Celanese Corporation Announces Stockholder Offering Priced

DALLAS, Texas, December 15, 2005 – Celanese Corporation (NYSE: CE) announced today that it was informed that certain of its stockholders had priced an offering of 5,000,000 shares of its class A common stock. The selling stockholders have also granted to the underwriter of this offering an over-allotment option to purchase up to an additional 750,000 shares of class A common stock. All of the remaining shares of class A common stock held by the selling stockholders after this offering will be subject to a 60-day “lock-up” period. Selling stockholders will receive $90,000,000 aggregate proceeds from this offering ($103,500,000 if the underwriter’s over-allotment option is exercised in full). The Company will not receive any of the proceeds from the offering. Credit Suisse First Boston is acting as the sole book-running manager and the sole underwriter for this offering.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy, nor shall there be any sale of these securities in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such state or jurisdiction.

A prospectus supplement relating to the offering will be filed with the Securities and Exchange Commission. When available, copies of the prospectus supplement and accompanying base prospectus relating to the offering may be obtained by contacting: Credit Suisse First Boston LLC, Eleven Madison Avenue, New York, New York 10010- 3629.

Celanese Corporation (NYSE:CE) is an integrated global producer of value-added industrial chemicals based in Dallas, Texas. The Company has four major businesses: Chemicals Products, Technical Polymers Ticona, Acetate Products and Performance Products. Celanese has production plants in 13 countries, including facilities in North America, Europe and Asia. In 2004, Celanese Corporation and its predecessor had combined net sales of $5.1 billion. The presentation of combined net sales of Celanese Corporation with its predecessor is not in accordance with U.S. GAAP. For more information on Celanese Corporation including a reconciliation of the combined net sales, please visit the company’s web site at www.celanese.com.

Forward-looking statements (statements which are not historical facts) in this release are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Investors are cautioned that all forwardlooking statements involve risks and uncertainties, including those risks and uncertainties detailed in the Company’s filings with the Securities and Exchange Commission, copies of which are available from the Company.