<PAGE>

                                                                   EXHIBIT 10.13


   CONFIDENTIAL MATERIALS OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
                EXCHANGE COMMISSION. ASTERISKS DENOTE OMISSIONS.


                                      CORECHANGE PROFESSIONAL SERVICES AGREEMENT

[LOGO]

260 Franklin Street
Suite 1890
Boston, MA  02110
617-204-3300
617-204-3333 (fax)


<TABLE>

<S>               <C>
|X| CLIENT
    INFORMATION:  ABN AMRO INFORMATION TECHNOLOGY SERVICES CO.
                  ---------------------------------------------        -----------------------------------
                  Client Name                                          Billing Organization

                  200 West Monroe Drive
                  ---------------------------------------------        -----------------------------------
                  Installation Address                                 Billing Address

                  Chicago IL 60606
                  ---------------------------------------------        -----------------------------------
                  City, State, Zip                                     City, State, Zip

                  Jesse Andrews   312 904 1821
                  ---------------------------------------------        -----------------------------------
                  Contact Name and Telephone                           Attention

</TABLE>

|X| SERVICES:

|X| ESTIMATED SERVICES AND TRAINING:  [**] (50 PERSON-DAYS)

|X| SERVICE RATE:  [**] PER 8 HOUR PERSON-DAY

|X| PROFESSIONAL SERVICES:  TERMS AND CONDITIONS WITH ATTACHMENT

By signing below, each party agrees to be bound by the terms of this
Professional Services Agreement ("Agreement"). It is understood that each party
may consider any fully signed reproduction of this Agreement to be a binding
original, if the reproduction is made by reliable commercial means (e.g.
photocopy, facsimile, e-mail). This Agreement represents the entire
understanding between the parties and supersedes all prior oral agreements,
writings and understandings. The Agreement shall not be binding upon Corechange
until reviewed and signed by the President or Vice President of Finance and
Administration at its Boston, Massachusetts headquarters. This Agreement shall
have an "Effective Date" on the last day signed below.

Corechange, Inc.                    ABN AMRO Information Technology Services Co.

/s/ Ulf Arnetz                      /s/ Louis F. Rosenthal
---------------------------------   --------------------------------------------
Ulf Arnetz, President/CEO           Louis F. Rosenthal
---------------------------------   --------------------------------------------
Date:  5/11/2000                    Date:  5/11/2000
---------------------------------   --------------------------------------------


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<PAGE>

                                      CORECHANGE PROFESSIONAL SERVICES AGREEMENT

                   PROFESSIONAL SERVICES: TERMS AND CONDITIONS

1. SERVICES

1.1 Corechange, its employees, agents and/or contractors shall provide the
services set out in Attachment A ("Services") on a time and materials basis.
Corechange agrees to perform the Services with care, skill and diligence and in
accordance with the applicable professional standards currently recognized by
its profession. Client agrees to fully cooperate with Corechange and provide all
assistance reasonable necessary for Corechange to provide the Services.
Corechange may experience delays resulting from Client's failure to provide the
assistance including, without limitation, the proper desktop and application
operating environments and personnel.

1.2 Corechange will replace any of its providers of services hereunder on
reasonable written request by Client, provided Client does not request removal
for an improper purpose (e.g., improper discriminatory removal). When on
Client's premises, Corechange will comply with reasonable standard workplace
rules, including rules relating to security and safety, provided in writing and
in advance to Corechange by Client.

2. LICENSE

Corechange grants Client a non-exclusive, non-transferable, perpetual license to
use any software developed as a result of the Services ("Deliverables") but only
with the Licensed Materials and subject to the conditions thereof set out in the
License Agreement between the parties executed on an even day herewith.

3. TERM AND TERMINATION

This Agreement shall commence on the Effective Date and shall continue until the
services are completed. Either party may terminate this Agreement upon ten (10)
days prior written notice. Termination shall not extinguish any amount owed that
accrued prior to termination.

4. FEES, EXPENSES AND PAYMENT

Client shall pay Corechange fees at the rate indicated on the Cover Page of this
Agreement. The number of days and total cost are good faith estimates only. The
total cost to Client may be more or less than the estimate. Client shall also
reimburse Corechange for reasonable travel and other expenses incurred as a
result of this Agreement. In addition to the fees set forth in this Section,
Client shall pay or reimburse Corechange for all federal, state, local or other
taxes (exclusive of income, business privilege, or similar taxes), including but
not limited to, sales, use, lease or similar assessments, based on charges for
the Deliverables rendered hereunder. In the event Client cancels or unilaterally
reschedules the commencement date for the Services within seven (7) calendar
days prior to the agreed upon commencement date, Client shall be liable to pay
Corechange any actual damages and non-cancelable expenses resulting from such
cancellation or rescheduling. Within thirty (30) days of termination or
expiration of this Agreement for any reason, Corechange shall submit to Client
an itemized, final invoice for any fees or expenses accrued under this
Agreement. Corechange may invoice periodically during performance of the
Services. Client agrees to pay all amounts on invoices not subject to a good
faith dispute within thirty (30) days of receipt. In case of a good faith
dispute, Client will notify Corechange in writing within 15 days, pay all
undisputed amounts, and work diligently with Corechange to resolve the dispute.
Invoices remaining unpaid for a period of sixty (60) days following the date the
invoice was sent shall accrue interest at a rate of one percent per month or at
the maximum rate permitted by law whichever is less on any unpaid amount.

5. RIGHTS IN DELIVERABLES

Corechange shall hold all rights, title and interest, including but not limited
to patents, letter patent, patent applications, copyrights and/or trade secrets,
in and to the Deliverables, except to the extent the Deliverables incorporate
any Proprietary Information of Client's. All Deliverables are subject to
copyright protection under applicable United States laws and statutes. Client
will not remove from the Deliverables any of Corechange's copyright or other
proprietary rights notices. Corechange does not waive any moral rights,
including any right to identification of authorship, rights of approval on
modifications or limitation on subsequent modification, Corechange has or may
have in any Deliverables.

6. WARRANTY

6.1 Corechange hereby represents and warrants that it has sufficient right,
title, and interest necessary to perform the Services. Corechange will not
introduce any virus or intentionally disabling code into the Deliverables;
Client's exclusive remedy shall be for Corechange to repair or replace the
Deliverables to remove any such viruses or disabling code at no additional
charge.

6.2 EXCEPT AS EXPRESSLY PROVIDED IN THIS AGREEMENT, CORECHANGE PROVIDES THE
DELIVERABLES "AS IS" AND MAKES NO WARRANTIES OF ANY KIND, EITHER EXPRESSED OR
IMPLIED, INCLUDING, BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND
PERFORMANCE OF THE DELIVERABLES AND SERVICES IS WITH CLIENT.


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<PAGE>

                                      CORECHANGE PROFESSIONAL SERVICES AGREEMENT

7. PROPRIETARY INFORMATION

Both Corechange and Client may make available to the other confidential and
proprietary materials and information ("Proprietary Information"). All material
and information provided by one party to the other relating to its business,
policies, procedures, customs, forms, customers and strategies, and identified
in writing as "confidential" or "proprietary" or is such that a reasonable
person should know would be considered confidential, shall be considered to be
Proprietary Information. The pricing terms of this Agreement and the
Deliverables shall be deemed Proprietary Information of Corechange, whether or
not identified in writing as such. Proprietary Information does not include
information that: (i) is already, or otherwise becomes, generally known by third
parties as a result of no act or omission of the receiving party; (ii)
subsequent to disclosure hereunder is lawfully received from a third party
having the right to disseminate the information without restriction on
disclosure; (iii) is generally furnished to others by the disclosing party
without restriction on disclosure; (iv) was already known by the receiving party
prior to receiving them from the disclosing party and were not received from a
third party in breach of that third party's obligations of confidentiality; or
(v) is independently developed by the receiving party without the use of
Proprietary Information of the disclosing party. Each party shall maintain the
confidentiality of the other party's Proprietary Information and will not use or
disclose such Proprietary Information without the written consent of the other
party. Notwithstanding the foregoing, a party may disclose the Proprietary
Information of the other to its agents and other third parties on a need-to-know
basis, provided that such parties are under a similar obligation to maintain the
confidentiality of the Proprietary Information. Further, the parties may
disclose the other's Proprietary Information in a judicial or quasi-judicial
proceeding when required to do so by law when responding to a subpoena,
deposition notice or similar judicial or governmental demand; in such
situations, however, the party being requested to disclose the other's
Proprietary Information shall endeavor to provide notice to the other party
whereby the other party may intervene in the proceeding, if it wishes, and
endeavor to prevent such disclosure. Additionally, the parties may disclose the
other's Proprietary Information to their various regulatory agencies if
required, provided they take reasonable steps to limit further disclosure.
Notwithstanding any contrary provision of this Agreement, as long as each party
protects the Proprietary Information of the other, neither the exposure to the
other party's Proprietary Information, nor its ownership of work products, shall
prevent either party from using ideas, concepts, expressions, know-how, skills
and experience possessed by either party prior to its association with the other
party or developed by either party during its association with the other party,
so long as the Proprietary Information of the other party is not used. In case
of breach, the disclosing party shall have the right to seek injunctive relief.

8. ASSIGNMENT

The rights granted to Client under this Agreement are restricted exclusively to
Client and may not be assigned, subleased, sublicensed, sold or otherwise
transferred. Any assignment of this Agreement or any claim arising under this
Agreement by Client without Corechange's prior written consent shall be void.
Corechange may not assign its obligations hereunder without prior written
consent of Client. Corechange may use third parties to perform Services
hereunder, provided that Corechange shall be responsible to Client for the
Services performed by such third parties.

9. INDEMNIFICATION

If a claim or action is brought against Client by a third party arising from a
claim that the Deliverables or Client's use or possession thereof infringes a
patent, copyright, trade secret, or other intellectual property right of a third
party, Corechange shall defend such claim or action at its expense and shall pay
all costs, attorney's fees, damages, settlements and other amounts awarded or
agreed to in connection with any such claim or action, provided that Client
provides (x) prompt written notice of the claim, (y) all reasonable assistance,
and (z) control of the claim to Corechange. Corechange shall have no obligation
to indemnify if the claim arises from (i) the use of the Deliverables with other
products not provided by Corechange; or (ii) any unauthorized uses of or
modifications to the Deliverables. If Client is enjoined, precluded, or advised
by Corechange to refrain from using the Deliverables because of any such
infringement or any infringement claim or allegation, Corechange shall, and at
Corechange's expense and option: (a) procure for Client the right to continue
using the Deliverables; or (b) replace or modify the Deliverables so that they
becomes non-infringing with minimal effect on the performance of the
Deliverables. This provision states the sole and exclusive liability of
Corechange for infringement or breach of third party rights.

10. INSURANCE. For one year after the Effective Date, Corechange agrees to
maintain comprehensive general liability and property damage insurance coverage
for bodily injuries to persons and damage to physical property with limits of at
least $1,000,000 for bodily injury to persons and $1,000,000 for damage to
physical property.

11. GENERAL

11.1 EXCEPT FOR CORECHANGE'S OBLIGATIONS UNDER SECTION 9, CORECHANGE'S AGGREGATE
LIABILITY TO CLIENT SHALL NOT EXCEED THE AMOUNTS PAID HEREUNDER. EXCEPT FOR A
BREACH OF SECTION 7 AND CORECHANGE'S OBLIGATIONS UNDER SECTION 9, IN NO EVENT
SHALL EITHER PARTY BE LIABLE TO THE OTHER OR ANY OTHER PARTY FOR ANY INCIDENTAL,
INDIRECT, SPECIAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES OR LOST PROFITS ARISING
OUT OF OR RELATED TO THIS AGREEMENT.

11.2. Each party shall, at its own expense, comply with all applicable federal
and state laws, statutes and regulations relating to the performance of this
Agreement.



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<PAGE>

                                      CORECHANGE PROFESSIONAL SERVICES AGREEMENT

11.3 Nothing contained herein will in any way constitute a party or that party's
employees, agents, or servants to be employees, agents or servants of the other
party, and they will in no way represent themselves as agents, servants or
employees of the other party.

11.4 Neither party shall be held liable for failure to fulfill its obligations
under this Agreement, if such failure is caused by flood, extreme weather, fire,
or other natural calamity, acts of governmental agency, or similar causes beyond
the reasonable control of such party.

11.5 This written Agreement embodies the entire understanding between Corechange
and Client relating to its subject matter; it supersedes, merges and voids any
and all prior discussions, writings, and written or oral agreements between
Corechange and Client regarding such subject matter. Except as specifically
provided herein, this Agreement may only be altered, amended or modified in
writing, if signed by a duly authorized representative of the parties.

11.6 This Agreement shall be governed by and interpreted pursuant to the
substantive laws, but not the conflict of law rules, of the State of New York.

11.7 A copy of any notice of breach of the terms of the Agreement shall be
forwarded to: ABN AMRO North America, Inc., Attention: Legal Department, 135
South LaSalle Street, Chicago, IL 60674.



                                       4
<PAGE>

                                      CORECHANGE PROFESSIONAL SERVICES AGREEMENT


                                  ATTACHMENT A

This Attachment A is incorporated in its entirety as part of this Coreport
License Agreement between Corechange and Client.

SCHEDULED SERVICES / PROJECT PLAN:

-    Project Review - Establish scope, content, deliverables and expectations.
     Assess requirements, resources and rollout plan. Review of project plan and
     timeframes.

-    Software Installation - Basic configuration.

-    User information load/import.

-    Coreport organizational structuring, role layout and assistance.

-    Custom portal functions, creation and configuration.

-    Test and quality assurance.

-    Other related services, time permitting, based on client preferences.

-    Autonomy configuration (for Autonomy Knowledge Management as listed on
     page 1)


TRAINING:


Training is estimated to take 5 days, although more will be provided on
reasonable request by Client. Estimated training includes:


        -4 days of technical training for administrators

        -1 day of training trainers for Client's end users/employees

Class size shall be determined within reason by Client, and on a mutually agreed
to schedule at Client's place of business.



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