[Form 4] Great Lakes Dredge & Dock CORP Insider Trading Activity

Rhea-AI Filing Summary

Kathleen M. Shanahan, a director of Great Lakes Dredge & Dock Corp (GLDD), reported transactions dated 09/30/2025. The filing shows a disposition of 70,524 shares of common stock and the grant and deferral of 2,106 Deferred Stock Units (DSUs) under the company’s Director Deferral Plan. The DSUs are payable in common stock on a 1-for-1 basis in three equal annual installments beginning January 15, 2026. Following the reported derivative transaction, the filing shows 12,777 shares beneficially owned by the reporting person in a direct ownership form. The report was signed by power of attorney on 10/01/2025 and lists the reporting person’s affiliation and Houston address as provided.

Insights

Corporate Governance Expert

TL;DR: Routine director compensation and a large share disposition were reported; DSUs convert to stock over three years.

The Form 4 discloses two routine actions: a sizeable disposition of 70,524 common shares and the award of 2,106 DSUs12,777 shares. No additional context about the reason for the disposition or price is provided in the filing.

Securities Compliance Analyst

TL;DR: Disclosure appears complete for Section 16 reporting: transaction dates, amounts, and DSU conversion schedule are specified.

The Form 4 includes required fields: reporting person identity and address, issuer and ticker (GLDD), transaction date (09/30/2025), and signature by power of attorney dated 10/01/2025. It specifies a disposition of 70,524 shares and an acquisition of 2,106 DSUs with the post-transaction beneficial ownership reported as 12,777 shares (direct). The DSU payout mechanics are explicitly stated. The filing does not include a transaction price for the disposed shares; that information is not provided in the document.

10/01/2025 - 05:02 PM

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

Shanahan Kathleen M

(Last) (First) (Middle)

C/O GREAT LAKES DREDGE & DOCK CORP.

9811 KATY FREEWAY, SUITE 1200

(Street)

HOUSTON TX 77024

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Great Lakes Dredge & Dock CORP [ GLDD ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
09/30/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock								70,524	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Deferred Stock Units	(1)	09/30/2025		A		2,106		(1)	(1)	Common Stock	2,106	$0	12,777	D

Explanation of Responses:

1. Deferred Stock Units ("DSUs") granted September 30, 2025 and deferred pursuant to the Company's Director Deferral Plan. The DSUs will be payable in common stock on a 1-for-1 basis in three equal annual installments beginning January 15, 2026.

	/s/Vivienne R. Schiffer, by Power of Attorney	10/01/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What transactions did Kathleen M. Shanahan report on Form 4 for GLDD?

She reported a disposition of 70,524 common shares2,106 Deferred Stock Units (DSUs).

How will the DSUs awarded to the director be paid?

DSUs will be paid in common stock on a 1-for-1 basis in three equal annual installments

What is the reporting person’s beneficial ownership after the transactions?

The filing reports 12,777 shares beneficially owned

When were the transactions and when was the Form 4 signed?

Transactions dated: 09/30/2025. Form signed (by power of attorney): 10/01/2025.

Does the Form 4 disclose the price for the 70,524 shares disposed?

No price is provided