X0609 4 2026-03-31 true 0001372020 Great Lakes Dredge & Dock CORP GLDD 0001249072 DICKERSON LAWRENCE R false C/O GREAT LAKES DREDGE & DOCK CORP. 9811 KATY FREEWAY, SUITE 1200 HOUSTON TX 77024 true false false false false Common Stock 2026-04-01 4 U false 86217 D 0 D Deferred Stock Units 2026-03-31 4 A false 2938 0 A common stock 2938 76962 D Deferred Stock Units 17.00 2026-04-01 4 D false 76962 D common stock 76962 0 D Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated February 10, 2026, by and among Saltchuk Resources, Inc. ("Parent"), Huron MergeCo, Inc. ("Merger Sub"), and Great Lakes Dredge & Dock Corporation ("Issuer") on April 1, 2026 (the "Effective Time"), Merger Sub merged with and into Issuer, with Issuer surviving as a wholly owned subsidiary of Parent upon consummation of the transactions contemplated by the Merger Agreement. At the Effective Time, each outstanding share of common stock of the Issuer ("Common Stock") was cancelled and converted into the right to receive $17.00 in cash (the "Merger Consideration"), without interest and subject to any required tax withholdings. Deferred Stock Units ("DSUs") granted March 31, 2026 and deferred pursuant to the Issuer's Director Deferral Plan. Includes 76,962 DSUs. At the Effective Time, each outstanding award of DSUs was canceled and converted into the right to receive an amount in cash equal to the product of the aggregate number of shares of Common Stock underlying such DSU immediately prior to the Effective Time, multiplied by the Merger Consideration. /s/Vivienne R. Schiffer, by Power of Attorney 2026-04-01