0000893750-05-000038 3 1 20050119 20050119 20050119 OSTMEIER HANNS 0001314139 3 34 001-32410 05537556 972-443-4000 1601 W. LBJ FREEWAY DALLAS TX 75234 Celanese CORP 0001306830 2810 980420726 DE 1231 1601 W. LBJ FREEWAY DALLAS TX 75234 972-443-4000 1601 W. LBJ FREEWAY DALLAS TX 75234 Blackstone Crystal Holdings Capital Partners (Cayman) IV Ltd. 20041022 3 1 form3_ex.xml X0202 3 2005-01-19 1 0001306830 Celanese CORP CE 0001314139 OSTMEIER HANNS C/O THE BLACKSTONE GROUP 345 PARK AVENUE NEW YORK NY 10154 1 0 0 0 Mr. Ostmeier is associated with Blackstone LR Associates (Cayman) IV Ltd. ("BLRA"). BLRA may be deemed to be the beneficial owner of the shares of Series B common stock of Celanese Corporation for the following reason: 92,360,339 shares of Series B common stock of Celanese Corporation are owned by Blackstone Capital Partners (Cayman) Ltd. 1 ("Cayman 1"), Blackstone Capital Partners (Cayman) Ltd. 2 ("Cayman 2"), and Blackstone Capital Partners (Cayman) Ltd. 3 ("Cayman 3" and collectively with Cayman 1 and Cayman 2, the "Cayman Entities"). Blackstone Capital Partners (Cayman) IV L.P. ("BCP IV") owns 100% of Cayman 1. Blackstone Family Investment Partnership (Cayman) IV-A L.P. ("BFIP") and Blackstone Capital Partners (Cayman) IV-A L.P. ("BCP IV-A") collectively own 100% of Cayman 2. Blackstone Chemical Coinvest Partners (Cayman) L.P. ("BCCP" and, collectively with BCP IV, BFIP and BCP IV-A, the "Blackstone Funds") owns 100% of Cayman 3. Each of the Blackstone Funds may be deemed to be the beneficial owner of the shares of Series B common stock held by the Cayman Entities owned by such Blackstone Funds. Blackstone Management Associates (Cayman) IV L.P. ("BMA") is the general partner of each of the Blackstone Funds and may, therefore, be deemed to be the beneficial owner of the share of Series B common stock held by the Cayman Entities. BLRA is the general partner of BMA and may, therefore, be deemed to be the beneficial owner of shares of Series B common stock held by the Cayman Entities. Mr. Ostmeier disclaims beneficial ownership of shares of the Series B common stock that may be deemed beneficially owned by BLRA or any other affiliates of The Blackstone Group set forth above. This report shall not be deemed an admission that Mr. Ostmeier is the beneficial owner of, or has any pecuniary interest in, such securities for purposes of Section 16 of the Exchange Act of 1934, as amended, or for any other purpose. Hanns Ostmeier 2005-01-19