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                                                                  EXHIBIT 99.13

                              SECOND AMENDMENT TO
                            STOCK PURCHASE AGREEMENT


         This Second Amendment to Stock Purchase Agreement (the "SECOND
AMENDMENT") is entered into as of June 4, 1999, by and between Summit Venture,
L.P. ("SUMMIT") and American Realty Trust, Inc. ("ART").

                                R E C I T A L S:

         A. Summit and ART entered into that certain Stock Purchase Agreement,
dated as of August 26, 1998, as amended by that certain First Amendment to
Stock Purchase Agreement, dated as of May 14, 1999 (as so amended, the "STOCK
PURCHASE AGREEMENT") relating to the sale of Summit's Shares, as such term is
defined in the Stock Purchase Agreement, to ART.

         B. Summit 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
"July 31, 1999" in 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, (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, or (D) by the
            Selling Shareholder, by written notice to the Purchaser, if the
            Harrisburg East Mall is not sold by October 29, 1999 in substantial
            accordance with the terms described in EQK's press release dated
            March 5, 1999."

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

         3. Binding Effect. The amendments contained in this Second 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 Second 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 Second 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 Second
Amendment as of the date first above written.

                                       SELLING SHAREHOLDER:

                                       SUMMIT VENTURE, L.P.


                                       By /s/ Barry Zemel
                                          --------------------------------------
                                       Name: Barry Zemel
                                             -----------------------------------
                                       Title: G/P
                                              ----------------------------------


                                       PURCHASER:

                                       AMERICAN REALTY TRUST, INC.



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

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