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                                                                   EXHIBIT 99.11
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                               FIRST AMENDMENT TO
                              AMENDED AND RESTATED
                            STOCK PURCHASE AGREEMENT


         This First Amendment to Amended and Restated Stock Purchase Agreement
(the "FIRST AMENDMENT") is entered into as of June 4, 1999, by and between Lend
Lease Portfolio Management, Inc. ("LLPM") and American Realty Trust, Inc.
("ART").

                                R E C I T A L S:

         A. LLPM and ART entered into that certain Amended and Restated Stock
Purchase Agreement, dated as of August 25, 1998 (the "STOCK PURCHASE AGREEMENT")
relating to the sale of LLPM's Shares, as such term is defined in the Stock
Purchase Agreement, to ART.

         B. LLPM and ART desire to amend the Stock Purchase Agreement as set
forth herein.

                               A G R E E M E N T:

         NOW, THEREFORE, in consideration of the mutual promises set forth
herein, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto hereby agree as
follows:

         1. Amendment to Section 5.1 of the Stock Purchase Agreement. Section
5.1 of the Stock Purchase Agreement shall be amended by replacing the words
"December 15, 1998" in the seventh line of such section with the words "October
29, 1999", so that Section 5.1 reads as set forth in its entirety below:

                  "TERMINATION. Notwithstanding anything in this Agreement to
                  the contrary, this Agreement may be terminated only (A) by the
                  mutual written consent of the Purchaser and the Selling
                  Shareholder, (B) by either the Purchaser, on the one hand, or
                  the Selling Shareholder, on the other hand, at any time, in
                  the event of a breach by the other party which breach remains
                  uncured for ten (10) calendar days after notice in writing of
                  such breach is delivered to the breaching party, or (C) by
                  either the Purchaser, on the one hand, or the Selling
                  Shareholder, on the other hand, by written notice to the other
                  if the Closing has not occurred prior to October 29, 1999
                  unless the Closing has not occurred solely by reason of the
                  failure of the party seeking to terminate this Agreement to
                  perform or observe any of the covenants or agreements hereof
                  to be performed by such party prior thereto."

         2. Effect of Amendment; Amendment Controls. Except as expressly stated
herein, the provisions of the Stock Purchase Agreement in effect as of the date
of this First Amendment shall

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remain in full force and effect. To the extent this First Amendment is in
conflict with any provision of the Stock Purchase Agreement, as amended, the
terms of this First Amendment shall control.

         3. Binding Effect. The amendments contained in this First Amendment
shall inure to the benefit of the successors and assigns of the respective
parties hereto.

         4. Defined Terms. All capitalized terms used herein and not otherwise
defined herein shall have the meanings given to such terms in the Stock Purchase
Agreement.

         5. Governing Law. This First Amendment shall be governed by the
internal laws of the State of Georgia without giving effect to the conflict of
laws principles thereof.

         6. Counterparts. This First Amendment may be signed in any number of
counterparts, each of which, when taken together, shall constitute the original.

         IN WITNESS WHEREOF, the parties hereto have executed this First
Amendment as of the date first above written.

                                          SELLING SHAREHOLDER:

                                          LEND LEASE  PORTFOLIO MANAGEMENT, INC.


                                          By /s/ Samuel F. Hatcher
                                            ------------------------------------
                                          Name: Samuel F. Hatcher
                                               ---------------------------------
                                          Title: Vice President
                                                --------------------------------

                                          PURCHASER:

                                          AMERICAN REALTY TRUST, INC.



                                          By /s/ A. Cal Rossi, Jr.
                                            ------------------------------------
                                          Name: A. Cal Rossi, Jr.
                                               ---------------------------------
                                          Title: Vice President
                                                --------------------------------

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