X0306 4 2012-09-28 0 0001372020 Great Lakes Dredge & Dock CORP GLDD 0001317779 Leight Nathan GREAT LAKES DREDGE & DOCK CORPORATION 2122 YORK ROAD OAK BROOK IL 60523 1 0 0 0 Common Stock 2012-09-28 4 A 0 10633 0 A 1624898 D Common Stock 367250 I Common Stock Held by the Leight Family Irrevocable Trust Common Stock 4000 I Common Stock Held by various family trusts 1000 shares of common stock are owned by Bruce Leight UGMA (Mr.Leight's son is the beneficiary), 1000 shares are owned by Jennifer Leight UGMA (Mr.Leight's daughter is the beneficiary), 1000 shares are owned by Keight Leight UGMA (Mr.Leight's son is the beneficiary), and 1000 shares are owned by Lillianne Leight UGMA (Mr.Leight's daughter is the beneficiary). Mr.Leight serves as a trustee or co-trustee of those trusts. As Chairman of the Board , Mr. Leight received an additional 8,117 shares as compensation in such capacity. /s/ Nathan D. Leight 2012-10-01