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                                                                   EXHIBIT 10.18



                               FOURTH AMENDMENT TO
               SECOND AMENDED AND RESTATED OPERATING AGREEMENT OF
                                  GGPLP L.L.C.

         THIS FOURTH AMENDMENT (the "Fourth Amendment") is made and entered into
on the seventh day of April, 2003, by and among the undersigned parties.

                              W I T N E S S E T H:
                              - - - - - - - - - -

         WHEREAS, a Delaware limited liability company known as GGPLP L.L.C.
(the "Company") exists pursuant to the Delaware Limited Liability Company Act
and that certain Second Amended and Restated Operating Agreement dated April 17,
2002, as amended by the prior amendments thereto (the "Restated Agreement"),
including without limitation that certain Third Amendment thereto dated October
30, 2002 (the "Third Amendment"); and

         WHEREAS, the parties hereto, being all of the holders of Common Units,
Series A Preferred Units and Series B Preferred Units (as such terms are defined
in the Restated Agreement), desire to amend the Restated Agreement to correct
certain errors contained in the Restated Agreement.

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
herein contained and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto do hereby agree
as follows:

         1. CAPITALIZED TERMS. Capitalized terms used but not defined herein
shall have the definitions assigned to such terms in the Restated Agreement, as
amended hereby.

         2. AMENDMENT TO DEFINITION OF "CONSOLIDATED TANGIBLE NET WORTH". The
definition of "Consolidated Tangible Net Worth" in Article I of the Restated
Agreement is hereby deleted and the following is hereby inserted in lieu
thereof:

                           "`Consolidated Tangible Net Worth' shall mean, as of
                  any date of determination, the excess, without duplication, of
                  (a) Consolidated Tangible Value as of such date over (b)
                  Consolidated Outstanding Indebtedness as of such date."

         3. ADDITION OF DEFINITION OF "CONSOLIDATED TANGIBLE VALUE". The
following new definition is hereby added after the definition of "Consolidated
Tangible Net Worth" in Article I of the Restated Agreement:

                           "`Consolidated Tangible Value' shall mean, as of any
                  date of determination, without duplication, the total fair
                  market value of the assets (including cash and cash
                  equivalents) of the Consolidated Group and the applicable
                  Consolidated Group Pro Rata Shares of the assets of the
                  Investment Affiliates as of such date; provided, that for
                  purposes of this definition, the determination of total assets
                  shall exclude (a) all assets which in accordance with GAAP
                  should be classified as intangible assets




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                  (such as goodwill, patents, trademarks, copyrights,
                  franchises, unamortized debt discount, capitalized research
                  and development costs, capitalized software costs and
                  organization costs), (b) cash held in a sinking or other
                  similar fund established for the purpose of redemption or
                  other retirement of capital stock and (c) to the extent not
                  already deducted from total assets, reserves for depreciation,
                  depletion, obsolescence or amortization of properties and
                  other reserves or appropriations of retained earnings which
                  have been established or which a prudent owner and operator
                  should establish in connection with the business of operating
                  and maintaining the Company properties. For purposes of the
                  calculation of Consolidated Tangible Value, (a) the fair
                  market value of income producing real property shall be the
                  quotient of four times the Net Operating Income of such
                  property for the most recently completed calendar quarter
                  divided by an 8.25% capitalization rate, (b) the fair market
                  value of any raw land, vacant out-parcel or real estate under
                  construction shall equal the aggregate sums expended therefor
                  (including without limitation land acquisition costs)
                  (provided, however, that (i) the fair market value of the land
                  portion of those assets which are listed on Schedule 1 to the
                  Term Loan Agreement shall be as set forth on such Schedule 1
                  and (ii) no amount shall be included under this clause (b)
                  with respect to real estate under construction if the Company
                  has included income therefrom in the calculation of Net
                  Operating Income unless the construction in question involves
                  renovation or expansion of a property that is otherwise
                  completed, open for business and operational, the construction
                  in question will not materially interrupt, limit or impair
                  such ongoing business and operations and the inclusion of such
                  income in the calculation of Net Operating Income and such
                  costs and/or other amounts under this clause (b) is not
                  duplicative) and (c) the fair market value of any other asset
                  shall be the lesser of cost and fair market value (as
                  determined in good faith by the Managing Member) thereof."

         4. AMENDMENT TO DEFINITION OF "PARENT INDEBTEDNESS". The definition of
"Parent Indebtedness" in Article I of the Restated Agreement is hereby deleted
and the following is hereby inserted in lieu thereof:

                           "`Parent Indebtedness' shall mean, as of the time of
                  determination, the then outstanding aggregate Indebtedness of
                  the Parent Group but excluding (a) any guarantee obligations
                  of Parent Group in respect of primary obligations of the
                  Company or any of its Subsidiaries or Investment Affiliates
                  and (b) Indebtedness allocated to the members of the
                  Consolidated Group and/or the Investment Affiliates pursuant
                  to (i) any of the sharing agreements referred to on Schedule
                  3.aa to the Purchase Agreement and/or (ii) the letter
                  agreement dated the date hereof, between the Company and the
                  Operating Partnership, relating to the Term Loan Agreement."


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         5. AMENDMENT TO SECTION 4.3(i)(i)(C) AND SECTION 9(a)(iii) OF SCHEDULE
B. The text of each of Section 4.3(i)(i)(C) of the Restated Agreement and
Section 9(a)(iii) of Schedule B of the Restated Agreement is hereby deleted and
the following is hereby inserted in lieu thereof:

                           "Loan to Value Ratio. The ratio of (x) the
                  Consolidated Outstanding Indebtedness to (y) the Consolidated
                  Tangible Value is no greater than 0.75 to 1.0;"

         6. EFFECTIVE DATE; OTHER PROVISIONS UNAFFECTED. This Fourth Amendment
and Sections 3 and 4 of the Third Amendment are effective retroactive to April
17, 2002 (it being acknowledged that certain of the changes effected by Section
4 hereof were also effected by Sections 3 and 4 of the Third Amendment). Except
as expressly amended hereby, the Restated Agreement shall remain in full force
and effect in accordance with its terms.

         7. COUNTERPARTS. This Fourth Amendment may be executed in counterparts,
each of which shall be an original, but all of which shall constitute one and
the same document and all signatures need not appear on the same page.

         IN WITNESS WHEREOF, the parties hereto have executed this Fourth
Amendment on the day and year first above written.


                                         MANAGING MEMBER:

                                         GGP LIMITED PARTNERSHIP, a Delaware
                                         limited partnership

                                         By:  General Growth Properties, Inc.,
                                              a Delaware corporation, its
                                              general partner




                                              By: /s/ Bernard Freibaum
                                                 -------------------------------
                                                 Name: Bernard Freibaum
                                                      --------------------------
                                                 Title: Executive Vice President
                                                       -------------------------

                                         CERTAIN OTHER MEMBERS:

                                         CALEDONIAN HOLDING COMPANY, INC., a
                                         Delaware corporation

                                         By:  /s/ Bernard Freibaum
                                            ------------------------------------
                                            Name: Bernard Freibaum
                                                 -------------------------------
                                            Title: Vice President
                                                  ------------------------------


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                                   GGP AMERICAN PROPERTIES INC., a
                                   Delaware corporation

                                   By:  /s/ Bernard Freibaum
                                      ------------------------------------------
                                      Name: Bernard Freibaum
                                           -------------------------------------
                                      Title: Vice President
                                            ------------------------------------



                                   GSEP 2000 REALTY CORP.

                                   By:  /s/ Eric S. Lane
                                      ------------------------------------------
                                      Name: Eric S. Lane
                                           -------------------------------------
                                      Title: President & Chief Executive Officer
                                            ------------------------------------


                                   GSEP 2002 REALTY CORP.

                                   By:  /s/ Eric S. Lane
                                      ------------------------------------------
                                      Name: Eric S. Lane
                                           -------------------------------------
                                      Title: President & Chief Executive Officer
                                            ------------------------------------


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