Konstantakopoulos reports 4.9% Seanergy stake

A major shareholder associated with Seanergy Maritime Holdings Corp. reports 4.9% beneficial ownership of the company’s common stock through an affiliated entity.

Rhea-AI Filing Summary

Seanergy Maritime Holdings Corp. (SHIP) received an amended Schedule 13G from investor Konstantinos Konstantakopoulos and Longshaw Maritime Investments S.A. reporting their current beneficial ownership in the company’s common stock.

The filing states that Konstantakopoulos and Longshaw Maritime Investments S.A. beneficially own 1,063,079 shares of common stock, representing 4.9% of the class, based on 21,668,198 shares outstanding as of August 6, 2026. All shares are held indirectly through Longshaw Maritime Investments S.A., with no sole voting or dispositive power and shared voting and dispositive power over all 1,063,079 shares.

Key Figures

Shares beneficially owned: 1,063,079 shares Percent of class beneficially owned: 4.9% Shares outstanding baseline: 21,668,198 shares +3 more

6 metrics

Shares beneficially owned 1,063,079 shares Common stock of Seanergy Maritime Holdings Corp. reported in Schedule 13G/A

Percent of class beneficially owned 4.9% Ownership percentage of common stock attributed to each of Konstantinos Konstantakopoulos and Longshaw Maritime Investments S.A.

Shares outstanding baseline 21,668,198 shares Common shares outstanding used to calculate the 4.9% ownership, as of August 6, 2026 Form 6-K

Sole voting power 0 shares Number of SHIP shares over which the filer has sole power to vote

Shared voting power 1,063,079 shares Shares over which the filer has shared power to vote

Shared dispositive power 1,063,079 shares Shares over which the filer has shared power to dispose or direct disposition

Key Terms

beneficially owned, shared voting power, shared dispositive power, percent of class, +1 more

5 terms

beneficially owned financial

"Item 4. | Ownership (a) | Amount beneficially owned: 1,063,079"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

shared voting power financial

"6 | Shared Voting Power 1,063,079.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

shared dispositive power financial

"8 | Shared Dispositive Power 1,063,079.00"

percent of class financial

"(b) | Percent of class: 4.9%"

Percent of class is the portion of a specific category of securities—such as a company’s common shares, preferred shares, or a bond series—that takes part in or approves a corporate action (vote, consent, tender, etc.). Investors watch this number because it reveals how much support or opposition exists within that particular shareholder group; like counting how many members of a club back a proposal, it can determine whether a plan passes or how influence is distributed.

Schedule 13G regulatory

"Ownership of 5 percent or less of a class "

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What percentage of Seanergy Maritime Holdings (SHIP) shares does Konstantinos Konstantakopoulos report owning?

Konstantinos Konstantakopoulos reports beneficial ownership of 4.9% of Seanergy Maritime Holdings Corp.’s common stock, held indirectly through Longshaw Maritime Investments S.A., according to the amended Schedule 13G/A.

How many SHIP shares are beneficially owned by Konstantinos Konstantakopoulos and Longshaw Maritime Investments S.A.?

They report beneficial ownership of 1,063,079 shares of Seanergy Maritime Holdings Corp. common stock, all held indirectly through Longshaw Maritime Investments S.A., with shared voting and dispositive power over these shares.

What share count did SHIP use to calculate the 4.9% ownership in this Schedule 13G/A?

The 4.9% ownership is calculated based on an aggregate of 21,668,198 shares outstanding of Seanergy Maritime Holdings Corp. common stock, as reported in a Form 6-K filed on August 6, 2026.

Does Konstantinos Konstantakopoulos hold SHIP shares directly or indirectly?

He holds Seanergy Maritime Holdings Corp. shares indirectly. All 1,063,079 shares are owned through Longshaw Maritime Investments S.A., a Marshall Islands corporation controlled by him.

What voting and dispositive powers are reported for the SHIP shares in this 13G/A?

The filing reports 0 shares with sole voting or dispositive power and 1,063,079 shares with shared voting and shared dispositive power for both Konstantinos Konstantakopoulos and Longshaw Maritime Investments S.A.

What class of Seanergy Maritime (SHIP) securities is covered in this Schedule 13G/A amendment?

The amendment covers Common Stock, par value $0.0001 per share, of Seanergy Maritime Holdings Corp., identified by CUSIP Y73760400.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/21/2026 - 04:09 PM Accepted by SEC EDGAR 09/21/2026 - 04:08 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 5)

Seanergy Maritime Holdings Corp.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

Y73760400

(CUSIP Number)

09/18/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): Y73760400

1

Names of Reporting Persons

Konstantakopoulos Konstantinos

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

GREECE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,063,079.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,063,079.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,063,079.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

4.9 %

12

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person: Note to Row 6: Konstantinos Konstantakopoulos owns all 1,063,079 shares indirectly through Longshaw Maritime Investments S.A., a Marshall Islands corporation. Note to Row 11: The percent ownership is calculated based upon an aggregate of 21,668,198 shares outstanding as reported in Seanergy Maritime Holdings Corp.'s report on Form 6-K filed on August 6, 2026.

SCHEDULE 13G

CUSIP Number(s): Y73760400

1

Names of Reporting Persons

Longshaw Maritime Investments S.A.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

MARSHALL ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,063,079.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,063,079.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,063,079.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

4.9 %

12

Type of Reporting Person (See Instructions)

CO

Comment for Type of Reporting Person: Note to Row 6: Longshaw Maritime Investments S.A. is controlled by Konstantinos Konstantakopoulos, resulting in his indirect ownership of all 1,063,079 shares of common stock of Seanergy Maritime Holdings Corp. Note to Row 11: The percent ownership is calculated based upon an aggregate of 21,668,198 shares outstanding as reported in Seanergy Maritime Holdings Corp.'s report on Form 6-K filed on August 6, 2026.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Seanergy Maritime Holdings Corp.
(b)	Address of issuer's principal executive offices: 154 Vouliagmenis Avenue, 166 74 Glyfada, Greece
Item 2.
(a)	Name of person filing: Konstantinos Konstantakopoulos Longshaw Maritime Investments S.A.
(b)	Address or principal business office or, if none, residence: The principal business office of each person named in Item 2(a) above is: 60 Zephyrou Street & Syngrou Avenue 17564 Athens, Greece
(c)	Citizenship: Konstantinos Konstantakopoulos is a citizen of Greece. Longshaw Maritime Investments S.A. is a Marshall Islands Corporation.
(d)	Title of class of securities: Common Stock, par value $0.0001 per share
(e)	CUSIP No.: Y73760400
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 1. Konstantinos Konstantakopoulos - 1,063,079 2. Longshaw Maritime Investments S.A. - 1,063,079
(b)	Percent of class: 1. Konstantinos Konstantakopoulos - 4.9% 2. Longshaw Maritime Investments S.A. - 4.9%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 1. Konstantinos Konstantakopoulos - 1,063,079 2. Longshaw Maritime Investments S.A. - 1,063,079
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 1. Konstantinos Konstantakopoulos - 1,063,079 2. Longshaw Maritime Investments S.A. - 1,063,079
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Konstantakopoulos Konstantinos

Signature:	/s/ Konstantinos Konstantakopoulos
Name/Title:	Konstantinos Konstantakopoulos
Date:	09/21/2026

Longshaw Maritime Investments S.A.

Signature:	/s/ Konstantinos Konstantakopoulos
Name/Title:	Konstantinos Konstantakopoulos
Date:	09/21/2026