<PAGE>

                                                                    EXHIBIT 10.8

                              Investment Agreement
                              --------------------
                           (Series C Preferred Stock)

     THIS IS AN INVESTMENT AGREEMENT (this "Agreement") made and dated as of
June 25, 1998,

among:    Greenwich Technology Partners, inc., a Delaware corporation (the
-----
          "Corporation");

          FG-GTPC, a Florida partnership, (the "Investor");

and:      those additional parties, if any, identified as "Other Investors" on
          the
          ---
          signature pages of this Agreement (collectively, with the Investor,
          the "Series C Investors").

     The Corporation and the Series C Investors agree as follows:

     1.  DEFINITIONS.  As used in this Agreement, each of the following terms
         -----------
means:

          "Affiliate":  With respect to any particular Person, any other Person
directly or indirectly, controlling, controlled by or under common control with
such Person.

          "Books and Records":  The books and records of the Corporation.

          "Business":  The computer networking and related consulting business
conducted by the Corporation.

          "Corporation":  Greenwich Technology Partners, Inc., a Delaware
corporation.

          "Environmental Laws":  All Laws governing the use, storage, shipment,
handling, disposal, discharge, release, cleanup, reporting, labelling, warning,
workplace disclosure or monitoring of Hazardous Materials, or otherwise relating
to environmental pollution or environmental protection, including, as may be
applicable to environmental matters, the common law respecting nuisance,
trespass, tortious liability and strict liability.

          "Financial Statements":  The Corporation's balance sheet as at
December 31, 1997 and the related statements of income, retained earnings and
changes in financial position for such fiscal year, and the Corporation's
interim balance sheet as at March 31, 1998 and the related interim statements of
income, retained earnings and changes in financial position for the fiscal
quarter then ended.

          "Hazardous Materials":  All substances, in whatever form or
concentration, which are classified as hazardous, toxic or dangerous or as
pollutants or contaminants under any
<PAGE>

Environmental Laws. "Hazardous Materials" specifically include gasoline, oil and
other petroleum products, their fractions and their constituent and residual
compounds and by-products, and radon, asbestos, lead-based paint,
ureaformaldehyde and PCB's. Where under applicable Environmental Laws a
jurisdiction exercises the authority to establish stricter requirements
regarding Hazardous Materials or to define Hazardous Materials more inclusively,
the stricter requirements and more inclusive definitions shall apply with
respect to the operations of the Business which are located or conducted within
such jurisdiction or which are otherwise subject to its authority.

          "Laws":  All laws, statutes, ordinances, rules, regulations and other
requirements having the force of law promulgated by any governmental authority,
commission, agency or body which are applicable to the Corporation or the
Business, in each case whether local, state, territorial, or federal.

          "Liabilities":  All liabilities or obligations of the Corporation of
any kind or description, whether accrued, absolute, contingent or otherwise.

          "Liens":  All liens, security interests, pledges, mortgages,
encumbrances, claims, charges, agreements and rights of others of any nature
whatsoever.

          "Losses":  Any loss (including loss in the value of any Series A
Shares), claim, liability, penalty, damage, cost or expense, whether direct or
indirect, special or consequential, including reasonable attorneys' fees.

          "Order":  Any order, writ, decree, ruling, award, injunction or other
directive or requirement having the force of law issued by any court, tribunal,
administrative agency, other governmental authority, or arbitrator, in each case
whether local, state, territorial or federal which is applicable to the
Corporation.

          "Person":  Any natural person, corporation, partnership (general,
limited or otherwise), limited liability company, trust, association, joint
venture, governmental body or agency or other entity having legal status of any
kind.

          "Preferred Shareholders":  As defined in Section 2.2.

          "Proceeding":  Any litigation, lawsuit, arbitration, mediation,
grievance, hearing, investigation or other legal, administrative, governmental
or private party proceeding or enforcement action.

          "Series A Shares":  Share of Series A Convertible Preferred Stock
having the rights, preferences, privileges, restrictions and other matters set
forth in Articles 4, 5 and 6 of the Restated Certificate of Incorporation of the
Corporation.

          "Series B Shares":  Shares of Series B Convertible Preferred Stock
having the rights, preferences, privileges, restrictions and other matters set
forth in Articles 4, 5 and 6 of the Restated Certificate of Incorporation of the
Corporation.

                                       2
<PAGE>

          "Series C Shares":  Shares of Series C Convertible Preferred Stock
having the rights, preferences, privileges, restrictions and other matters set
forth in Articles 4, 5 and 6 of the Restated Certificate of Incorporation of the
Corporation.

          "Shareholders Agreement":  As defined in Section 2.2.

     2.  PURPOSE AND BACKGROUND.
         ----------------------

          2.1.  Sale of Series C Shares.  The Corporation desires to sell to
                -----------------------
the Series C Investors that number of Series C Shares set forth opposite their
respective names on Schedule 2.1, and the Series C Investors desire to purchase
the Series C Shares from the Corporation, all on the terms and conditions set
forth in this Agreement.

          2.2.  Shareholders Agreement.  Concurrently with this Agreement, the
                ----------------------
Corporation, the Series C Investors and the holders of the Corporation's Series
A Shares and the Series B Shares (collectively, after giving effect to the
transactions contemplated by this Agreement, the "Preferred Shareholders") are
entering into a Shareholders Agreement (the "Shareholders Agreement") setting
forth, among other matters, certain restrictions on disposition of, and options
to purchase or sell, the Preferred Shareholders' respective shares of the
Corporation's Preferred Stock..

     3.  PURCHASE AND SALE OF SHARES, USE OF PROCEEDS.  Subject to the terms and
         --------------------------------------------
conditions contained in this Agreement.

          3.1.  Purchase of Series C Shares.  The Corporation hereby sells and
                ---------------------------
issues to the Series C Investors, and the Series C Investors hereby purchases
from the Corporation, the number of Series C Shares set forth opposite their
respective names on Schedule 2.1, free and clear of all Liens, for an aggregate
purchase price shown on Schedule 2.1, which is being paid concurrently with this
Agreement.

          3.2.  Use of Proceeds.  The Corporation shall use the proceeds from
                ---------------
the sale of the Series C Shares for working capital and general corporate
purposes, including the payment of legal fees and expenses of the Series C
Investors as provided in Section 12.6.

     4.  THE CORPORATION'S REPRESENTATIONS AND WARRANTIES.  The Corporation
         ------------------------------------------------
makes the following representations and warranties to the Series C Investors:

          4.1.  Organization and Authority.  The Corporation is a corporation
                --------------------------
duly organized, validly existing and in good standing under the Laws of
Delaware.  The Corporation has full corporate power and authority to own its
assets and to carry on the Business as presently conducted.  The Corporation is
duly qualified to do business as a foreign corporation and is in good standing
in Connecticut, New York and each other jurisdiction where the Corporation is
required to be so qualified.  The Corporation has no subsidiaries and owns no
capital stock or other equity interests in any Person.  The signing, delivery
and performance of this Agreement and the Shareholders Agreement have been duly
authorized by the Corporation's Board of

                                       3
<PAGE>

Directors and shareholders, and no further corporate or other action is required
on the part of the Corporation in order to authorize this Agreement or the
transactions contemplated by this Agreement. This Agreement is the legal, valid
and binding obligation of the Corporation, duly enforceable against the
Corporation in accordance with its terms.

          4.2.  Capitalization.  The Corporation's authorized capital stock
                --------------
consists solely of 46,666,666 shares, 30,000,000 of which shall be common stock,
par value $.01 per share and 16,666,666 of which shall be preferred stock, par
value $.01 per share.  4,100,000 of the authorized shares of preferred stock are
designated as Series A Preferred Stock, 5,723,000 of the authorized shares of
preferred stock are designated as Series B Preferred Stock, 6,666,666 of the
authorized shares of preferred stock are designated as Series C Preferred Stock
and 177,000 of the authorized shares of preferred stock are not designated as to
series.  The only shares of stock which are presently issued are 177,000 shares
of common stock, 4,100,000 shares of Series A Preferred Stock and 5,723,000
shares of Series B Preferred Stock.  Except as provided in the Certificate of
Incorporation and except for stock options granted to employees of the
Corporation which are set forth in Schedule 4.13, the Corporation has no shares
of capital stock reserved for issuance, and the Corporation has no outstanding
options, warrants, rights, calls or commitments relating to its shares of
capital stock or any outstanding securities or obligations convertible into or
exchangeable for, or giving any Person any right to subscribe for or acquire
from the Corporation, any shares of capital stock.  There are no preemptive or
other subscription rights with respect to any shares of capital stock.  All of
the shares of capital stock which are issued and outstanding have been duly
authorized and validly issued and are fully paid and are nonassessable.  The
Series C Shares to be issued to the Series C Investors pursuant to this
Agreement have been duly authorized and when issued, they will be validly
issued, fully paid and nonassessable.

          4.3.  No Conflict or Violation.  Neither the signing and delivery of
                ------------------------
this Agreement or the Shareholders Agreement by the Corporation nor the
performance by the Corporation of the transactions contemplated by this
Agreement or the Shareholders Agreement will result in:  (i) a violation of or
conflict with the Corporation's certificate of incorporation or bylaws; (ii) a
violation of any Laws or any Order to which the Corporation is subject; (iii)
the imposition of any material Lien against the Corporation's assets; or (iv)  a
breach or default under any mortgage, indenture, deed of trust, real property or
personal property lease, license, contract, or other agreement.

          4.4.  Financial Statements.  The Financial Statements present fairly
                --------------------
the financial condition and results of operations of the Corporation of and for
periods covered by the Financial Statements, subject only to ordinary course
adjustments for normal, recurring accruals resulting from the year-end audit.

          4.5.  Absence of Certain Changes or Events.  Since March 31, 1998, the
                ------------------------------------
Business has operated only in the ordinary course and there has been no:  (i)
material adverse change in the Business, the financial condition of the
Corporation, the results of operations of the Corporation or the prospects for
the Business; (ii) damage, destruction or loss (whether or not covered by
insurance) involving any of the Corporation's assets; (iii) sale or lease or
other disposition of any of the Corporation's assets, except for dispositions in
the ordinary course;

                                       4
<PAGE>

(iv) declaration or payment of any dividend or distribution on any shares of its
capital stock or other equity interests; (v) repurchase or other acquisition of
any shares of its capital stock or of any option, warrant, right, call or
commitment relating to shares of capital stock or other equity interests or any
outstanding securities convertible into shares of capital stock, or, except as
set forth in Schedule 4.13, any grant to any Person of any right to subscribe
for or acquire from it, any shares of capital stock or other equity interests;
(vi) the granting or creation by the Corporation of any material Lien affecting
any of the Corporation's assets; or (vii) to the Corporation's best knowledge,
any transaction by the Corporation outside the ordinary course of the Business.

          4.6.  Consents and Approvals.  The signing, delivery and performance
                ----------------------
by the Corporation of this Agreement and the transactions contemplated by this
Agreement do not require the consent, approval or authorization of, or any
declaration, filing, registration or notice with or to any governmental or
regulatory authority, or any other Person, except where the failure to obtain
such would not have a material adverse effect on the Corporation.

          4.7.  Material Agreements.  Schedule 4.7 contains a complete and
                -------------------
correct list, as of the date of this Agreement, of all agreements, contracts,
commitments, undertakings and other obligations, whether written or oral,
involving the Corporation or otherwise relating to the Business, which (i)
entail a commitment of $10,000 or more, or (ii) have a stated duration of one
(1) year or longer, or (iii) are not cancelable on thirty (30) days' notice or
less without penalty.  True and complete copies of all written agreements,
contracts and commitments listed in Schedule 4.7, including all amendments, have
been made available to the Series C Investors.

          4.8.  Absence of Litigation.  There is no material Proceeding which is
                ---------------------
either pending or, to the Corporation's best knowledge, threatened against the
Corporation or otherwise involving its assets or the Business, and there are no
outstanding Orders against the Corporation or with respect to the Business or
the Corporation's assets.

          4.9.  Compliance with Laws.  The Corporation is currently in
                --------------------
compliance and has in the past complied, in each case in all material respects,
with the Laws applicable to the Corporation, except where the failure to do so
would not have a material adverse effect on the Corporation.  The Corporation
has not received notice of violation or alleged violation of any Laws relating
to the conduct of the Business which has not been rectified or which remains
outstanding.

          4.10.  Accounts Receivable.  All accounts receivable reflected on the
                 -------------------
Financial Statements and all accounts receivable of the Business that have
arisen since the respective dates of the Financial Statements derive from bona
                                                                          ----
fide transactions in the ordinary course of the Business and are payable on
----
ordinary terms, less adequate reserves for doubtful accounts as reflected in the
Books and Records.  No person has asserted or threatened to assert any counter-
claims or offsetting claims or defenses to collection of the Corporation's
accounts receivable.  The Books and Records as of the date of this Agreement
reflect an accurate aging of all accounts receivable.  Except as stated in
Schedule 4.10, the Corporation is not aware that any of the accounts receivable
as of the date of this Agreement are uncollectible or are likely to be
uncollectible in the ordinary course within 60 days after origination.

                                       5
<PAGE>

          4.11.  Intellectual Property.  Schedule 4.11 is a true and complete
                 ---------------------
listing, as they relate to or are used in the Business, of all:  (i) trademark
registrations and applications in the United States, any state or any other
jurisdiction; (ii) common law or unregistered trademarks; (iii) tradenames, (iv)
patents and patent applications; (v) registered copyrights; and (vi) technical
know-how, license or similar agreements to which the Corporation with respect to
the Business is party, or from which the Business otherwise benefits
(collectively, the "Intellectual Property").  No proceedings are pending or, to
the Corporation's best knowledge, threatened, which challenge the validity of
the Corporation's ownership or use of the Intellectual Property.  All licensing
and similar agreements relating to the Intellectual Property are listed on
Schedule 4.11 and are in full force and effect, and there is no default by the
Corporation or any other party to such agreements.  The Corporation has not
received notice of conflict with the asserted rights of other Persons.  To its
best knowledge, the Corporation is not infringing any patents, trademarks or
copyrights and is not misappropriating or violating trade secrets or other
proprietary rights of any other Person.

          4.12.  Environmental Matters.  The Corporation is in compliance with
                 ---------------------
applicable Environmental Laws.  To the Corporation's best knowledge, there is no
past or existing event, condition, circumstance or practice or procedure
involving or relating to Hazardous Materials or other environmental matters
which might interfere with or adversely affect the conduct of the Business as
now being conducted, or which would require disclosure, reporting, monitoring,
cleanup, remediation or other action on the part of the Corporation or at the
Corporation's expense, or which might result in the Corporation's being in
violation of or in noncompliance with Environmental Laws.

          4.13.  Employees.  To the Corporation's best knowledge, the
                 ---------
Corporation has satisfied in full all of its obligations to date to its
employees, including obligations under employee benefits plans.  Except as
specified in Schedule 4.13, employees of the Business are employed "at will",
and, except as otherwise provided in this Agreement, the employment of each
employee may be terminated at any time, without obligation to pay severance or
other payments or benefits.  None of the Corporation's employees are represented
by any labor union or other organization and, there have been no attempts by or
on behalf of the Corporation's employees to be represented by a labor union.
Except as set forth in Schedule 2.1, there are no controversies pending or, to
the Corporation's best knowledge, threatened between the Corporation and its
employees or consultants, present or former.  The Corporation considers its
relations with employees to be good.  Schedule 4.34 also contains a complete and
correct list, as of the date of this Agreement, of all bonus, deferred
compensation, severance, pension, profit-sharing, retirement, insurance, stock
purchase, stock option and other fringe benefit plans, written or otherwise,
maintained or sponsored by the Corporation or any of its Affiliates in which
employees or former employees of the Business are eligible to participate.

          4.14.  Undisclosed Liabilities.  To the Corporation's best knowledge,
                 -----------------------
neither the Corporation nor the Business is liable for or subject to any
material Liabilities, except material Liabilities adequately and specifically
disclosed or reserved for in the Financial Statements or, if incurred subsequent
to the date of the Corporation's balance sheet included in the Financial
Statements, disclosed and adequately reserved for in the Books and Records.

                                       6
<PAGE>

          4.15.  Books of Account; Returns and Reports; Taxes.  The Corporation
                 --------------------------------------------
has paid in full all Taxes which were due and payable to date, and the Books and
Records reflect appropriate accruals and reserves for Taxes in respect of
current periods which are not yet due and payable. The Corporation has duly and
timely filed all Tax returns required to have been filed to date in all
applicable jurisdictions with respect to the Business or otherwise. The
Corporation has made all deposits required with respect to withholding Taxes for
employees of the Business.

          4.16.  Transactions With Affiliates.  Except as set forth in Schedule
                 ----------------------------
4.16, the Corporation has no outstanding contract, agreement or other
arrangement with an Affiliate of the Corporation with respect to the Business,
and none of the Corporation's assets is owned by or leased, licensed or
otherwise used by the Corporation under grant from any of such Affiliate.

          4.17.  Broker's or Finder's Fees.  No broker, finder or other Person
                 -------------------------
acting in a similar capacity has acted directly or indirectly for the
Corporation in connection with this Agreement or the transactions contemplated
by this Agreement.

          4.18.  No Misleading Statements.  This Agreement and all documents
                 ------------------------
furnished or to be furnished by the Corporation to the Investor referenced in
this Agreement do not and will not contain any untrue statement of material fact
or omit to state any material fact necessary to make the statements made and to
be made not misleading in any material respect.

     5.  REPRESENTATIONS AND WARRANTIES OF THE SERIES C INVESTORS.  Each of the
         --------------------------------------------------------
Series C Investors makes the following representations and warranties to the
Corporation, severally and not jointly, and each with respect only to itself or
himself:

          5.1.   Organization and Authority.  Such Series C Investor, if not a
                 --------------------------
natural person, is duly organized, validly existing and in good standing under
the laws of its jurisdiction of formation.  Such Series C Investor has full
power and authority to enter into this Agreement and to perform its or his
obligations under this Agreement.  The signing, delivery and performance of this
Agreement and the Shareholders Agreement by such Series C Investor have been
duly authorized by all necessary action on the part of such Series C Investor,
and no further action is required on such Series C Investor's part in order to
authorize this Agreement and the Shareholders Agreement or the transactions
contemplated by this Agreement and the Shareholders Agreement.  This Agreement
and the Shareholders Agreement are the legal, valid and binding obligations of
such Series C Investor, duly enforceable against such Series C Investor in
accordance with their terms.

          5.2.   No Conflict or Violation.  Neither the signing and delivery of
                 ------------------------
this Agreement or the Shareholders Agreement by such Series C Investor nor the
performance by such Series C Investor of the transactions contemplated by this
Agreement or the Shareholders Agreement will result in (i) a violation of or
conflict with the governing documents of such Series C Investor, if not a
natural person; (ii) a violation of any Laws or any Order to which such Series C
Investor is subject; or (iii) a breach or default under any mortgage, indenture,
deed of

                                       7
<PAGE>

trust, real property or personal property lease, license, contract or other
agreement to which such Series C Investor is subject.

          5.3.  Consent and Approvals.  The signing, delivery and performance by
                ---------------------
such Series C Investor of this Agreement and the transactions contemplated by
this Agreement do not require the consent, approval or authorization of, or any
declaration, filing, registration or notice with or to any governmental or
regulatory authority, or any other Person.

          5.4.  Purchase of Investment.  Such Series C Investor is an Accredited
                ----------------------
Investor as defined under Rule 5.01(a) of the Securities Act of 1933, as
amended.  Such Series C Investor is purchasing the Series C Shares pursuant to
this Agreement for its or his own account and not with a view to the
distribution thereof.

          5.5.  Broker's or Finder's Fees.  No broker, finder or other Person
                -------------------------
acting in a similar capacity has acted directly or indirectly for such Series C
Investor in connection with this Agreement and the transactions contemplated by
this Agreement.

     6.  OTHER COVENANTS.
         ---------------

          6.1.  The Corporation shall keep in full force and effect, and shall
pay all premiums on, a term life insurance policy on the life of Joseph Beninati
in the amount of $5,000,000 as to which the Corporation shall be the owner and
the beneficiary..

          6.2.  The Corporation shall furnish the following financial statements
to the Series C Investors:

                6.2.1.  as soon as practicable and in any event within 90 days
after the end of each fiscal year of the Corporation, the balance sheet of the
Corporation as at the end of such fiscal year and the related statements of
income, retained earnings and changes in financial position for such fiscal
year, setting forth in each case in comparative form (for each year other than
the first fiscal year) corresponding figures from the preceding annual audit,
prepared in accordance with generally accepted accounting principles
consistently applied and certified by independent public accountants selected by
the Corporation and reasonably satisfactory to the Series C Investors; and

                6.2.2.  as soon as practicable and in any event within 45 days
after the end of each of the first three quarters in each fiscal year of the
Corporation, the balance sheet of the Corporation as at the end of such
quarterly period and the related statements of income, retained earnings and
changes in the financial position for such quarterly period and for the elapsed
portion of the fiscal year ended with the last day of such quarterly period, and
in each case setting forth comparative figures for the related periods in the
prior fiscal year, all of which shall be prepared in accordance with generally
accepted accounting principles, consistently applied, subject to normal year-end
audit adjustments.

     7.  CLOSING DELIVERIES.
         ------------------

                                       8
<PAGE>

          7.1  Closing.  The closing of the transactions contemplated by this
               -------
Agreement (the "Closing") shall take place concurrently with the signing and
delivery of this Agreement.

          7.2  The Corporation's Closing Deliveries.  Concurrently with this
               ------------------------------------
Agreement, the Corporation is delivering the following items:

               7.2.1.  A certificate dated as of the date of this Agreement, of
the secretary of the Corporation certifying as to (i) the certificate of
incorporation and bylaws of the Corporation; and (ii) resolutions of the Board
of Directors and the shareholders of the Corporation authorizing the execution,
delivery and performance of this Agreement, all documents contemplated by this
Agreement and the transactions contemplated by this Agreement.

               7.2.2.  Certificates of "good standing" of the Corporation from
the Secretaries of State of Delaware, Connecticut and New York.

               7.2.3.  Consent of Directors, among other things, authorizing (a)
the amendment and restatement of the Corporation's Certificate of Incorporation,
as previously amended, to increase the authorized number of shares of
Convertible Preferred Stock of the Corporation by 6,666,666 shares to 16,666,666
shares, and to designate such 6,666,666 new shares as Series C Shares; and (b)
the transactions contemplated by this Agreement.

               7.2.4.  Stock certificates issued to the Series C Investors for
the number of Series C Shares set forth on Schedule 2.1.

               7.2.5.  The Shareholders Agreement signed by the Corporation and
the Preferred Shareholders other than the Series C Investors.

          7.3.  Closing Deliveries of the Series C Investors.  At the Closing,
                --------------------------------------------
each Series C Investor shall deliver or cause to be delivered the following
items to the Corporation:

               7.3.1.  The sum set forth opposite its or his name in Schedule
2.1, by wire transfer for the purchase price of the Series C Shares to be
purchased pursuant to this Agreement.

               7.3.2.  The Shareholders Agreement signed by such Series C
Investor.

     8.  SURVIVAL OF REPRESENTATIONS, WARRANTIES AND COVENANTS.  All covenants,
         -----------------------------------------------------
representations and warranties in this Agreement or in any documents delivered
pursuant to this Agreement shall survive the Closing.

     9.  INDEMNIFICATION.
         ---------------

          9.1.  Indemnification by the Corporation to the Series C Investors.
                ------------------------------------------------------------
The Corporation shall indemnify, defend and hold each of the Series C Investors,
the Affiliates of each Series C Investor, and their respective, shareholders,
officers, directors, employees, assignees and successors, harmless against, and
shall reimburse each of the indemnified Persons

                                       9
<PAGE>

on demand on account of, any Losses which may be asserted against, imposed on or
incurred by any of them as a result of or arising out of or in any manner
relating or attributable to any inaccuracy in or breach of the representations,
warranties or covenants on the part of the Corporation in this Agreement or in
any document delivered by the Corporation pursuant to this Agreement.

          9.2.  Indemnification by the Series C Investors to the Corporation.
                ------------------------------------------------------------
Each Series C Investor, severally and not jointly, shall indemnify, defend and
hold the Corporation and the Corporation's officers, directors, employees,
assignees and successors, harmless against, and shall reimburse each of the
indemnified Persons on demand on account of, any Losses which may be asserted
against, imposed on or incurred by any of them as a result of or arising out of
or in any manner relating or attributable to any inaccuracy in or breach of such
Series C Investor's representations or warranties in this Agreement or in any
document delivered by such Series C Investor pursuant to this Agreement.

     10.  MISCELLANEOUS.
          -------------

          10.1.  Notices.  Notices given pursuant to this Agreement must be in
                 -------
writing.  They shall be deemed to have been duly given:  (i) upon delivery or
refusal to accept delivery, if hand-delivered; (ii) when transmitted, if sent by
fax with confirmed receipt, followed by a "hard" copy delivered by any other
method specified in this Section 12.1; or (iii) one (1) business day after being
deposited for next-day delivery with Federal Express or other national overnight
courier service.  In each case, notice shall be addressed to the parties as
follows:

          If to the Corporation:
          ---------------------

            Greenwich Technology Partners, Inc.
            200 Railroad Avenue
            Greenwich, Connecticut 06830
            Attention:  Joseph Beninati
            Fax:  (203) 661-4554

                                       10
<PAGE>

          If to the Investor:
          ------------------

            Davis Capital LLC
            2015 West Main Street
            Stamford, Connecticut 06902
            Attention:  Ronald V. Davis

                         and

            FG-GTPC
            72 Cummings Point Road
            Stamford, Connecticut 06902
            Attention:  Kathleen Sheppird

            With a copy to:

            Orloff, Lowenbach, Stifelman & Siegel, P.A.
            101 Eisenhower Parkway
            Roseland, New Jersey 07068
            Attention:  Stanley Schwartz, Esq.
            Fax:  (973) 622-3073

          If to the Other Investors:
          -------------------------

            As set forth on the signature page hereof

or to such other place and with such other concurrent copies as the parties may
subsequently designate by written notice.

          10.2.  Amendment; Waiver.  None of the provisions of this Agreement
                 -----------------
may be changed, modified, waived or cancelled orally or otherwise except in
writing, signed by the party against whom the change, modification, waiver or
cancellation is sought to be enforced.

          10.3.  Binding Effect; Assignment.  This Agreement is binding on the
                 --------------------------
Corporation, the Series C Investors and their respective successors in interest.
No party may assign his or its rights and obligations under this Agreement
without the prior written consent of the other parties.  There are no third-
party beneficiaries of this Agreement, and any intention to afford any right or
benefit under this Agreement to any third party is specifically disclaimed.

          10.4.  Entire Agreement.  This Agreement and the Shareholders
                 ----------------
Agreement embody the entire understanding among parties with respect to the
subject matter of this Agreement.  There are no binding agreements or
understandings among the parties with respect to the transactions contemplated
by this Agreement other than as expressly set forth in this Agreement or the
Shareholders Agreement.

                                       11
<PAGE>

          10.5. Interpretation; Construction.
                ----------------------------

                10.5.1.  The terms of this Agreement have been fully negotiated
by the parties in consultation with counsel, and the wording of this Agreement
has been arrived at by all of them as a result of their joint discussions.
Accordingly, no provision of this Agreement shall be construed against a
particular party or in favor of another party merely because of which party (or
its representative) drafted or supplied the wording for such provision.

                10.5.2.  Except where otherwise noted in context, all references
to "Sections", "Exhibits" or "Schedules" shall be deemed to refer to the
sections or subsections, as appropriate, exhibits or schedules of this
Agreement.

                10.5.3.  Section headings appearing in this Agreement are
inserted solely as reference aids for the ease and convenience of the reader;
they shall not be deemed to modify, limit or define the scope or substance of
the provisions they introduce, nor shall they be used in construing the intent
or effect of such provisions.

                10.5.4.  Where the context requires:  (i) use of the singular or
plural incorporates the other, and (ii) pronouns and modifiers in the masculine,
feminine or neuter gender shall be deemed to refer to or include the other
genders.

                10.5.5.  As used in this Agreement, the terms "include[s]" and
"including" mean "including but not limited to"; that is, in each case the
example or enumeration which follows the use of either term is illustrative but
not exclusive or exhaustive.

          10.6. Expenses.  The Corporation shall pay at the Closing (or
                --------
reimburse such Series C Investor for, as the case may be) the fees and
disbursements of counsel to FG-FTPC for services rendered and expenses incurred
in connection with the negotiation and consummation of the transactions
contemplated by this Agreement.

          10.7. Prevailing Party.  In any Proceeding to enforce any provision
                ----------------
of this Agreement, the substantially prevailing party shall be entitled to
recover reasonable attorneys' fees and out-of-pocket expenses from the other
party, as determined by a court having jurisdiction.

          10.8. Multiple Counterparts.  This Agreement may be signed in one or
                ---------------------
more counterparts, all of which shall be considered one and the same agreement
and shall become effective when each of the parties has signed and delivered a
counterpart to the other.

          10.9. Further Assurances.  The parties agree, upon request and for no
                ------------------
additional consideration, to sign, acknowledge and deliver any documents and to
do anything else which the other may reasonably request in order to carry out
more completely the purpose and intent of this Agreement consistent with its
terms.

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<PAGE>

          10.10  Governing Law.  This Agreement shall be governed by and
                 -------------
interpreted according to the Laws of Delaware, but without giving effect to any
Delaware choice of law provisions which might otherwise make the Laws of a
different jurisdiction govern or apply.

                            [Signature Page follows]

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<PAGE>

                              Greenwich Technology Partners, Inc.



                              By:   /s/ Joseph Beninati
                                    ----------------------------------------
                                    Joseph Beninati, Chief Executive Officer


                              FG-GTPC


                              By:   /s/ Joseph Beninati
                                    ----------------------------------------
                                    Joseph Beninati, Chief Executive Officer



                              Other Investors:

                              Name:  Russell J. Carpentieri Retirement Plan
                                    ----------------------------------------

                                        By:  /s/ Russell J. Carpentieri
                                             -------------------------------
                                        Print Name and Title:

                                        ____________________________________

                                        ____________________________________

                                        Print Address for Notice:

                                        1025 West Chester Avenue
                                        ------------------------------------

                                        White Plains, NY 10604
                                        ------------------------------------

                                        914-288-8950 (PHONE)
                                        ------------------------------------

                                        914-288-8803 (FAX)
                                        ------------------------------------

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