Great Lakes Dredge & Dock (GLDD) removes 18.7M registered shares after merger

Rhea-AI Filing Summary

Great Lakes Dredge & Dock Corporation filed a Post-Effective Amendment to its Form S-3 to terminate and deregister any unsold securities previously registered under Registration No. 333-153207, which had covered 18,695,334 shares of common stock. The amendment follows the closing of a merger under an Agreement and Plan of Merger with Saltchuk Resources, Inc., completed on April 1, 2026, after which the company became a wholly owned subsidiary of the acquiring parent. The filing states the company is removing from registration all unsold securities covered by the registration statement in accordance with its prior undertaking.

Key Figures

Registered shares removed: 18,695,334 shares Merger closing date: April 1, 2026 Registration statement: No. 333-153207

3 metrics

Registered shares removed 18,695,334 shares Registered under Registration No. 333-153207

Merger closing date April 1, 2026 Merger with Saltchuk Resources, Inc.

Registration statement No. 333-153207 Form S-3 originally filed August 26, 2008

Key Terms

Post-Effective Amendment, Registration Statement, Agreement and Plan of Merger, deregister

4 terms

Post-Effective Amendment regulatory

"filing this post-effective amendment (this “Post-Effective Amendment”) to Registration Statement"

A post-effective amendment is an official update to a securities registration document filed after that document has become effective with regulators; it corrects, adds or replaces information about the securities, the company, or an offering. Investors care because it keeps the legal record current and can change what is being sold or the rights attached to shares — like getting a revised product manual after a launch that may affect value or use.

Registration Statement regulatory

"Registration Statement No. 333-153207 (the “Registration Statement”)"

A registration statement is a formal document that companies file with a government agency to offer new shares of stock to the public. It provides essential information about the company's finances, operations, and risks, helping investors make informed decisions. Think of it as a detailed product description that ensures transparency and trust before buying into a company.

Agreement and Plan of Merger other

"entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Saltchuk Resources, Inc."

An Agreement and Plan of Merger is a formal document where two companies agree to combine into one, outlining how the process will happen. It’s like a step-by-step plan for merging, and it matters because it shows both sides have agreed on the details before the official transition takes place.

deregister regulatory

"hereby terminates the effectiveness of the Registration Statement and removes from registration"

Deregister is the act of removing a company’s securities from a public regulatory registry or ending their listing on a stock exchange; think of it like taking a car off public roads so it no longer needs public inspections. For investors, deregistration matters because it usually reduces required public disclosures, can make shares harder to buy or sell, and increases uncertainty about the company’s finances and governance due to lower transparency and liquidity.

As filed with the Securities and Exchange Commission on April 1, 2026

Registration No. 333-153207

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

POST-EFFECTIVE AMENDMENT NO. 2 TO FORM S-3

REGISTRATION STATEMENT NO. 333-153207

UNDER

THE SECURITIES ACT OF 1933

GREAT LAKES DREDGE & DOCK CORPORATION

(Exact name of registrant as specified in its charter)

Delaware		20-5336063
(State or other jurisdiction of incorporation or organization)		(I.R.S. Employer Identification Number)

9811 Katy Freeway, Suite 1200

Houston, Texas 77024

(346) 359-1010

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Scott Kornblau

Senior Vice President and Chief Financial Officer

Great Lakes Dredge & Dock Corporation

9811 Katy Freeway, Suite 1200

Houston, Texas 77024

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Philip Richter

Ryan Messier

Fried, Frank, Harris, Shriver & Jacobson LLP

One New York Plaza

New York, NY 10004

(212) 859-8000

Approximate date of commencement of proposed sale to the public: Not applicable.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box. ☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box. ☐

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box. ☐

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer		☒		Accelerated filer		☐
Non-accelerated filer		☐		Smaller reporting company		☐
				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 7(a)(2)(B) of the Securities Act. ☐

DEREGISTRATION OF SECURITIES

Great Lakes Dredge & Dock Corporation, a Delaware corporation (the “Company”), is filing this post-effective amendment (this “Post-Effective Amendment”) to Registration Statement No. 333-153207 (the “Registration Statement”), which was previously filed with the United States Securities and Exchange Commission (the “SEC”) on August  26, 2008, as amended by the Post-Effective Amendment No. 1 (No. 333-153207), previously filed with the SEC on November 25, 2009, pertaining to the registration of up to 18,695,334 shares of the Company’s common stock, par value $0.0001 per share, offered for resale by selling stockholders from time to time, as described therein, to deregister any and all securities registered but unsold under the Registration Statement as of the date hereof.

On February 10, 2026, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Saltchuk Resources, Inc., a Washington corporation (“Parent”), and Huron MergeCo., Inc., a Delaware corporation and a wholly owned subsidiary of Parent (“Merger Sub”). On April 1, 2026, pursuant to the Merger Agreement, Merger Sub merged with and into the Company, with the Company surviving as a wholly owned subsidiary of Parent (the “Merger”).

As a result of the Merger and the other transactions contemplated by the Merger Agreement, the Company has terminated all offerings of the Company’s securities registered pursuant to its existing registration statements under the Securities Act of 1933, as amended, including the Registration Statement. The Company, by filing this Post-Effective Amendment, hereby terminates the effectiveness of the Registration Statement and removes from registration any and all securities registered for issuance under the Registration Statement that remain unsold as of the date hereof. This filing is made in accordance with an undertaking made by the Company in the Registration Statement to remove from registration by means of a post-effective amendment any securities that had been registered for issuance that remain unsold at the termination of the offering.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this Post-Effective Amendment to the Registration Statement on Form S-3 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Houston, State of Texas, on this April 1, 2026.

GREAT LAKES DREDGE & DOCK CORPORATION
By:		/s/ Scott Kornblau
		Name:  Scott Kornblau
		Title:   Senior Vice President and Chief Financial Officer

No other person is required to sign this Post-Effective Amendment in reliance upon Rule 478 under the Securities Act of 1933, as amended.

FAQ

What did GLDD deregister in the April 1, 2026 filing?

The company deregistered 18,695,334 shares of common stock that remained unsold under Registration No. 333-153207. The removal was accomplished through a post-effective amendment to the prior Form S-3 registration statement.

Why did Great Lakes Dredge & Dock (GLDD) remove the registered shares?

The deregistration occurred because GLDD completed a merger with Saltchuk Resources, Inc., on April 1, 2026. Following the Merger, GLDD became a wholly owned subsidiary, and the company terminated offerings registered under its existing registration statements.

Does the filing indicate any remaining public offering activity for GLDD?

No. The filing states the company has terminated all offerings registered under its existing registration statements and removed any unsold securities from registration as of the amendment date.

Which registration statement number was affected by the post-effective amendment?

The post-effective amendment terminates Registration Statement No. 333-153207, which originally registered up to 18,695,334 shares for resale by selling stockholders.

Who executed the post-effective amendment for GLDD?

The amendment was signed by Scott Kornblau, Senior Vice President and Chief Financial Officer of Great Lakes Dredge & Dock Corporation, on April 1, 2026.