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                                                                  EXHIBIT 10(nn)

                            FOURTH AMENDMENT TO LEASE

          THIS FOURTH AMENDMENT TO LEASE AGREEMENT (this "Agreement") dated as
of December 28, 2000, by and between RANDOLPH/CLINTON LIMITED PARTNERSHIP, a
Delaware limited partnership ("Landlord"), with an address at c/o W.P. Carey &
Co. LLC, 50 Rockefeller Plaza, 2nd Floor, New York, NY 10020, and INFORMATION
RESOURCES, INC., a Delaware corporation ("Tenant") with an address at 150 North
Clinton Street and 564 West Randolph Street, Chicago, ILL.


                                   WITNESSETH:
                                   -----------
          WHEREAS, Landlord and Tenant entered into a certain Lease Agreement
dated of September 27, 1990, as amended by that certain Amendment Number 1 to
Lease Agreement between Landlord and Tenant dated as of March 29, 1991, as
further amended by that certain Second Amendment to Lease Agreement dated as of
March 29, 1995 between Landlord and Tenant, as further amended by that certain
Waiver, Consent and Covenant Agreement dated as of February 8, 1999 between
Landlord and Tenant, as further amended by that certain Third Amendment and
Waiver Agreement dated as of February 9, 2000 between Landlord and Tenant (as so
amended, the "Lease");

          WHEREAS, Landlord and Tenant desire to amend the Lease in the manner
set forth hereinafter;

          NOW, THEREFORE, intending to be legally bound, the parties hereto
agree as follows:

1.   Capitalized terms used herein and not defined herein shall have the
     meanings assigned to such terms in the Lease, as amended hereby.

2.   The covenants set forth in paragraph C(iv) of Exhibit E to the Lease are
     hereby deleted. The definition of Consolidated Operating Income set forth
     on Exhibit E to the Lease is amended so as to exclude from Consolidated
     Operating Income (but only for the fiscal years ending December 31, 2001
     and December 31, 2002) non-recurring, non-cash asset impairment charges
     which would otherwise have been included in Consolidated Operating Income
     for such periods in accordance with Exhibit E to the Lease. The amendments
     to the Lease set forth in this paragraph 2 shall be effective only upon
     delivery to Landlord of the initial Letter of Credit (as defined
     hereinafter) within the time periods specific in paragraph 3 of this
     Agreement.

3.   As additional security for (i) the payment of Rent, (ii) the performance by
     Tenant of its obligations under paragraphs 10 and 12 of the Lease, and
     (iii) performance by Tenant of its other monetary obligations under the
     Lease (as amended hereby) (the obligations in clauses (i), (ii) and (iii)
     being referred to herein as the "Obligations"), Tenant shall provide to
     Landlord, within 10 business days following execution of this Agreement by
     Tenant, a standby letter of credit naming Landlord as the beneficiary in
     the amount of $2,465,652. Such letter of credit, and any substitute
     therefor provided to Landlord in the manner set forth hereinafter and
     meeting the conditions specified herein, is referred to herein as the
     "Letter of Credit". The Letter of Credit shall be in form and scope
     reasonably satisfactory to Landlord and (a) shall be irrevocable and
     unconditional, (b) must be issued by Harris Trust and Savings Bank or
     another financial institution having a rating on its long term unsecured
     senior debt of AA- or better from Standard & Poors Corporation or Aa3 or
     better from Moody's Investor Services, Inc. (and if the rating of the long
     term unsecured senior debt of either Harris Trust and Savings bank or any
     other issuer of the Letter of Credit does not at any time meet the minimum
     ratings specified in this clause (b), Tenant shall provide Landlord with a
     replacement Letter of Credit within 30 days following written notice to
     Tenant), (c) shall have a term of at least one year, (d) shall state that
     it may be drawn in whole or in part by a draft at sight in the amount of
     such drawing, accompanied only by a letter addressed to the issuing bank
     and signed by the then beneficiary of the Letter of Credit stating as
     follows: "An event has occurred which entitles the beneficiary of letter of
     credit number ____ dated ______ issued by ______ to make a drawing on such
     letter of credit.", (e) shall state that it may be assigned one or more
     times by the Landlord to (x) any Lender (including The Chase Manhattan
     Bank, its successors and assigns) or (y) any buyer of any of the Leased
     Premises, and shall also state that it may be assigned one or more times by
     Lender to any assignee of Lender, in all cases without payment of any fee
     to the issuing bank, (f) shall state that it shall be automatically renewed
     for a successive one year term unless the issuing bank notifies the
     beneficiary thereof in writing (by registered mail, return receipt
     requested) at least 45 days prior to the expiration date of the Letter of
     Credit then held by beneficiary that such Letter of Credit will not be so
     renewed. Tenant shall keep such Letter of Credit in effect during any
     period Tenant does not have a rating on its long term unsecured senior debt
     (or, if the Tenant does not have any outstanding long term unsecured senior
     debt, Tenant does not have a shadow rating) of at least BBB or better from
     Standard & Poors Corporation or a successor thereto or at least Baa2 or


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     better from Moody's Investor Services, Inc. or a successor thereto, it
     being understood that Tenant need not keep such Letter of Credit in effect
     with Landlord during any period in which the rating on Tenant's senior
     unsecured debt (or, if Tenant does not have any outstanding long term
     unsecured senior debt, Tenant's shadow rating, if any) meets or exceeds the
     foregoing specified minimum ratings.

4.   The Letter of Credit shall be held by Landlord (or its assignee) as
     additional collateral for the payment and/or performance of the
     Obligations. Upon occurrence of any Draw Default (as defined hereinafter)
     specified in clause (c) of paragraph 6(i) of this Agreement, the Landlord
     (or its assignee) shall be entitled to draw the Letter of Credit to the
     extent necessary to cure such Draw Default, but the Landlord shall not be
     obligated to do so. Accordingly, if such a Draw Default occurs which also
     constitutes an Event of Default, the Landlord may exercise all of its
     rights and remedies under the Lease as amended hereby and the Letter of
     Credit shall continue to be held as additional collateral for payment
     and/or performance of the Obligations.

5.   Upon occurrence of any Draw Default specified in clauses (a) or (b) of
     paragraph 6(i) of this Agreement, then Landlord (or its assignee) may draw
     the Letter of Credit in full. If the then beneficiary of the Letter of
     Credit is a Lender, then such sums may be deposited by Lender into a
     general account of Lender and may be commingled with other funds of Lender
     and no interest need be paid to Landlord or Tenant. If the then beneficiary
     is the Landlord and Landlord is permitted by Lender to hold such funds,
     such funds shall not be commingled with other funds of the Landlord but
     shall be deposited into a separate interest-bearing account of Landlord
     with interest earned (a) to be taxed to Tenant and (b) to be held in such
     account as part of the funds drawn under the Letter of Credit. In such
     event, the funds so held may be used to cure a Draw Default specified in
     clause (c) of paragraph 6 (i) of this Agreement (although the Landlord
     shall not be obligated to use funds to do so and the Landlord may exercise
     all of its other rights and remedies against the Tenant if an Event of
     Default has occurred and is continuing) or such funds shall be held by
     Landlord (or its assignee) as additional collateral for the payment and/or
     performance of the Obligations.

6.   (i) As used herein, "Draw Default" shall mean any one or more of the
     following events: (a) the Letter of Credit then held by the Landlord (or
     its assignee) is not renewed or extended for an additional term of at least
     one year, or is not replaced with a replacement Letter of Credit, on or
     prior to a date which is 30 days prior to the expiration date of the Letter
     of Credit then held by the Landlord or its assignee, or the Letter of
     Credit then held by Landlord (or its assignee) is not replaced within the
     time period specified in paragraph 3(b) of this Agreement (in the event of
     a downgrade of the issuing bank's credit as specified in paragraph 3(b) of
     this Agreement), (b) if a partial drawing is made on the Letter of Credit,
     Landlord (or its assignee) does not receive from the issuing bank, within
     30 days thereafter, a notice reinstating the amount which may be drawn
     under the Letter of Credit to $2,465,652, or (c) an Event of Default (as
     defined in the Lease, as amended hereby) occurs due to the Tenant's failure
     to timely pay or perform any Obligation.

          (ii) An additional Event of Default (as defined in the Lease) shall
occur if (a) the Letter of Credit then held by Landlord (or its assignee)
expires or terminates without being drawn in full and is not replaced by Tenant
with a replacement Letter of Credit within 30 days following written notice to
Tenant, or (b) Tenant fails to deliver the initial Letter of Credit to Landlord
within the time period specified in paragraph 3 of this Agreement and such
failure continues for 5 days following written notice from Landlord to Tenant.

          (iii) Within 15 days following any draw on the Letter of Credit,
Landlord shall give Tenant written notice of such draw.

7.   So long as no Draw Default specified in clause (c) of paragraph 6(i) has
     occurred and is continuing, the Letter of Credit (or, if the Letter of
     Credit was previously drawn and cash is being held pursuant to paragraph 5
     of this Agreement, then the amount of cash then so held pursuant to
     paragraph 5) shall be returned to Tenant upon the earlier to occur of the
     date on which Tenant meets or exceeds the minimum credit ratings specified
     in paragraph 3 of this Agreement (subject to Tenant's obligation to provide
     a new Letter of Credit if Tenant's credit ratings subsequently fall below
     those minimum ratings specified in paragraph 3 of this Agreement) or the
     expiration or earlier termination of the Lease Term and, in the event of
     such expiration or earlier termination, only after payment and performance
     by Tenant of all Obligations.

8.   Tenant shall, from time to time upon request of Landlord, provide to
     Landlord copies of documents evidencing Tenant's then existing credit
     facilities and amendments thereto.

9.   The Letter of Credit shall be in addition to, and not in lieu of,
     Landlord's rights to require a letter of credit pursuant to section 10(d)
     of the Lease.

10.  This Agreement may be executed in any number of counterparts and by the
     different parties thereto on separate counterparts, each of which, when so
     executed, shall be deemed an original, but all counterparts shall
     constitute but one and the same instrument.


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11.  Each of Tenant and Landlord shall pay their own respective legal fees and
     expenses in preparing and reviewing this Agreement.

12.  If at any time the Letter of Credit is drawn and proceeds are held by
     Landlord (or its assignee) or Lender, Borrower shall have a right to
     substitute a letter of credit for the cash so held so long as such
     substitute letter of credit meets all of the terms and conditions of the
     Letter of Credit (except that the amount of such substitute letter of
     credit shall be in the amount of the cash so held). In such event, all
     references herein to the Letter of Credit shall be deemed to include any
     such substitute letter of credit.

          EXECUTED as of the day and year first above written.

                                        RANDOLPH/CLINTON LIMITED PARTNERSHIP, a
                                        Delaware limited partnership
                                        By: QRS 10-1(ILL), INC., general partner

                                        By
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                                        INFORMATION RESOURCES, INC., a
                                        Delaware corporation


                                        By
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