# EDGAR Filing Document

**Accession Number:** 0001953130
**File Stem:** 0001140361-26-012319
**Filing Date:** 2026-3
**Character Count:** 7760
**Document Hash:** 80d033e2c21d367f08986bc6843ffa7a
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001140361-26-012319.hdr.sgml**: 20260331

**ACCESSION NUMBER**: 0001140361-26-012319

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260331

**DATE AS OF CHANGE**: 20260331

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Seanergy Maritime Holdings Corp.
- **CENTRAL INDEX KEY:** 0001448397
- **STANDARD INDUSTRIAL CLASSIFICATION:** DEEP SEA FOREIGN TRANSPORTATION OF FREIGHT [4412]
- **ORGANIZATION NAME:** 01 Energy & Transportation
- **EIN:** 000000000
- **STATE OF INCORPORATION:** 1T
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-84905
- **FILM NUMBER:** 26821678

**BUSINESS ADDRESS:**
- **ADDRESS IS A NON US LOCATION:** YES
- **STREET 1:** 154 VOULIAGMENIS AVENUE
- **STREET 2:** GLYFADA
- **CITY:** ATHENS
- **PROVINCE COUNTRY:** J3
- **BUSINESS PHONE:** 30 210 8913507

**MAIL ADDRESS:**
- **ADDRESS IS A NON US LOCATION:** YES
- **STREET 1:** 154 VOULIAGMENIS AVENUE
- **STREET 2:** GLYFADA
- **CITY:** ATHENS
- **PROVINCE COUNTRY:** J3

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** seanergy maritime holdings corp.
- **DATE OF NAME CHANGE:** 20081021
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Tsantanis Stamatios
- **CENTRAL INDEX KEY:** 0001953130

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**MAIL ADDRESS:**
- **ADDRESS IS A NON US LOCATION:** YES
- **STREET 1:** 154 VOULIAGMENIS AVENUE
- **CITY:** GLYFADA
- **PROVINCE COUNTRY:** J3
- **ZIP:** 16674

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

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 3)**

**Seanergy Maritime Holdings Corp.**

*(Name of Issuer)*

**Common Stock, par value $0.0001 per share**

*(Title of Class of Securities)*

**—**

*(CUSIP Number)*

**Stamatios Tsantanis**<br>154 Vouliagmenis Avenue,<br>Glyfada J3 166 74<br>30 213 01 81 507

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**03/06/2026**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Tsantanis Stamatios** | Name of reporting person<br>**Tsantanis Stamatios** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**J3** | Citizenship or place of organization<br>**J3** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**2084403.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**2084403.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**2084403.00** | Aggregate amount beneficially owned by each reporting person<br>**2084403.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**9.62%** | Percent of class represented by amount in Row (11)<br>**9.62%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock, par value $0.0001 per share

**(b) Name of Issuer:**
Seanergy Maritime Holdings Corp.

**(c) Address of Issuer's Principal Executive Offices:**
154 Vouliagmenis Avenue, Glyfada, J3, 166 74

Explanatory Note: This Amendment No. 3 (this "Amendment No. 3") amends and supplements the Schedule 13D filed with the U.S. Securities and Exchange Commission (the "Commission") on March 31, 2023, as amended and supplemented by Amendment No. 1 to Schedule 13D filed with the Commission on December 28, 2023 and Amendment No. 2 to Schedule 13D filed with the Commission on February 28, 2025 ("Amendment No. 2", and as further amended and supplemented by this Amendment No. 3, the "Schedule 13D") by Stamatios Tsantanis (the "Reporting Person") to reflect an increase in the beneficial ownership by the Reporting Person of shares of common stock (the "Common Stock") of Seanergy Maritime Holdings Corp., a Marshall Islands corporation (the "Issuer").

Capitalized terms used herein but not otherwise defined shall have the meaning set forth in Amendment No. 2. Unless indicated otherwise, all items left blank remain unchanged, and any items which are amended below are deemed to amend and update the existing items in Amendment No. 2.

**Item 5. Interest in Securities of the Issuer**

**(a)**
Aggregate number and percentage of class beneficially owned: 2,084,403 shares, or approximately 9.62% of the class, based on 21,668,198 shares of Common Stock outstanding as of March 27, 2026, based on information received from the Issuer.

**(b)**
The Reporting Person has sole voting and investment power with respect to the Common Stock.

**(c)**
On July 18, 2025, 50 call options held by the Reporting Person to purchase 5,000 shares of Common Stock with an average exercise price of $8.00 expired unexercised.

On October 17, 2025, the Reporting Person exercised 50 call options to purchase 5,000 shares of Common Stock with an exercise price of $8.00 per share.

On October 23, 2025, the Reporting Person sold 1,000 shares of Common Stock at an average price of $8.22 per share.

The information set forth in Item 3 is incorporated herein by reference.

Except as described herein, no transactions in the Common Stock have been effected by the Reporting Person during the past 60 days.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

As described herein, the Reporting Person, in his capacity as an executive officer of the Issuer, has been, and is expected in the future to be, granted shares of Common Stock in accordance with the Issuer's 2011 Equity Incentive Plan, as amended. On March 12, 2025, 196,000 shares of Common Stock were issued and on March 6, 2026, 198,000 shares of Common Stock were issued. These shares of Common Stock are subject to vesting provisions, as follows: 78,400 shares of Common Stock will vest on September 14, 2026, 39,600 shares of Common Stock will vest on September 7, 2026, 59,400 shares of Common Stock will vest on March 8, 2027 and 79,200 shares of Common Stock will vest on September 8, 2027.

Except as set forth in this Amendment No. 3, there are no material changes to this Item 6 from Amendment No. 2.

### 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.

**Reporting Person:** Tsantanis Stamatios

**Signature:** /s/ Stamatios Tsantanis

**Name/Title:** Stamatios Tsantanis

**Date:** 03/31/2026