X0306 4 2020-12-11 0 0001372020 Great Lakes Dredge & Dock CORP GLDD 0001658715 LaVoy Kathleen Mackie C/O GREAT LAKES DREDGE & DOCK CORP 2122 YORK ROAD OAK BROOK IL 60523 0 1 0 0 SVP & Chief Legal Officer Common Stock 2020-12-11 4 S 0 10000 11.4068 D 119687 D Common Stock 2020-12-11 4 M 0 6614 7.56 A 126301 D Common Stock 2020-12-11 4 S 0 6614 11.4175 D 125702 D Common Stock 2020-12-11 4 M 0 6015 7.62 A 132316 D Common Stock 2020-12-11 4 S 0 6015 11.407 D 119687 D Employee Stock Option 7.56 2020-12-11 4 M 0 6614 7.56 D 2023-05-07 Common Stock 6614 0 D Employee Stock Option 7.62 2020-12-11 4 M 0 6015 7.62 D 2024-05-09 Common Stock 6015 0 D Represents the weighted average price. The shares were sold in multiple transactions ranging from $11.39 to $11.43, inclusive. Upon request by the Commission staff, the issuer or security holder of the issuer, the reporting person will provide information regarding the number of shares disposed of at each separate price. Represents an exercise of vested employee stock options granted on May 7, 2013 under the Great Lakes Dredge & Dock Corporation 2007 Long-Term Incentive Plan. Represents the weighted average price. The shares were sold in multiple transactions ranging from $11.41 to $11.425 inclusive. Upon request by the Commission staff, the issuer or security holder of the issuer, the reporting person will provide information regarding the number of shares disposed of at each separate price. Represents an exercise of vested employee stock options granted on May 9, 2014 under the Great Lakes Dredge & Dock Corporation 2007 Long-Term Incentive Plan. Represents the weighted average price. The shares were sold in multiple transactions ranging from $11.40 to $11.411, inclusive. Upon request by the Commission staff, the issuer or security holder of the issuer, the reporting person will provide information regarding the number of shares disposed of at each separate price. The options vested in three equal installments beginning May 7, 2014. The options vested in three equal installments beginning May 9, 2015. Kathleen M. LaVoy 2020-12-15