<PAGE>
                                                                   EXHIBIT 10.10

Portions of this Exhibit have been omitted pursuant to a request for
confidential treatment and such portions have been filed separately with the
Commission.

PRIVILEGED AND CONFIDENTIAL

                                                    August 28, 2002
                                                    As amended December 16, 2002
Patrick J. Mulchay

Dear Pat:

This Letter Agreement confirms our decision concerning your employment status.
As we discussed, you will retire from your employment with NiSource Corporate
Services Company. If you sign this Letter Agreement, it will constitute the
mutual agreement between you and NiSource Corporate Services Company ("the
Company" which, as used herein shall mean NiSource Inc. or any of its affiliates
or subsidiaries, including NiSource Corporate Services Company; except in
Exhibit 1, references to "NiSource" shall mean exclusively NiSource Inc.)
regarding the terms of your retirement.

      1.    Employment Status

            Unless you are discharged for cause (which would include but not be
            limited to a breach of Paragraph 12 of this Letter Agreement), you
            will continue as an active employee of the Company through January
            31, 2003, for all purposes, including participation in the 2002
            NiSource Inc. ("NiSource") bonus plan, all Company employee benefit
            plans and for purposes of vesting (a) any restricted stock in
            NiSource owned by you and (b) any NiSource stock options owned by
            you. Thereafter, you will retire from the Company with the benefits
            set forth herein provided that you execute a release at that time in
            the form attached as Exhibit 1 hereto.

      2.    Business Transition

            You will not be required to report to your Company office or perform
            your management duties after August 28, 2002 ("Separation Date")
            although you may be required to render services as requested to
            ensure a smooth business transition between August 28 and January
            31, 2003. After your Separation Date, you agree to cooperate
            whenever needed in the preparation for and/or defense of any
            litigation in which the Company is involved. If your assistance is
            required by the Company in such matters following the end of your
            consulting arrangement, you will be paid $1,000 per day and
            reimbursed for out-of-pocket expenses.
<PAGE>
      3.    Consulting Arrangement

            Between February 1, 2003 and March 31, 2004, you agree to provide
            consulting services to the Company as requested by the CEO and COO
            of the Company. You will be paid a fee of $15,000.00 per month for
            said consulting services, provided that your services are not
            terminated prior to March 31, 2004 for cause or due to death or
            disability. These services will include but not be limited to
            assistance with the establishment of an RTO, review of strategic
            options and general matters related to electric operations. You will
            provide these services as and you agreed that you will be an
            independent contractor and you will not be eligible to participate
            in the Company benefit plans except as specifically provided for in
            this Letter Agreement. During the consulting arrangement, you will
            be reimbursed for appropriately documented and approved business
            expenses and you will be provided comparable office space. In
            addition, at the termination of your consulting arrangement, you
            will receive a lump sum payment of $230,000.

      4.    Change In Control

            You acknowledge that you are not currently owed any benefits under
            your Change in Control and Termination Agreement ("CIC") dated
            September 1, 1997. Nonetheless, as additional consideration for your
            execution of this Agreement, the Company agrees that, if

            (a)   an acquisition of all the outstanding stock of NiSource (**)
                  is closed on or before March 31, 2006, or

            (b)   (**)

            then you will receive the benefits set forth in the CIC less the
            amounts paid to you as a result of the consulting agreement provided
            in Paragraph 3 of this Agreement; and provided that in lieu of any
            welfare benefits set forth by the terms of the CIC to which you may
            be entitled under the CIC and which you are not already receiving,
            you will receive a lump sum payment equal to the present value of
            such welfare benefits calculated as of the date of closing of such
            acquisition. You will not receive any payments under the CIC in the
            event all of the outstanding stock of NiSource is acquired under
            circumstances not specifically described in the previous sentence.

            In the event the CIC is triggered pursuant to this paragraph, you
            agree that Section 3(a)(2) of the CIC will be based on the 2002
            incentive bonus compensation plan and that Sections 3(a) (3), (4),
            (5) and (6) of the CIC will not apply.

      5.    Vacation

      **Text has been omitted pursuant to a request for confidential treatment
      and such text has been filed separately with the Commission.




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<PAGE>
            You are eligible to receive a lump sum payment representing
            compensation for your accrued and unused vacation as of January 31,
            2003. This payment will be subject to legally-mandated deductions
            for Social Security and federal, state and local taxes, as well as
            deductions for any contributory benefit plans in which you elect to
            continue participation. Your vacation accrual through December 31,
            2002 is 356 hours, with an additional 20 hours to be earned in
            January; bringing your total vacation accrual to 376 hours at the
            time of your retirement.

      6.    Retiree Medical Coverage

            You will be eligible to participate in the Company's Retiree Medical
            Plan as of February 1, 2003. You will continue to receive Ayco
            financial counseling and tax preparation for tax years 2003 and
            2004.

      7.    Contingent Shares

            Except as provided in Paragraph 1 hereof, all contingent stock
            awards granted under the NiSource Inc. 1994 Long Term Incentive Plan
            or the 1988 Long Term Incentive Plan that have not vested as of
            January 31, 2003 shall vest in accordance with Section 6 of the
            Contingent Stock Agreements dated January 29, 2000 and January 1,
            2001.

      8.    Long Term Incentive Program

            You will continue to be treated as an active employee of the Company
            through January 31, 2003 under the 1994 Long Term Incentive Plan,
            for the purpose of vesting of any restricted stock or nonqualified
            stock options which vest on or before January 31, 2003.

            You will receive the greater of your threshold or actual bonus
            earned under the 2002 NiSource Inc. bonus plan.

      9.    Indemnification

            You will be entitled to indemnification by the Company to the same
            extent as other former officers of the Company. You will also be
            entitled to coverage under the directors and officers liability
            insurance coverage maintained by the Company (as in effect from time
            to time) to the same extent as other former officers of the Company.

      10.   NiSource Re-Employment


                                      -3-
<PAGE>
            If you seek re-employment with any NiSource Company and are
            subsequently rehired, management reserves the right to base any
            future severance payments on your rehire date.

      11.   Return of Property

            You agree to return to the Company any and all of its property,
            including but not limited to, keys, employee identification or
            security access cards, telephones, computing equipment, and credit
            cards on or before March 31, 2004. As of March 31, 2004, you will be
            eligible to retain ownership on a tax-paid basis of the 2001 Ford
            Expedition which the Company had provided you through the period of
            your consulting arrangement.

      12.   Confidentiality

            You acknowledge that during your employment by the Company you had
            access to confidential information and confidential financial data
            of the Company or of other NiSource companies.

            You further acknowledge that during your employment you may have
            developed confidential business information for the Company, may
            have made inventions, and/or may have established relationships with
            the Company's customers and potential customers.

            In order to preserve the property, inventions, business, and
            goodwill of the Company, you agree that during and after your
            employment, all knowledge and information not known to the public
            respecting any Company inventions, designs, products, services,
            machinery, methods, systems, improvements, forecasts, strategic and
            other plans, financial data, and other confidential information,
            including customer information such as names and addresses of
            customers and potential customers, pricing information relating to
            any services performed or products sold by the Company, and all
            information relating to the special and particular business needs of
            the Company or its customers and potential customers, shall remain
            the exclusive property of the Company and shall be regarded by you
            as strictly confidential and shall not be directly or indirectly
            used or disclosed without the Company's written permission.

            Moreover, you agree that upon termination of your employment, you
            will promptly deliver to the Company all documentation and other
            materials relating to the Company's business which are in your
            possession or under your control, including customer and potential
            customer lists, product lists, and marketing material, whether in
            written or electronic data form; and you will delete, destroy or
            discard all copies of such confidential information remaining in
            your possession.

                                      -4-
<PAGE>
            You further acknowledge and agree that the Company's remedy in the
            form of monetary damages for any breach by you of any of the
            provisions of this section may be inadequate and that, in addition
            to any monetary damages for such breach, the Company shall be
            entitled to institute and maintain any appropriate proceeding or
            proceedings, including an action for specific performance and/or
            injunction.

      13.   Release of Claims

            In consideration of the payment and benefits described above, you,
            on behalf of yourself and your heirs, executors, and administrators,
            fully and finally settle, release, and waive any and all local,
            state (including but not limited to the Indiana Civil Rights Law),
            and federal civil, common law, statutory (including, but not limited
            to, the AGE DISCRIMINATION IN EMPLOYMENT ACT OF 1967, Title VII of
            the Civil Rights Act of 1964, the Americans with Disabilities Act of
            1990, the Family and Medical Leave Act of 1993, and the Employee
            Retirement Income Security Act of 1974, as those Acts are amended),
            and equitable claims against the Company and NiSource, Inc. and its
            subsidiaries and affiliated companies, and all of the stockholders,
            predecessors, successors, agents, directors, officers, employees,
            representatives, and attorneys of NiSource, and its subsidiaries and
            affiliated companies, known or unknown, occurring or arising prior
            to you signing this Letter Agreement.

            You acknowledge and agree that this release is being given only in
            exchange for consideration to which you are not otherwise entitled.

      14.   Outstanding Charges

            You hereby agree to pay the Company any outstanding amounts owed to
            the Company, and further agree that by signing this agreement you
            hereby authorize the Company to deduct any outstanding charges from
            your consulting or retirement payments.

      15.   Governing Law

            This Letter Agreement shall be construed in accordance with the laws
            of Indiana.

      16.   Severability

            In the event that one or more of the provisions contained in this
            Letter Agreement shall for any reason be held to be invalid, illegal
            or unenforceable in any respect, the Company shall have the option
            to enforce the remainder of this Letter Agreement or to cancel it.

      17.   Non-Disclosure

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<PAGE>
            You expressly agree to keep the terms of this Letter Agreement
            strictly confidential and that you will not disclose the terms of
            this Letter Agreement to anyone other than your spouse, your legal
            counsel or your tax advisor, provided that they each agree to
            preserve the confidentiality of the terms of this Letter Agreement.
            You agree not to disparage or portray the Company in a negative
            light. Any breach of this paragraph will be considered a material
            breach of the Letter Agreement.

            Nothing herein should be construed as a limitation on your ability
            to consult with your counsel concerning your rights but you agree
            that you will not assist or encourage others to bring claims against
            the Company.

      18.   Complete Agreement

            You acknowledge that in accepting this Letter Agreement, you have
            not relied upon any representation or promise other than those
            expressly stated in this Letter Agreement.

            This Letter Agreement constitutes the complete understanding between
            you and the Company relating to your separation and supersedes any
            and all prior agreements, promises, representations or inducements,
            no matter their form, concerning you employment with the Company. No
            promises or agreements made subsequent to the execution of this
            Agreement by these parties shall be binding unless reduced writing
            and signed by authorized representatives of these parties.

      19.   Important Information

            YOU ACKNOWLEDGE THAT THE COMPANY HAS ADVISED YOU TAKE UP TO 45 DAYS
            TO CONSIDER THE TERMS AND CONDITIONS OUTLINED ABOVE, AND THAT THE
            COMPANY HAS ALSO ADVISED YOU TO CONSULT AN ATTORNEY BEFORE SIGNING
            THIS LETTER AGREEMENT. YOU ALSO HAVE THE RIGHT TO REVOKE YOUR
            EXECUTION OF THIS LETTER AGREEMENT WITHIN 7 DAYS AFTER EXECUTION IN
            ACCORDANCE WITH THE NOTICE TO EMPLOYEE ATTACHED HERETO.

            ATTACHED TO THIS LETTER AGREEMENT AS EXHIBIT 2 ARE THE DATA
            REGARDING THOSE EMPLOYEES SELECTED AND NOT SELECTED FOR THIS
            PROGRAM. THE DATA INCLUDE A DESCRIPTION OF THE UNITS, JOB TITLES AND
            AGES OF ALL EMPLOYEES SELECTED FOR THE PROGRAM, AND THE AGES AND JOB
            TITLES OF EMPLOYEES IN THE AFFECTED UNITS NOT SELECTED FOR THE
            PROGRAM.

            IF YOU ACCEPT THE TERMS AND CONDITIONS OUTLINED ABOVE, INCLUDING
            PARAGRAPH 13, PLEASE SIGN BOTH COPIES OF THIS LETTER AGREEMENT IN
            THE SPACE PROVIDED BELOW TO SIGNIFY YOUR ACCEPTANCE, AND RETURN BOTH
            COPIES TO LANETTE ZIMMERMAN BY DECEMBER 18, 2002, ON WHICH DATE THIS
            OFFER WILL EXPIRE IF NOT




                                      -6-
<PAGE>
            ACCEPTED. IF YOU ACCEPT THE TERMS AND CONDITIONS OUTLINED ABOVE,
            YOUR ACCEPTANCE IS IN LIEU OF ANY AND ALL OTHER SEVERANCE PROGRAMS
            OFFERED BY THE COMPANY AND YOU KNOWINGLY AND VOLUNTARILY WAIVE
            PARTICIPATION IN ALL OTHER SEVERANCE PROGRAMS OFFERED BY THE
            COMPANY. YOU ACKNOWLEDGE THAT THE COMPANY'S PERFORMANCE UNDER THIS
            AGREEMENT CONSTITUTES FULL AND COMPLETE PAYMENT OF ALL AMOUNTS DUE
            TO YOU FROM THE COMPANY AND CONSTITUTES ADDITIONAL CONSIDERATION TO
            WHICH YOU ARE NOT OTHERWISE ENTITLED.

                                                    Very truly yours,

                                                    /s/ Gary L. Neale
                                                    Gary L. Neale

         Accepted:

         /s/ Patrick J. Mulchay                     Date:    12/22/02
         ---------------------------                ---------------------
         Patrick J. Mulchay

         Witness:
         /s/ Denisa R.L. Margraf                    Date:    12/22/02
         ------------------------                   ----------------------




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