GLDD

Form 8-KFalse000137202000013720202026-02-232026-02-23iso4217:USDxbrli:sharesiso4217:USDxbrli:shares

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported):  February 23, 2026

Great Lakes Dredge & Dock Corporation (Exact name of registrant as specified in its charter)

Delaware001-3322520-5336063 (State or Other Jurisdiction of Incorporation)(Commission File Number)(I.R.S. Employer Identification No.) 9811 Katy Freeway, Suite 1200 Houston, Texas 77024 (Address of Principal Executive Offices) (Zip Code) (346) 359-1010 (Registrant's telephone number, including area code)

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: ☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act: Title of each classTrading Symbol(s)Name of each exchange on which registered Common Stock (Par Value $0.0001)GLDDNasdaq Stock Market, LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02. Results of Operations and Financial Condition.

On February 23, 2026, Great Lakes Dredge & Dock Corporation issued an earnings release announcing its financial results for the three and twelve months ended December 31, 2025. A copy of the earnings release is furnished as Exhibit 99.1 and incorporated herein by reference.

The information in this Form 8-K and Exhibit 99.1 are furnished pursuant to Item 2.02 of this Form 8-K and shall not be deemed filed for purposes of Section 18 of the Securities Exchange Act of 1934 or incorporated by reference in any filings under the Securities Act of 1933 or the Securities Exchange Act of 1934, except as shall be expressly set forth by specific reference in any such filing.

Item 9.01. Financial Statements and Exhibits.

(d)           Exhibits

The following exhibit is furnished herewith:

99.1 Earnings Release of Great Lakes Dredge & Dock Corporation dated February 23, 2026, announcing financial results for the three and twelve months ended December 31, 2025. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Great Lakes Dredge & Dock Corporation

Date: February 23, 2026By: /s/ SCOTT KORNBLAU Scott Kornblau Senior Vice President and Chief Financial Officer

Form 8-KFalse000137202000013720202025-11-042025-11-04iso4217:USDxbrli:sharesiso4217:USDxbrli:shares

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported):  November 4, 2025

Great Lakes Dredge & Dock Corporation (Exact name of registrant as specified in its charter)

Delaware001-3322520-5336063 (State or Other Jurisdiction of Incorporation)(Commission File Number)(I.R.S. Employer Identification No.) 9811 Katy Freeway, Suite 1200 Houston, Texas 77024 (Address of Principal Executive Offices) (Zip Code) (346) 359-1010 (Registrant's telephone number, including area code)

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: ☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act: Title of each classTrading Symbol(s)Name of each exchange on which registered Common Stock (Par Value $0.0001)GLDDNasdaq Stock Market, LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02. Results of Operations and Financial Condition.

On November 4, 2025, Great Lakes Dredge & Dock Corporation issued an earnings release announcing its financial results for the three months ended September 30, 2025, and announcing a conference call and webcast to be held at 9:00 a.m. (C.S.T.) on Tuesday, November 4, 2025, to discuss these results. A copy of the earnings release is furnished as Exhibit 99.1 and incorporated herein by reference.

The information in this Form 8-K and Exhibit 99.1 are furnished pursuant to Item 2.02 of this Form 8-K and shall not be deemed filed for purposes of Section 18 of the Securities Exchange Act of 1934 or incorporated by reference in any filings under the Securities Act of 1933 or the Securities Exchange Act of 1934, except as shall be expressly set forth by specific reference in any such filing.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

The following exhibit is furnished herewith:

99.1 Earnings Release of Great Lakes Dredge & Dock Corporation dated November 4, 2025, announcing financial results for the three months ended September 30, 2025. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Great Lakes Dredge & Dock Corporation

Date: November 4, 2025By: /s/ SCOTT KORNBLAU Scott Kornblau Senior Vice President and Chief Financial Officer

EXHIBIT INDEX

Number Exhibit

99.1 Earnings Release of Great Lakes Dredge & Dock Corporation dated November 4, 2025, announcing financial results for the three months ended September 30, 2025. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

Form 8-KFalse000137202000013720202025-08-052025-08-05iso4217:USDxbrli:sharesiso4217:USDxbrli:shares

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported):  August 5, 2025

Great Lakes Dredge & Dock Corporation (Exact name of registrant as specified in its charter)

Delaware001-3322520-5336063 (State or Other Jurisdiction of Incorporation)(Commission File Number)(I.R.S. Employer Identification No.) 9811 Katy Freeway, Suite 1200 Houston, Texas 77024 (Address of Principal Executive Offices) (Zip Code) (346) 359-1010 (Registrant's telephone number, including area code)

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: ☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act: Title of each classTrading Symbol(s)Name of each exchange on which registered Common Stock (Par Value $0.0001)GLDDNasdaq Stock Market, LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02. Results of Operations and Financial Condition.

On August 5, 2025, Great Lakes Dredge & Dock Corporation issued an earnings release announcing its financial results for the three months ended June 30, 2025 and announcing a conference call and webcast to be held at 9:00 a.m. (C.D.T.) on Tuesday, August 5, 2025 to discuss these results. A copy of the earnings release is furnished as Exhibit 99.1 and incorporated herein by reference.

The information in this Form 8-K and Exhibit 99.1 are furnished pursuant to Item 2.02 of this Form 8-K and shall not be deemed filed for purposes of Section 18 of the Securities Exchange Act of 1934 or incorporated by reference in any filings under the Securities Act of 1933 or the Securities Exchange Act of 1934, except as shall be expressly set forth by specific reference in any such filing.

Item 9.01. Financial Statements and Exhibits.

(d)       Exhibits

The following exhibit is furnished herewith:

99.1 Earnings Release of Great Lakes Dredge & Dock Corporation dated August 5, 2025 announcing financial results for the three months ended June 30, 2025. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Great Lakes Dredge & Dock Corporation

Date: August 5, 2025By: /s/ SCOTT KORNBLAU Scott Kornblau Senior Vice President and Chief Financial Officer