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Washington, D.C. 20549


Proxy Statement Pursuant to Section 14(a) of
the Securities Exchange Act of 1934 (Amendment No.           )

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    Filed by Chelsea Property Group, Inc.
Pursuant to Rule 14a-6
under the Securities Exchange Act of 1934
Subject Company: Chelsea Property Group,
Commission File No.: 1-12328

Important Legal Information

        This communication is being made in respect of the proposed merger involving Chelsea Property Group, Inc. ("Chelsea") and Simon Property Group, Inc. ("Simon"). In connection with the proposed merger, Simon filed an amended registration statement on Form S-4 on September 9, 2004 containing a definitive proxy statement/prospectus for the stockholders of Chelsea. Chelsea began mailing the definitive proxy statement/prospectus and form of proxy to its stockholders on September 9, 2004. Before making any voting or investment decision, Chelsea's stockholders and investors are urged to read the definitive proxy statement/prospectus regarding the merger, as well as any other relevant documents carefully in their entirety because they will contain important information about the proposed transaction. The definitive proxy statement/prospectus on file with the SEC and other relevant materials are available free of charge at the SEC's Web site, www.sec.gov. Stockholders and investors in Chelsea or Simon will also be able to obtain the definitive proxy statement/prospectus and other documents free of charge by directing their requests to:

Chelsea Property Group, Inc.
Investor Relations
105 Eisenhower Parkway
Roseland, New Jersey 07068
  Simon Property Group, Inc.
Investor Relations
National City Center
115 West Washington Street, Suite 15 East
Indianapolis, Indiana 46204

        The following letter was sent to certain stockholders of Chelsea on September 30, 2004.

Chelsea Property Group, Inc.
105 Eisenhower Parkway
Roseland, NJ 07068

September 30, 2004


Dear Shareholder:

        Our records reflect that you have not yet voted your proxy for the October 13, 2004 Special Meeting of Shareholders. At the meeting, you will be asked to vote upon the proposal to approve the REIT merger and the merger agreement, pursuant to which Simon Acquisition I, LLC, a Maryland limited liability company and an indirect subsidiary of Simon Property Group, Inc., a Delaware corporation, will be merged with and into Chelsea Property Group, Inc., a Maryland corporation. In the proposed REIT Merger, Chelsea will become an indirect subsidiary of Simon. For each share of Chelsea common stock that you own, you will receive (subject to adjustment as described in the proxy statement/prospectus previously sent to you):

        As explained in the proxy statement/prospectus previously sent to you, the Board of Directors of Chelsea recommends a vote FOR this proposal. The adoption of this critical proposal requires the affirmative vote of at least two-thirds of the outstanding shares of Chelsea common stock. Not voting has the same effect as a vote against the proposal.

        Last week Institutional Shareholder Services (ISS), the world premier proxy advisory firm, issued their recommendation in favor of the merger agreement. ISS issues voting recommendations to their client base of institutional investors regarding thousands of corporations each year.

        For your convenience we have made arrangements for you to vote by telephone or the internet in addition to voting by mail. Just follow the directions on the enclosed proxy. If you have any questions, or require assistance in voting, please call MacKenzie Partners, Inc. at (800) 322-2885 (Toll Free) or (212) 929-5500 (Call Collect). Thank you for your support.


David C. Bloom
Chairman and Chief Executive Officer


Chelsea Property Group, Inc. 105 Eisenhower Parkway Roseland, NJ 07068