X0202 4/A 2007-10-17 2007-10-19 0 0001123647 ATP OIL & GAS CORP ATPG 0001167540 SCHLIEF GERALD W 4600 POST OAK PLACE SUITE 200 HOUSTON TX 77027 0 1 0 0 Senior Vice President Common Stock 2007-10-17 4 S 0 91393 54.85 D 951662 D Common Stock 2007-10-18 4 S 0 18607 54.5 D 933055 D Common Stock sold from Trust 2007-10-18 4 S 0 82917 54.53 D 850138 D Common Stock sold from Trust 2007-10-19 4 S 0 27083 53.72 D 823055 D This Total includes 110,000 shares of common stock that are indirectly owned by Mr. Schlief through a trust. This Total includes the remaining 27,083 shares of common stock that are indirectly owned by Mr. Schlief through a trust. The correct number of securities sold from the trust on 10/18/2007 is 82,917 shares and not 81,917 shares. This Form 4A is being filed to show the correct number of securities sold from the trust on 10/18/2007 as 82,917 shares instead of the 81,917 shares shown on the Form 4 of 10/19/2007. All other entries on the Form 4 of 10/19/2007 were correct and are repeated here for completeness. The total number of securities sold is 220,000 shares. Gerald W. Schlief 2007-10-23