly upon the approval referred to in Section 4.3(c), Sub
shall pay to Parent the approved amount; provided, however, that no such payment
shall be due prior to 3 days before the related Estimated Payment Date.

     Section 4.4  Adjustments for Estimated Payments.  Amounts paid under
Section 4.3 shall be taken into account when calculating the payments due under
Sections 4.1 and 4.2.

     Section 4.5  Tax Adjustments.  When any Tax Adjustment made with respect to
                  ---------------
any Consolidated Return becomes finalX

          (a) Parent shall promptly recalculate the Hypothetical Federal Tax or
Hypothetical Federal Refund for all affected Consolidated Return Years taking
such Tax Adjustment into account;

          (b) the recalculation referred to in Section 4.5(a) shall be promptly
submitted to Sub for review and approval, and Sub's approval of such
recalculation shall not be unreasonably withheld; and

          (c) promptly upon the approval referred to in Section 4.5(b), Sub
shall pay to Parent or Parent shall pay to Sub (as appropriate), an amount equal
to the difference between the recalculated Hypothetical Federal Tax or
recalculated Hypothetical Federal Refund and the Hypothetical Federal Tax or
Hypothetical Federal Refund, together with interest thereon at the rate interest
would be paid on a Federal Income Tax overpayment (in the case of a payment by
Parent to Sub) or on a Federal Income Tax underpayment (in the case of a payment
by Sub to Parent) paid at the time of such payment.

     Section 4.6  Estimated Federal Income Tax Underpayment Penalties. No
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intercompany payments shall be made with respect to Consolidated Tax penalties
except for penalties arising from the underpayment of estimated Consolidated
Taxes.  For each Consolidated Return YearX

          (a) Parent shall calculate for the Sub Group the amount (if any) of
the penalty for underpayment of Federal Income Taxes for which Sub would have
been liable had Sub filed consolidated Federal Income Tax Returns for the Sub
Group, separate and apart from the Parent Group, for all periods beginning on or
after the Effective Date.  Such calculation shall be made in a manner that is
consistent with the Hypothetical Federal Tax calculations set out in Sections
4.1 and 4.2;

          (b) the calculation referred to in Section 4.6(a) shall be submitted
to Sub for review and approval, and Sub's approval of such calculation shall not
be unreasonably withheld; and

          (c) promptly upon the approval referred to in Section 4.6(b), Sub
shall pay to Parent the approved amount (if any).

SECTION 5.  INTERCOMPANY PAYMENTS RESPECTING COMBINED TAXES.
            -----------------------------------------------

     Section 5.1  Payments and Calculations.  Payments between Parent and Sub
shall be made with respect to all Combined Taxes, and the calculation and
recalculation of the amounts

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of such payments, and the review, approval and timing of such payments, shall be
similar to and consistent with the procedures set out in Section 4.

     Section 5.2  Estimated Combined Tax Underpayment Penalties.  No
                  ---------------------------------------------
intercompany payments shall be made with respect to Combined Tax penalties
except for penalties arising from the underpayment of estimated Combined Taxes.
The calculation and payment of any hypothetical estimated Combined Tax
underpayment penalty shall be similar to and consistent with the procedures set
out in Section 4.6.

     Section 5.3  Definitions.  For purposes of this Agreement, the term
                  -----------
"Hypothetical Combined Tax" means an amount calculated under this Section 5 that
is payable by Sub, and the term "Hypothetical Combined Refund" means an amount
calculated under this Section 5 that is payable by Parent.

SECTION 6.  MEMBERSHIP IN AFFILIATED GROUP; CONTROL.
            ---------------------------------------

     Section 6.1  Sub Covenants.  Sub hereby covenants and agrees that it shall
not without Parent's consent (which may be withheld for any reason) take any
action that could result in, or fail to take any action where such failure could
result inX

            (a) Sub no longer being a member of the ADL Affiliated Group;

            (b) the Parent Group no longer being in "control" of Sub within the
meaning of Section 368(c) of the Code; or

            (c) the Parent Group including in income any "excess loss account"
in the stock of Sub under Treasury Regulations Section 1.1502-19;

except to the extent that an outcome described in one or more of the immediately
preceding clauses (a), (b) or (c) is the direct or indirect result of the
exercise (or treatment as exercised under Treasury Regulations Section 1.1504-4)
of options issued (prior to a distribution of Sub stock constituting "control"
of Sub within the meaning of Section 368(c) of the Code) under the c-quential,
Inc. 2000 Stock Option and Incentive Plan (as amended from time to time).

     Section 6.2  Sub Indemnification  Sub shall be responsible for, and shall
                  -------------------
indemnify and hold the Parent Group harmless from, any increase in Taxes caused
by any breach of the covenants set out in Section 6.1, including but not limited
to (i) Taxes incurred by reason of including in income any excess loss account
under Treasury Regulations Section 1.1502-19 that would not have been included
in income in the absence of such breach, (ii) Taxes incurred by reason of
including in income any deferred intercompany gain under Treasury Regulations
Section 1.1502-13 that would not have been included in income in the absence of
such breach, and (iii) Taxes incurred upon a distribution of Sub stock that
would not have been incurred in the absence of such breach.

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SECTION 7.  COOPERATION.
            -----------

     Section 7.1  Cooperation Generally.  Parent and Sub agree to cooperate
fully with each other in connection with all matters subject to this Agreement.
Such cooperation includes but is not limited toX

          (a) making personnel and records available within 10 days (or such
other period as may be reasonable under the circumstances) after a request for
such personnel or records is made by the other party;

          (b) retaining all records which may contain information or provide
evidence relevant to any open taxable period;

          (c) executing, acknowledging and delivering any instrument or document
that may be necessary or helpful in connection with (i) any Return that the
other party has the authority to prepare and file, (ii) any Tax Proceeding that
the other party has the authority to control, or (iii) the carrying out of any
obligation of the other party under this Agreement;

          (d) using best efforts to obtain any documentation from any Taxing
Authority, governmental authority or other third party that may be necessary or
helpful in connection with the foregoing; and

          (e) keeping the other party fully informed with respect to any
material developments relating to any matter subject to this Agreement.

     Section 7.2  Indemnities.  Parent agrees to indemnify and hold harmless
                  -----------
each Sub Subsidiary (and their officers and employees), and Sub agrees to
indemnify and hold harmless each Parent Subsidiary (and their officers and
employees) from any Tax attributable to the negligence or misconduct of a Parent
Subsidiary or Sub Subsidiary, as the case may be, in supplying inaccurate or
incomplete information under Section 7.1.

SECTION 8.  SPIN-OFF PROVISIONS.
            -------------------

     Section 8.1  Prior to the Parent Group engaging in a Spin-Off of Sub,
Parent and Sub shall enter into an agreement that shall include customary
provisions, covenants and indemnities, including but not limited toX

          (a) Sub's indemnity of the Parent Group for any Spin-Off Tax
attributable to any act or omission of the Sub Group, except to the extent that
any Spin-Off Tax is the direct or indirect result of the exercise of options
issued prior to the Spin-Off under the c-quential, Inc. 2000 Stock Option and
Incentive Plan (as amended from time to time).

          (b) Parent's indemnity of the Sub Group for any Spin-Off Tax
attributable to any act or omission of the Parent Group;

          (c) Sub's covenant not to participate in any merger, reorganization,
acquisition, equity restructuring or other transaction that results in one or
more persons acquiring in Sub a 50% or greater interest, within the meaning of
Section 355(e) of the Code, within the 4 year period beginning 2 years prior to
the Spin-Off, except for the issuance of options prior to the Spin-Off, or the
exercise of options issued prior to the Spin-Off, under the c-quential, Inc.
2000 Stock Option and Incentive Plan (as amended from time to time);

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          (d) Parent's covenant not to participate in any merger,
reorganization, acquisition, equity restructuring or other transaction that
results in one or more persons acquiring in Parent a 50% or greater interest,
within the meaning of Section 355(e) of the Code, within the 4 year period
beginning 2 years prior to the Spin-Off;

          (e) customary provisions regarding cooperation, exchange of
information, and control of audits and litigation respecting Taxes; and

          (f) customary provisions regarding consistency in tax return
positions.

SECTION 9.  MISCELLANEOUS.
            -------------

     Section 9.1  Survival.  No provision of the Reorganization Agreement shall
                  --------
operate so as to terminate the operation of any provision of this Agreement.
This Agreement shall survive a Spin-Off or other separation transaction except
to the extent amended by an agreement described in Section 8.1 or an amendment
described in Section 9.4.

     Section 9.2  Confidentiality.  The provisions of the Reorganization
                  ---------------
Agreement relating to confidentiality shall apply with respect to any
information obtained or learned by either party from the other party in
connection with the parties' performance of their respective obligations
hereunder.

     Section 9.3  Tax Dispute Resolution.  All Tax Disputes shall be resolved by
                  ----------------------
mutual agreement of the Tax Advisors of the disputing parties, but if with
respect to any Tax Dispute the Tax Advisors of the disputing parties cannot
reach an agreement, then the disputing parties shall appoint a mutually
agreeable Tax Advisor to resolve the Tax Dispute, and if the disputing parties
cannot agree on a Tax Advisor to so appoint, then the Tax Dispute shall be
resolved in accordance with the provisions of Section 11.3 of the Reorganization
Agreement relating to dispute resolution.

     Section 9.4  Amendment and Waiver.  The provisions of this Agreement,
                  --------------------
including, without limitation, this Section, may not be waived and this
Agreement shall not be amended or modified except in accordance with this
Section.  The provisions of this Agreement may be waived only by the written
consent of a majority of the Independent Directors of the party which is the
beneficiary of the particular provision being waived.  No failure or delay by
any party in exercising any right or remedy hereunder shall operate as a waiver
thereof, and a waiver of a particular right or remedy on one occasion shall not
be deemed a waiver of any other right or remedy or a waiver on any subsequent
occasion.  The provisions of this Agreement may be amended, modified or
supplemented only by the written consent of a majority of the Independent
Directors of each of the parties.

     Section 9.5  Notices.  Any notice to any party hereto given pursuant to
                  -------
this Agreement shall be in writing and shall be given by the means, and to the
addresses, set forth in the "Notices" section of the Reorganization Agreement.

     Section 9.6  Successors and Assigns.  This Agreement may not be assigned by
                  ----------------------
either party without the prior written consent of the other party, and any
attempt to assign any rights or obligations hereunder without such consent shall
be void.  This Agreement shall inure to the

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benefit of, and be binding upon and enforceable against the respective
successors and permitted assigns of the parties hereto.

     Section 9.7  Entire Agreement; Parties in Interest.  This Agreement, the
                  -------------------------------------
schedules hereto (if any) and any applicable provisions of the Reorganization
Agreement and the Ancillary Agreements comprise the entire agreement between the
parties hereto as to the subject matter hereof and supersede all prior
agreements and understandings between them relating to the subject matter
hereof, and, except as explicitly provided, are not intended to confer upon any
person other than the parties hereto (including their successors and permitted
assigns) any rights or remedies.

     Section 9.8  Overlap with Other Agreements.  If both (i) the provisions of
                  -----------------------------
this Agreement and (ii) the provisions of the Reorganization Agreement or any
Ancillary Agreement are by their terms applicable, then both the provisions of
this Agreement and such other agreement shall apply, but if the provisions of
this Agreement and such other agreement are in conflict, then (with respect to
matters subject to this Agreement) the provisions of this Agreement shall
control.

     Section 9.9  Severability.  If any term or provision of this Agreement or
                  ------------
the application thereof to any person or circumstance shall to any extent be
invalid or unenforceable, the remainder of this Agreement or the application of
such terms or provisions to persons or circumstances other than those as to
which it is invalid or unenforceable shall not be affected thereby and each term
and provision of this Agreement shall be valid and enforced to the fullest
extent permitted by law.

     Section 9.10  Captions. Captions and headings are supplied herein for
                   --------
convenience only and shall not be deemed a part of this Agreement for any
purpose.

     Section 9.11  Governing Law.  This Agreement shall be governed by and
                   -------------
construed in accordance with the internal substantive laws of the Commonwealth
of Massachusetts, without giving effect to the principles of conflicts of laws
thereof.

     Section 9.12  Counterparts.  This Agreement may be executed in several
                   ------------
counterparts, and all counterparts so executed shall constitute one agreement,
binding upon the parties hereto, notwithstanding that the parties are not
signatory to the same counterpart.

                                 [End of Text]

                                       12
<PAGE>

     IN WITNESS WHEREOF, Parent and Sub have caused this Agreement to be duly
executed by their authorized representatives as an agreement under seal as of
the date first written above.

                                    PARENT:

                                    Arthur D. Little, Inc., a Massachusetts
                                    corporation

                                    By: /s/ Mark A. Brodsky
                                       ----------------------------------
                                       Name: Mark A. Brodsky
                                       Title: Executive Vice President

                                    SUB:

                                    c-quential, Inc., a Delaware corporation

                                    By: /s/ Lorenzo C. Lamadrid
                                       ----------------------------------
                                       Name: Lorenzo C. Lamadrid
                                       Title: Director

                                       13<PAGE>

                                                                   EXHIBIT 10.11

                            STOCK PURCHASE AGREEMENT
                            (Additional Stockholders)

         THIS STOCK PURCHASE AGREEMENT (this "Agreement") is dated as of
February 1, 1999 by and among Arthur D. Little International, Inc., a
Massachusetts corporation ("Buyer"), and Simon C. Fawthrop, Simon C. Turpin,
Martin Malden and J. Gerard MacNamee (collectively, the "Additional
Stockholders").

         WHEREAS, the Additional Stockholders own of record and beneficially an
aggregate of 1,096 "C" shares, one penny each (said shares being referred to
herein as the "Company Shares") of the capital stock of Contactica Limited, a
United Kingdom limited company (the "Company");

         WHEREAS, the Additional Stockholders desire to sell all of the Company
Shares to Buyer, and Buyer desires to purchase all of the Company Shares; and

         WHEREAS, pursuant to a Stock Purchase Agreement dated the date hereof
(the "PS Agreement") among Buyer and Paul Berriman, Alvin Botting and Malcolm
Way (collectively, the "Principal Stockholders" and collectively with the
Additional Stockholders, the "Selling Stockholders"), the Principal Stockholders
are selling all of their shares in the Company to Buyer.

         NOW, THEREFORE, in order to consummate said purchase and sale and in
consideration of the mutual agreements set forth herein, the parties hereto
agree as follows:

ARTICLE 1. SALE OF SHARES AND PURCHASE PRICE.

         1.1 Transfer of Company Shares. Subject to the terms and conditions set
forth in this Agreement, at the Closing, each Additional Stockholder shall sell
with full title guarantee to the Buyer the number of Company Shares set forth
opposite his name in Exhibit A and shall deliver or cause to be delivered to
Buyer duly executed stock transfer forms and certificates representing such
Company Shares, together with such other documents as may be reasonably required
by Buyer to effect a valid transfer of such Company Shares by such Additional
Stockholder, free and clear of any and all liens, encumbrances, charges or
claims.

         1.2      Purchase Price and Payment.

                 (a) Subject to the satisfaction of all of the conditions
contained herein, in consideration of the sale by the Additional Stockholders to
Buyer of the Company Shares and in reliance upon the representations and
warranties of the Additional Stockholders herein contained and made at the
Closing, Buyer will pay to the Additional Stockholders an aggregate of Three
Hundred Twenty Two Thousand Five Hundred Forty-eight English Pounds
(pounds) 322,548) as set forth in this Section 1.2 (the "Purchase Price"), net
of the amounts funded by

<PAGE>

Buyer pursuant to Section 1.2(b) in respect of the exercise price of the options
previously held by the Additional Stockholders to purchase shares of the
Company=s capital stock.

                  (b) At the Closing, Buyer will pay to the Additional
Stockholders an aggregate of fifty percent (50%) of the Purchase Price by
delivering to each Additional Stockholder the amount specified opposite such
Additional Stockholder's name in Exhibit A hereto by bank cashier check or by
wire transfer of immediately available funds. Such payment will be net of the.
exercise price for the options held by each such Additional Stockholder, as set
forth in Exhibit A, which amounts shall be funded by Buyer on behalf of each
such Additional Stockholder and paid directly to the Company.

                  (c) The remaining fifty percent (50%) of the Purchase Price
shall be paid in equal installments over a three year period on each of the
first three anniversary dates of the Closing, subject to the conditions set
forth in this paragraph (c). Such installments shall be paid pro rata to each
Additional Stockholder (in accordance with his percentage ownership of the
Company Shares) in a combination of cash and common stock of Arthur D. Little,
Inc. ("ADL"), provided that (x) such Additional Stockholder shall not have been
dismissed for gross misconduct (as defined in Buyer's employee handbook) as an
employee of Buyer or another subsidiary of ADL on such anniversary date; (y)
such Additional Stockholder shall, not have voluntarily terminated his
employment with Buyer or another subsidiary of ADL on or prior to such
anniversary date; and (z) with respect to the ten percent (10%) portion of the
Purchase Price to be paid in ADL stock to the Additional Stockholders on the
third anniversary date (the "Contingent Stock"), the conditions of sub-clause
(ii) below shall be met on such anniversary date.

                           (i) For the avoidance of doubt, an Additional
                  Stockholder shall not forfeit his right to receive any such
                  installment if such Additional Stockholder's employment with
                  Buyer or another subsidiary of ADL is terminated due to death
                  or permanent disability. For purposes of this Section 1.2(c),
                  "permanent disability" means that such Additional Stockholder
                  is incapable of any future continued employment with Buyer or
                  another subsidiary of ADL, the existence of such inability
                  being determined by an independent physician agreed to by
                  Buyer and such Additional Stockholder.

                           (ii) Each Additional Stockholder shall be paid his
                  pro rata share of the Contingent Stock if on the third
                  anniversary date (in addition to the requirements of clauses
                  (x) and (y) above being satisfied with respect to such
                  Additional Stockholder), ADL or any direct or indirect
                  subsidiary thereof (including the Company) shall continue to
                  employ at least fifty percent (50%) of the employees of the
                  Company listed on Schedule 1.2(c)(ii) to the PS Agreement. For
                  purposes of this sub-clause (ii), employees who are hired to
                  replace any employee listed on such Schedule shall be counted
                  in order to determine whether the foregoing requirement has
                  been met. Prior to the third anniversary of the date hereof,
                  Buyer shall not, and shall procure that no other

                                       2
<PAGE>

                  subsidiary of ADL shall, make any material change to the
                  business of the Company, the result of which shall materially
                  adversely affect the Additional Stockholders' opportunity to
                  be paid the Contingent Stock.

                           (iii) The allocation of cash and stock (based on the
                  total Purchase Price) shall be as follows:

         One Year Anniversary - ten percent (10%) cash and three and one-half
percent (3.5%) ADL stock
         Two Year Anniversary - ten percent (10%) cash and three and one-half
percent (3.5%) ADL stock
         Three Year Anniversary - ten percent (10%) cash and three percent (3%)
ADL stock
         Three Year Anniversary - ten percent (10%) ADL stock (the Contingent
Stock)

         The ADL common stock shall be valued at fair market value. For purposes
of this Section 1.2(c), "fair market value" shall be the average of the fair
market value per share of the ADL common stock established by the Trustees of
the Arthur D. Little, Inc. Employees MDT Retirement Plan and the Trustees of the
Arthur D. Little, Inc. Employee Stock Ownership Plan, respectively, as of the
June 30 or December 31 immediately preceding such anniversary date. The ADL
common stock to be issued to the Principal Stockholders shall be subject to the
terms and conditions of a plan to be established by ADL, substantially the same
in form and substance to the plan attached hereto as Exhibit B.

         1.3 Time and Place of Closing. The closing of the purchase and sale
provided for in this Agreement (herein called the "Closing") shall be held at
the offices of Cambridge Consultants Limited, Science Park, Milton Road,
Cambridge CB4 0DW on February 1, 1999 or at such other place or an earlier or
later date or time as may be mutually agreed upon by the parties.

         1.4 Further Assurances. The Additional Stockholders from time to time
after the Closing at the request and expense of Buyer and without further
consideration shall execute and deliver further instruments of transfer and
assignment and take such other action as Buyer may reasonably require to more
effectively transfer and assign to, and vest in, Buyer the Company Shares and
all rights thereto, and to fully implement the provisions of this Agreement.

ARTICLE 2. REPRESENTATIONS AND WARRANTIES OF ADDITIONAL STOCKHOLDERS.

         As a material inducement to Buyer to enter into this Agreement and
consummate the transactions contemplated hereby, each Additional Stockholder
hereby severally makes to Buyer each of the representations and warranties set
forth in this Article 2 with respect to such Additional Stockholder. No
Additional Stockholder shall have any right of indemnity or

                                       3
<PAGE>

contribution from the Company or any subsidiary of the Company (each a
"Subsidiary" and collectively, "Subsidiaries") with respect to the breach of any
representation or warranty hereunder.

         2.1 Company Shares. Such Additional Stockholder owns of record and
beneficially the number of the Company Shares set forth opposite such Additional
Stockholder's name in Exhibit A. Such Company Shares are, and when delivered by
such Additional Stockholder to Buyer pursuant to this Agreement will be, duly
and validly issued, fully paid and free and clear of any and all liens,
encumbrances, charges or claims.

         2.2 Authority. Such Additional Stockholder has full right, authority,
power and capacity to enter into this Agreement and each agreement, document and
instrument to be executed and delivered by or on behalf of such Additional
Stockholder pursuant to this Agreement and to carry out the transactions
contemplated hereby and thereby. This Agreement and each agreement, document and
instrument executed and delivered by such Additional Stockholder pursuant to
this Agreement constitutes a valid and binding obligation of such Additional
Stockholder, enforceable in accordance with their respective terms, and such
Additional Stockholder has full power and authority to transfer, sell and
deliver his Company Shares to Buyer pursuant to this Agreement. The execution,
delivery and performance of this Agreement and each such agreement, document and
instrument:

              (i) does not and will not violate any laws of the United Kingdom
or other jurisdiction applicable to such Additional Stockholder, or require such
Additional Stockholder to obtain any approval, consent or waiver from, or make
any filing with, any person or entity (governmental or otherwise) that has not
been obtained or made; and

              (ii) does not and will not result in a breach of, constitute a
default under, accelerate any obligation under, or give rise to a right of
termination of, any indenture or loan or credit agreement or any other
agreement, instrument, lease, permit, authorization, order, judgment,
injunction, decree, determination or arbitration award to which, such Additional
Stockholder is a party or by which the property of such Additional Stockholder
is bound or affected, or result in the creation or imposition of any mortgage,
pledge, lien, security interest or other charge or encumbrance on the Company
Shares owned by such Additional Stockholder.

         2.3 Finder's Fee. Such Additional Stockholder has not incurred or
become liable for any broker's commission or finder's fee relating to or in
connection with the transactions contemplated by this Agreement.

         2.4 Agreements. Such Additional Stockholder is not a party to any
non-competition, trade secret or confidentiality agreement with any party other
than the Company or a Subsidiary. Other than the employment agreement between
such Additional Stockholder and the Company and the option granted to such
Additional Stockholder by the Company, there are no agreements or arrangements
to which such Additional Stockholder is a party relating to the

                                       4
<PAGE>

business of the Company or any Subsidiary or to such Additional Stockholder's
rights and obligations as a stockholder, director or officer of the Company or
any Subsidiary. Such Additional Stockholder does not own, directly or
indirectly, on an individual or joint basis, any material interest in, or serve
as an officer or director of, any customer, competitor or supplier of the
Company or any Subsidiary, or any organization which has a contract or
arrangement with the Company or any Subsidiary. Such Additional Stockholder has
not at any time transferred any of the stock of the Company or any Subsidiary
held by or for such holder to any employee of the Company or any Subsidiary,
which transfer constituted or could be viewed as compensation for services
rendered to the Company or any Subsidiary by said employee. The execution,
delivery and performance of this Agreement will not violate or result in a
default or acceleration of any obligation under any contract, agreement,
indenture or other instrument involving the Company or any Subsidiary to which
such Stockholder is a party.

ARTICLE 3.

Intentionally omitted.

ARTICLE 4. REPRESENTATIONS AND WARRANTEES OF BUYER.

         4.1 Making of Representations and Warranties. As a material inducement
to the Additional Stockholders to enter into this Agreement and consummate the
transactions contemplated hereby, Buyer hereby makes the representations and
warranties to the Additional Stockholders contained in this Article 4.

         4.2 Organization of Buyer. Buyer is a corporation duly organized,
validly existing and in good standing under the laws of the Commonwealth of
Massachusetts with full corporate power to own or lease its properties and to
conduct its business in the manner and in the places where such properties are
owned or leased or such business is conducted by it.

         4.3 Authority of Buyer. Buyer has full right, authority and power to
enter into this Agreement and each agreement, document and instrument to be
executed and delivered by Buyer pursuant to this Agreement and to carry out the
transactions contemplated hereby. The execution, delivery and performance by
Buyer of this Agreement and each such other agreement, document and instrument
have been duly authorized by all necessary corporate action of Buyer and no
other action on the part of Buyer is required in connection therewith. This
Agreement and each other agreement, document and instrument executed and
delivered by Buyer pursuant to this Agreement constitute, or when executed and
delivered will constitute, valid and binding obligations of Buyer enforceable in
accordance with their terms.

         4.4 Finder's Fee. Buyer has not incurred or become liable for any
broker's commission or finder's fee relating to or in connection with the
transactions contemplated by this Agreement.

                                       5
<PAGE>

ARTICLE 5. CONDITIONS.

         5.1 Conditions to the Obligations of Buyer. The obligation of Buyer to
consummate this Agreement and the transactions contemplated hereby are subject
to the fulfillment, prior to or at the Closing, of the following conditions
precedent:

              (a) Releases. Each Additional Stockholder shall have delivered to
Buyer a general release signed by such Additional Stockholder of all claims
which he may have against the Company and any Subsidiary in the form attached
hereto as Exhibit C.

              (b) PS Agreement. Immediately prior to the Closing, the Principal
Stockholders shall have executed and delivered the PS Agreement to Buyer.

              (c) Exercise of Options. Immediately after the execution and
delivery of the PS Agreement to Buyer, each Additional Stockholder shall have
exercised all options held by such Additional Stockholder to purchase shares of
the Company's capital stock, provided that Buyer shall fund such exercise price
on each such Additional Stockholder's behalf pursuant to Section 1.2(b) hereof.

ARTICLE 6. RIGHTS AND OBLIGATIONS SUBSEQUENT TO CLOSING.

         6.1 Survival of Warranties. Each of the representations, warranties,
agreements, covenants and obligations herein or in any schedule, exhibit,
certificate or financial statement delivered by any party to the other party
incident to the transactions contemplated hereby are material, shall be deemed
to have been relied upon by the other party and shall survive the Closing
regardless of any investigation and shall not merge in the performance of any
obligation by either party hereto.

ARTICLE 7. INDEMNIFICATION AND OTHER CLAIMS.

         7.1 Indemnification by the Additional Stockholders. Without restricting
the rights of Buyer or otherwise affecting the ability of Buyer to claim damages
on any other basis available to it, each of the Additional Stockholders,
severally and not jointly, agrees subsequent to the Closing to indemnify and
hold the Company, the Subsidiaries, Buyer and their respective subsidiaries and
affiliates and persons serving as officers, directors, partners or employees
thereof (individually a "Buyer Indemnified Party" and collectively the "Buyer
Indemnified Parties") harmless from and against any damages, liabilities,
losses, taxes, fines, penalties, costs, and expenses (including, without
limitation, reasonable fees of counsel) of any kind or nature whatsoever
(whether or not arising out of third-party claims and including all amounts paid
in investigation, defense or settlement of the foregoing) which may be sustained
or suffered by any of them arising out of or based upon fraud or fraudulent
misrepresentation by the Additional Stockholder.

                                       6
<PAGE>

         7.2 Limitations on Liability of the Additional Stockholders.
Notwithstanding any provision of this Agreement to the contrary:

              (a) No damages shall be payable to Buyer for any claim or claims
for breach of any representation or warranty made under this Agreement or in any
schedule or exhibit delivered pursuant hereto (each, a "Breach"), unless the
total of all claims (together with any claims for indemnification made pursuant
to Section 7.1) shall exceed (pounds)1,500 in the aggregate, whereupon the full
amount of such claims shall be recoverable in accordance with the terms hereof.

              (b) The aggregate liability of each Additional Stockholder to
Buyer with respect to claims for damages as the result of a Breach shall not
exceed such Additional Stockholder's pro rata portion of the Purchase Price.

              (c) Except in respect of indemnification claims made pursuant to
Section 7.1, no Additional Stockholder shall have any liability in respect of
claims for indemnification or damages unless written notice of such claim, in
accordance with the provisions of Section 7.4, shall have been given to such
Additional Stockholder on or before the eighteen (18) month anniversary of this
Agreement.

              (d) As applicable, the limitations on liability set forth in
Section 10.2 of the PS Agreement shall apply with respect to an Additional
Stockholder's obligations hereunder.

         7.3 Claims against Buyer. An Additional Stockholder may bring an action
against Buyer for Breach subject to the following provisions:

              (a) No damages shall be payable to an Additional Stockholder for
any claim or claims of Breach unless the total of all such claims shall exceed
,1,500 in the aggregate, whereupon the full amount of such claims shall be
recoverable in accordance with the terms hereof.

              (b) The aggregate liability of Buyer to each Additional
Stockholder with respect to claims for Breach shall not exceed the amount paid
by Buyer to such Additional Stockholder hereunder.

              (c) Buyer shall not have any liability in respect of claims for
damages unless written notice of such claim, specifying the circumstances giving
rise to such claim and, to the extent reasonably possible, the amount thereof,
shall have been given to Buyer on or before the eighteen (18) month anniversary
of this Agreement.

              (d) As applicable, the limitations on liability set forth in
Section 10.4 of the PS Agreement shall apply with respect to Buyer's obligations
hereunder.

                                       7
<PAGE>

         7.4 Notice; Defense of Claims. A party (including, for purposes of this
Section 7.4, a Buyer Indemnified Party) may make claims for indemnification or
damages hereunder by giving written notice thereof to the responsible party
within the period in which such claims can be made hereunder. If indemnification
or damages is sought for a claim or liability asserted by a third party, the
claiming party shall also give written notice thereof to the responsible party
promptly after it receives notice of the claim or liability being asserted, but
the failure to do so shall not relieve the responsible party from any liability
except to the extent that it is prejudiced by the failure or delay in giving
such notice. Such notice shall summarize the bases for the claim and any claim
or liability being asserted by a third party. Within 20 days after receiving
such notice the responsible party shall give written notice to the claiming
party stating whether it disputes the claim and whether it will defend against
any third party claim or liability at its own cost and expense. If the
responsible party fails to give notice that it disputes a claim within 20 days
after receipt of notice thereof, it shall be deemed to have accepted and agreed
to the claim, which shall become immediately due and payable. The responsible
party shall be entitled to direct the defense against a third party claim or
liability with counsel selected by it (subject to the consent of the claiming
party, which consent shall not be unreasonably withheld) as long as the
responsible party is conducting a good faith and diligent defense. The claiming
party shall at all times have the right to fully participate in the defense of a
third party claim or liability at its own expense directly or through counsel;
provided, however, that if the named parties to the action or proceeding include
both the responsible party and the claiming party and the claiming party is
advised that representation of both parties by the same counsel would be
inappropriate under applicable standards of professional conduct, the claiming
party may engage separate counsel at the expense of the responsible party. If no
such notice of intent to dispute and defend a third party claim or liability is
given by the responsible party, or if such good faith and diligent defense is
not being or ceases to be conducted by the responsible party, the claiming party
shall have the right, at the expense of the responsible party, to undertake the
defense of such claim or liability (with counsel selected by the claiming
party), and to compromise or settle it, exercising reasonable business judgment.
If the third party claim or liability is one that by its nature cannot be
defended solely by the responsible party, then the claiming party shall make
available such information and assistance as the responsible party may
reasonably request and shall cooperate with the responsible party in such
defense, at the expense of the responsible party.

         7.5 Satisfaction of Additional Stockholder Payment Obligations. In
order to satisfy the payment obligations of any Additional Stockholder pursuant
to Sections 7.1 and 7.2 above, a Buyer Indemnified Party shall have the right
(in addition to collecting directly from such Additional Stockholder) to set off
its indemnification claims against any and all amounts due to such Additional
Stockholders pursuant to Section 1.2(c) hereof.

ARTICLE 8. MISCELLANEOUS.

         8.1 Fees and Expenses. Buyer and the Additional Stockholders will each
bear their own expenses in connection with the negotiation and the consummation
of the transactions

                                       8
<PAGE>

contemplated by this Agreement, and no expenses of the Additional relating in
any way to the purchase and sale of the Company Shares hereunder and the
transactions contemplated hereby shall be charged to or paid by the Company, any
Subsidiary or Buyer.

         8.2 Governing Law. This Agreement shall be construed under and governed
by the internal laws of England without regard to its conflict of laws
provisions. Each of the Additional Stockholders hereby submits to the exclusive
jurisdiction of the courts of England.

         8.3 Notices. Any notice, request, demand or other communication
required or permitted hereunder shall be in writing and shall be deemed to have
been given if delivered or sent by facsimile transmission, upon receipt, or if
sent by registered or certified mail, upon the sooner of the date on which
receipt is acknowledged or the expiration of three days after deposit in United
Kingdom or United States post office facilities properly addressed with postage
prepaid. All notices to a party will be sent to the addresses set forth below or
to such other address or person as such party may designate by notice to each
other party hereunder:

TO BUYER:            John F. Burns
                     Arthur D. Little International, Inc.
                     Acorn Park
                     Cambridge, MA 02140

With a copy to:      Sam Gallo, Esq.
                     Arthur D. Little, Inc.
                     Acorn Park
                     Cambridge, MA 02140

TO ADDITIONAL
STOCKHOLDERS:        At the name and address set forth on Exhibit A

Any notice given hereunder may be given on behalf of any party by its counsel or
other authorized representatives.

         8.4 Entire Agreement. This Agreement, including the Schedules and
Exhibits referred to herein and the other writings specifically identified
herein or contemplated hereby, is complete, reflects the entire agreement of the
parties with respect to its subject matter, and supersedes all previous written
or oral negotiations, commitments and writings. No promises, representations,
understandings, warranties and agreements have been made by any of the parties
hereto except as referred to herein or in such Schedules and Exhibits or in such
other writings; and all inducements to the making of this Agreement relied upon
by either party hereto have been expressed herein or in such Schedules or
Exhibits or in such other writings. Nothing in this clause shall operate to
exclude the liability of any party for fraudulent misrepresentation.

                                       9
<PAGE>

         8.5 Assignability; Binding Effect. This Agreement shall only be
assignable by Buyer to a corporation or partnership controlling, controlled by
or under common control with Buyer upon written notice to the Additional
Stockholders, provided that this Agreement shall be reassigned to Buyer if such
assignee ceases to be controlling, controlled by or under common control with
Buyer. This Agreement may not be assigned by the Additional Stockholders without
the prior written consent of Buyer. This Agreement shall be binding upon and
enforceable by, and shall inure to the benefit of, the parties hereto and their
respective successors and permitted assigns.

         8.6 Captions and Gender. The captions in this Agreement are for
convenience only and shall not affect the construction or interpretation of any
term or provision hereof. The use in this Agreement of the masculine pronoun in
reference to a party hereto shall be deemed to include the feminine or neuter,
as the context may require.

         8.7 Execution in Counterparts. For the convenience of the parties and
to facilitate execution, this Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which shall
constitute one and the same document.

         8.8 Amendments. This Agreement may not be amended or modified, nor may
compliance with any condition or covenant set forth herein be waived, except by
a writing duly and validly executed by each party hereto, or in the case of a
waiver, the party waiving compliance.

                                       10
<PAGE>

         IN WITNESS WHEREOF the parties hereto have caused this Agreement to be
executed as of the date set forth above by their duly authorized
representatives.

                                   ARTHUR D. LITTLE INTERNATIONAL, INC.

                                   By:
                                      ---------------------------------------
                                      Name:
                                      Title:

                                   ------------------------------------------
                                   Simon C. Fawthrop

                                   ------------------------------------------
                                   Simon C. Turpin

                                   ------------------------------------------
                                   Martin Malden

                                   ------------------------------------------
                                   J. Gerard MacNamee

                                       11
<PAGE>

                                    Exhibit A

     List of Additional Stockholders, Holdings and Consideration to be Paid

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------------------------

                                               CONSIDERATION PAYABLE BY BUYER
--------------------------------------------------------------------------------------------------------------------
                                               OPTION EXERCISE                       NET AGGREGATE CONSIDERATION
NAME AND ADDRESS OF           COMPANY SHARES   PRICE FUNDED       NET CASH           PAYABLE IN CASH/STOCK OVER
ADDITIONAL STOCKHOLDER        OWNED            BY BUYER           AT CLOSING         FIRST THREE ANNIVERSARIES
--------------------------------------------------------------------------------------------------------------------
<S>                           <C>              <C>                <C>                <C>
Simon C. Fawthrop             274 "C"          (pounds)1,332.50   (pounds)39,652.50         (pounds)39,652

--------------------------------------------------------------------------------------------------------------------
Simon C. Turpin               274 "C"          (pounds)2,460      (pounds)39,089            (pounds)39,088

--------------------------------------------------------------------------------------------------------------------
Martin Malden                 274 "C"          (pounds)2,460      (pounds)39,089            (pounds)39,088

--------------------------------------------------------------------------------------------------------------------
J. Gerard MacNamee            274 "C"          (pounds)2,460      (pounds)39,089             (pounds)39,088

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

</TABLE>

                                       12
<PAGE>

                                    Exhibit B

                             Arthur D. Little, Inc.

                           CSC Stock Acquisition Plan

         1. Purpose. The purpose of the ARTHUR D. LITTLE, INC. CSC STOCK
ACQUISITION PLAN (the "Plan") is to enable Arthur D. Little, Inc. ("ADL") and
its subsidiary, Arthur D. Little (Schweiz)AG to acquire certain assets and
business of __________________________ , and to provide consideration under the
Stock Purchase Agreement and the Performance Agreement executed by
______________________________ and ADL dated March 31, 1998, and to secure for
_________________________ the benefits arising from ownership of the common
stock of ADL ("Common Stock") as it is expected that _____________ will
contribute to ADL's future growth and success.

         2. Shares of Stock Subject to Plan. A maximum of shares of Common Stock
(the "Shares") may be issued pursuant to the Plan.

         3. Eligibility. ______________________ is the only eligible participant
in the Plan (the "Participant").

         4. Purchase Agreement. The Participant in the Plan shall enter into a
Purchase Agreement or other agreement with ADL (the "Purchase Agreement.") and
shall execute such other agreements and other instruments as ADL deems necessary
or desirable, in each case in such form and upon such terms, consistent with the
Plan, as may be approved by the Chief Executive Officer of ADL.

         5. Eligible Shares. The Participant shall be issued that number of
shares as is set forth on Schedule I attached to and made a part of this Plan.

         6.       Securities Act Limitations.

               (a) The Employee represents that he or she is not a "U.S. person"
within the definition set forth in Rule 902(0) (1) of Regulation S under the
Securities Act (the "Securities Act"), and is not acquiring the Shares for the
account or benefit of a "U.S. person". A U.S. person includes certain entities
and any natural person resident in the United States.

               (b) All offers, sales and issuance of Eligible Shares under the
Plan will be made by ADL pursuant to exemptions from registration available
under the Securities Act of 1933, as amended (the "Securities Act"), including,
in the case of certain United States Employees, Rule 701 under the Securities
Act ("Available Exemptions"). The aggregate number of Eligible Shares offered
and sold in any Offering Period that are not offered pursuant to Regulation S
under the Securities Act and that are offered to participants who are not

                                       13
<PAGE>

"Accredited Investors" within the meaning of Regulation D under the Securities
Act ("U.S. NonAccredited Investors") shall be limited to the maximum number that
can be offered and sold under Rule 701 as determined by ADL.

         7. Maximum Ownership. No Participant may be issued Shares under the
Plan to the extent that such issuance will result in such Participant owning
directly, indirectly, or beneficially over 2% of the total number of shares of
ADL Common Stock outstanding, which percentage shall include any options to
purchase ADL Common Stock and any ADL Common Stock held by such Participant, in
all plans of ADL in which the Participant participates.

         8. Issuance Price. The "Issuance Price" at which Shares shall be issued
under the Plan shall be equal to the average of the Fair Market Value per share
of common stock of ADL as established by the Trustees of the Memorial Drive
Trust, and the Fair Market Value established by the Trustees of the ESOP as of
December 31, 1997 (US $_____/share).

         9. Treasury Shares. ADL intends to issue the shares necessary for this
Plan from the Treasury.

         10. Repurchase of Shares. Upon the termination of the Participant's
employment or relationship with ADL, or any of its subsidiaries, for any reason
whatsoever (including death or disability), such Participant (or his or her
beneficiary or estate) shall sell to ADL, and ADL shall purchase, all of the
Shares issued to such Participant under the Plan at a price equal to the
Adjusted Fair market Value determined as of the semiannual valuation date next
following the date of termination of the Participant's employment or
relationship, or determined as of June 30 or December 31 if a Participant's
employment or relationship terminates on June 30 or December 31, respectively
(or if no such Adjusted Fair Market Value has been established within 12 months
after such termination, then such Adjusted Fair Market Value may be determined
in good faith by the Board of Directors of ADL). For this purpose, Adjusted Fair
Market Value shall also include an amount equal to any cash dividend paid
between such termination of employment or relationship with ADL and the
applicable semiannual valuation date. The effective date of such repurchase
shall be the date of termination of employment or relationship, notwithstanding
that the repurchase price shall be determined after such date of termination.
The repurchase price shall be paid within 90 days following the date on which
the repurchase price shall have been determined.

         11. Attainment of Age 55. If the Participant attains the age of 55
while employed by ADL, such Participant shall have the right to require ADL to
purchase from such Participant in any calendar year up to 20% of the Shares
owned by the Participant under the Plan (determined in the manner provided in
the following sentence). This right shall apply only to up to 20% of the Shares
held at the time the Participant first exercises this right, and this right may
be exercised by the Participant once per calendar year at least 30 days before
the June 30 or December 31 semiannual valuation dates. This right may not be
exercised on a cumulative basis. However, once a Participant exercises the right
granted under this Section 11, the Participant shall not be allowed to make any
further purchases under any other stock purchase

                                       14
<PAGE>

plan of ADL in which the Participant participates. The effective date of such
repurchase shall be the date on which the right is exercised. The purchase price
for any Shares purchased by ADL shall be the Adjusted Fair Market Value as of
the semiannual valuation date next following the exercise of such right,
including cash dividends paid between the exercise of the right and such
semiannual valuation date. The repurchase price shall be paid within 90 days
following the date on which the repurchase price shall have been determined.

         12. Omitted

         13. Restrictions on Transfer. A Participant may not sell, transfer,
pledge, hypothecate, assign, or otherwise dispose of any of the Shares, or any
interest therein, whether voluntarily or by operation of law, other than to ADL
pursuant to the Plan or otherwise in accordance with ADL policies as from time
to time in effect.

         14. Legends Upon Certificates. The certificates representing the Shares
shall bear appropriate legends evidencing the terms and provisions of the Plan,
as well as any restrictions upon transfer, if any, under applicable federal,
state and foreign securities laws.

         15. Escrow Arrangements. ADL reserves the right to hold in escrow the
certificates representing the Shares issued pursuant to the Plan. ADL may act as
its own escrow agent or appoint a third party to act in such capacity. The
Participant shall execute such agreements and other instruments as may be deemed
necessary or desirable by the Chief Executive Officer of ADL or his designee in
connection with such escrow arrangements.

         16. Currencies.

               (a) ADL shall designate the currencies to be included in a
"Market Basket" of currencies (the "Market Basket"). Upon becoming a Participant
in the Plan, each Participant shall designate an applicable Market Basket
currency, in accordance with the following provisions:

                           (i)      any Participant may designate U.S. Dollars;

                           (ii) a Participant may designate the currency of the
                  country in which the Participant is assigned if such currency
                  is in the Market Basket; and

                           (iii) a Participant may designate the currency of the
                  country of which such Participant is a citizen if such
                  currency is in the Market Basket.

No Participant may change his or her currency designation unless (x) such change
is approved in writing by the Chief Executive Officer of ADL or (y) the
Participant's designated currency is removed from the Market Basket, in which
case such Participant shall designate a new currency in accordance with this
paragraph (a).

                                       15
<PAGE>

               (b) As of each semi-annual valuation date, ADL shall determine an
Adjustment Rate applicable to each currency included in the Market Basket (the
"Adjustment Rate"). The Adjustment Rate will equalize the effect of exchange
rate fluctuations on stock appreciation during the six-month period preceding
the semiannual valuation date for each currency in the Market Basket. As of each
semi-annual valuation date, each Participant's account will be adjusted on the
basis of the Fair Market Value as defined herein and also adjusted based on the
Adjustment Rate determined by ADL, and an Adjusted Fair Market Value for each
Participant's account will be calculated by ADL.

               (c) The amount payable by ADL to a Participant for the repurchase
of shares under Section 10 above shall be payable, at the option of the
Participant, in either the local currency of the country in which the
Participant is employed by ADL or in U.S. Dollars. If the payment of the
repurchase price is made in local currency, such local currency shall be
converted into U.S. Dollars based on the Actual Exchange Rate as published by
the Wall Street Journal as of June 30 for repurchases between January 1 and June
30, and as of December 31 for repurchases between July 1 and December 31.

         17. Compliance with Foreign Laws. ADL may establish additional
conditions or provisions for the participation of eligible employees in order to
comply with the tax, securities, exchange regulations, and other laws and
regulations of the countries in which such employees reside.

         18. Amendment or Termination. This Plan may be amended from time to
time by vote of a majority of the Board of Directors of ADL. However, no
amendment shall reduce any rights of the Participant with regard to shares which
have already been issued under the Plan. In the event of termination, all the
outstanding Purchase Agreements will remain in effect in accordance with their
terms.

                                           ----------------------------------
                                           Chief Executive Officer

Effective Date: April 24, 1998

Confirmed and ratified by the
Board of Directors on April 24, 1998

                                           ----------------------------------
                                           Corporate Secretary

                                       16
<PAGE>

                                 DEED OF RELEASE
                                 ---------------

To:  The Directors of Contactica Limited, Contactica Asia Limited, and
     Contactica Inc. (each of which is referral to in this letter as "the
     Company")

                                                          Dated: 1 February 1999

Dear Sirs

Save for accrued employment rights and accrued remuneration I hereby:

1    confirm that there is no indebtedness due or contingently due (whether by
     way of loan account or otherwise) from the Company to me and that no
     agreement or arrangement is outstanding under which any of the Company, its
     shareholders, directors, officers, employees or advisers has or might have
     any obligation (actual or contingent) to me on any account whatsoever; and

2    unconditionally release and discharge the Company, its shareholders,
     directors, officers, employees and advisers from any claim which I may have
     on any account whatsoever

IN WITNESS whereof this deed has been duly executed by the party and it is
delivered on but not before the day and year first before written

SIGNED as a deed and delivered by)
**                               )
in the presence of:              )

Witness' Signature:

Witness' Name:

Address:

Occupation:

                                       17

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