# EDGAR Filing Document

**Accession Number:** 0001720161
**File Stem:** 0001140361-25-024977
**Filing Date:** 2025-7
**Character Count:** 20366
**Document Hash:** 4ad8a3300e2fe1f5ad8ac4bf8603d339
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001140361-25-024977.hdr.sgml**: 20250707

**ACCESSION NUMBER**: 0001140361-25-024977

**CONFORMED SUBMISSION TYPE**: 6-K

**PUBLIC DOCUMENT COUNT**: 4

**CONFORMED PERIOD OF REPORT**: 20250707

**FILED AS OF DATE**: 20250707

**DATE AS OF CHANGE**: 20250707

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Castor Maritime Inc.
- **CENTRAL INDEX KEY:** 0001720161
- **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:** 6-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-38802
- **FILM NUMBER:** 251107064

**BUSINESS ADDRESS:**
- **STREET 1:** CHRISTODOULOU CHATZIPAVLOU 223
- **STREET 2:** HAWAII ROYAL GARDENS, APART. 16
- **CITY:** LIMASSOL
- **STATE:** G4
- **ZIP:** 3036
- **BUSINESS PHONE:** 357 25357767

**MAIL ADDRESS:**
- **STREET 1:** CHRISTODOULOU CHATZIPAVLOU 223
- **STREET 2:** HAWAII ROYAL GARDENS, APART. 16
- **CITY:** LIMASSOL
- **STATE:** G4
- **ZIP:** 3036

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### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549

### FORM 6-K

#### REPORT OF FOREIGN PRIVATE ISSUER

#### PURSUANT TO RULE 13A-16 OR 15D-16 OF

#### THE SECURITIES EXCHANGE ACT OF 1934

#### For the month of July 2025

#### Commission File Number: 001-38802

## CASTOR MARITIME INC.

#### (Translation of registrant's name into English)

#### 223 Christodoulou Chatzipavlou Street, Hawaii Royal Gardens, 3036 Limassol, Cyprus

#### (Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒ Form 40-F ☐

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#### INFORMATION CONTAINED IN THIS FORM 6-K REPORT

Castor Maritime Inc.'s subsidiary, MPCC CSI LTD., a company affiliated with MPC Capital AG, has acquired 3.44% shares in MPC Container Ships ASA ("MPCC"), resulting in MPC Capital AG and its affiliated entities, collectively increasing their holding of total shares and voting rights in MPCC from approximately 16.68% to 20.12%, or 89,260,056 shares. MPC Capital AG is the founding shareholder of MPCC.

Attached to this report on Form 6-K as [Exhibit 99.1](ef20051644_ex99-1.htm) is a copy of the notification of major holdings.

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#### SIGNATURES

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, thereunto duly authorized.

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| | | |
|:---|:---|:---|
|  | **CASTOR MARITIME INC.** | **CASTOR MARITIME INC.** |
| Dated: July 7, 2025 |  |  |
|  | By: | /s/ Petros Panagiotidis |
|  |  | Petros Panagiotidis |
|  |  | Chairman, Chief Executive Officer and Chief Financial Officer |

---

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## Exhibit 99.1

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#### Exhibit 99.1<br>

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| | |
|:---|:---|
| ![](image00002.jpg) | Nasdaq Date: July 2025<br> ESMA/2015/1597 |

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#### <br>

#### Form for notification of major holdings

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| | |
|:---|:---|
| **NOTIFICATION OF MAJOR HOLDINGS** (to be sent to the relevant issuer <u>and</u> to the competent authority)<sup>i</sup> | **NOTIFICATION OF MAJOR HOLDINGS** (to be sent to the relevant issuer <u>and</u> to the competent authority)<sup>i</sup> |
| **1. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached**<sup>ii</sup>**:**<br>MPC Container Ships ASA (ISIN: NO0010791353) | **1. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached**<sup>ii</sup>**:**<br>MPC Container Ships ASA (ISIN: NO0010791353) |
| **2. Reason for the notification** (please tick the appropriate box or boxes):<br>☒ An acquisition or disposal of voting rights<br> ☐ An acquisition or disposal of financial instruments<br> ☐ An event changing the breakdown of voting rights<br> ☐ Other (please specify)<sup>iii</sup>: | **2. Reason for the notification** (please tick the appropriate box or boxes):<br>☒ An acquisition or disposal of voting rights<br> ☐ An acquisition or disposal of financial instruments<br> ☐ An event changing the breakdown of voting rights<br> ☐ Other (please specify)<sup>iii</sup>: |
| 3. Details of person subject to the notification obligation: | 3. Details of person subject to the notification obligation: |
| Name:<br>Thalassa Investment Co. S.A<br> Castor Maritime Inc.<br> MPCC CSI LTD.<br> Thalvora Holdings GmbH<br> MPC Capital AG<br> MPC Capital Beteiligungsgesellschaft mbH & Co. KG<br> MPC CSI GmbH<br>| <br>Liberia<br> Marshall Islands<br> Cyprus<br> Germany<br> Germany<br> Germany<br> Germany<br>|
| **4. Full name of shareholder(s)** (if different from 3.)<sup>v</sup>:<br> MPCC CSI LTD., Cyprus, being the acquiring entity. | **4. Full name of shareholder(s)** (if different from 3.)<sup>v</sup>:<br> MPCC CSI LTD., Cyprus, being the acquiring entity. |
| **5. Date on which the threshold was crossed or reached**<sup>vi</sup>**:**<br> 4<sup>th</sup> July 2025 | **5. Date on which the threshold was crossed or reached**<sup>vi</sup>**:**<br> 4<sup>th</sup> July 2025 |

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| | | | | |
|:---|:---|:---|:---|:---|
| 6. Total positions of person(s) subject to the notification obligation: | 6. Total positions of person(s) subject to the notification obligation: | 6. Total positions of person(s) subject to the notification obligation: | 6. Total positions of person(s) subject to the notification obligation: | 6. Total positions of person(s) subject to the notification obligation: |
|  | % of voting rights<br> attached to shares<br> (total of 7.A) | % of voting rights<br> through financial<br> instruments<br> (total of 7.B.1 + 7.B.2) | Total of both in %<br> (7.A + 7.B) | Total number of<br> voting rights of<br> issuer<sup>vii</sup> |
| Resulting situation on the date on which threshold was crossed or reached | 20.12% | - | 20.12% | 443700279 |
| Position prior to the notification (if applicable) | 19.99% | - | 19.99% |  |

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![](image00003.jpg)

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| | | | | |
|:---|:---|:---|:---|:---|
| **7. Notified details of the resulting situation on the date on which the threshold was crossed or reached**<sup>viii</sup>**:** | **7. Notified details of the resulting situation on the date on which the threshold was crossed or reached**<sup>viii</sup>**:** | **7. Notified details of the resulting situation on the date on which the threshold was crossed or reached**<sup>viii</sup>**:** | **7. Notified details of the resulting situation on the date on which the threshold was crossed or reached**<sup>viii</sup>**:** | **7. Notified details of the resulting situation on the date on which the threshold was crossed or reached**<sup>viii</sup>**:** |
| **A: Voting rights attached to shares** | **A: Voting rights attached to shares** | **A: Voting rights attached to shares** | **A: Voting rights attached to shares** | **A: Voting rights attached to shares** |
| **Class/type of**<br> **shares**<br> ISIN code (if possible) | &nbsp;&nbsp;&nbsp; **Number of voting rights**<sup>ix</sup> | &nbsp;&nbsp;&nbsp; **Number of voting rights**<sup>ix</sup> | &nbsp;&nbsp;&nbsp; **% of voting rights** | &nbsp;&nbsp;&nbsp; **% of voting rights** |
| **Class/type of**<br> **shares**<br> ISIN code (if possible) | **Direct**<br> (Art 9 of Directive<br> 2004/109/EC) | **Indirect**<br> (Art 10 of Directive<br> 2004/109/EC) | **Direct**<br> (Art 9 of Directive<br> 2004/109/EC) | **Indirect**<br> (Art 10 of Directive<br> 2004/109/EC) |
| Equity<br> (NO0010791353) | 15265079 | 73994977 | 3.44% | 16.68% |
| **SUBTOTAL A** | 89260056 | 89260056 | 20.12% | 20.12% |

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| | | | | |
|:---|:---|:---|:---|:---|
| **B 1: Financial Instruments according to Art. 13(1)(a) of Directive 2004/109/EC** | **B 1: Financial Instruments according to Art. 13(1)(a) of Directive 2004/109/EC** | **B 1: Financial Instruments according to Art. 13(1)(a) of Directive 2004/109/EC** | **B 1: Financial Instruments according to Art. 13(1)(a) of Directive 2004/109/EC** | **B 1: Financial Instruments according to Art. 13(1)(a) of Directive 2004/109/EC** |
| **Type of financial**<br> **instrument** | **Expiration**<br> **date**<sup>x</sup> | **Exercise/**<br> **Conversion** <br> **Period**<sup>xi</sup> | **Number of voting rights**<br> **that may be acquired if**<br> **the instrument is**<br> **exercised/ converted.** | **% of voting rights** |
| n.a. |  |  |  |  |
|  |  | **SUBTOTAL B.1** |  |  |

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| | | | | | |
|:---|:---|:---|:---|:---|:---|
| **B 2: Financial Instruments with similar economic effect according to Art. 13(1)(b) of Directive 2004/109/EC** | **B 2: Financial Instruments with similar economic effect according to Art. 13(1)(b) of Directive 2004/109/EC** | **B 2: Financial Instruments with similar economic effect according to Art. 13(1)(b) of Directive 2004/109/EC** | **B 2: Financial Instruments with similar economic effect according to Art. 13(1)(b) of Directive 2004/109/EC** | **B 2: Financial Instruments with similar economic effect according to Art. 13(1)(b) of Directive 2004/109/EC** | **B 2: Financial Instruments with similar economic effect according to Art. 13(1)(b) of Directive 2004/109/EC** |
| **Type of financial**<br> **instrument** | **Expiration**<br> **date**<sup>x</sup> | **Exercise/**<br> **Conversion**<br> **Period** <sup>xi</sup> | **Physical or cash**<br> **settlement**<sup>xii</sup> | **Number of**<br> **voting rights** | **% of voting rights** |
| n.a. |  |  |  |  |  |
|  |  |  | **SUBTOTAL B.2** |  |  |

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![](image00003.jpg)

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| | | | |
|:---|:---|:---|:---|
| **8. Information in relation to the person subject to the notification obligation** (please tick the applicable box)**:**<br>**☐ Person subject to the notification obligation is not controlled by any natural person or legal entity and does not control any other undertaking(s) holding directly or indirectly an interest in the (underlying) issuer.**<sup>xiii</sup><br>**☒ <u>Full</u> chain of controlled undertakings through which the voting rights and/or the**<br> **financial instruments are effectively held starting with the ultimate controlling natural person or legal entity**<sup>xiv</sup>**:** | **8. Information in relation to the person subject to the notification obligation** (please tick the applicable box)**:**<br>**☐ Person subject to the notification obligation is not controlled by any natural person or legal entity and does not control any other undertaking(s) holding directly or indirectly an interest in the (underlying) issuer.**<sup>xiii</sup><br>**☒ <u>Full</u> chain of controlled undertakings through which the voting rights and/or the**<br> **financial instruments are effectively held starting with the ultimate controlling natural person or legal entity**<sup>xiv</sup>**:** | **8. Information in relation to the person subject to the notification obligation** (please tick the applicable box)**:**<br>**☐ Person subject to the notification obligation is not controlled by any natural person or legal entity and does not control any other undertaking(s) holding directly or indirectly an interest in the (underlying) issuer.**<sup>xiii</sup><br>**☒ <u>Full</u> chain of controlled undertakings through which the voting rights and/or the**<br> **financial instruments are effectively held starting with the ultimate controlling natural person or legal entity**<sup>xiv</sup>**:** | **8. Information in relation to the person subject to the notification obligation** (please tick the applicable box)**:**<br>**☐ Person subject to the notification obligation is not controlled by any natural person or legal entity and does not control any other undertaking(s) holding directly or indirectly an interest in the (underlying) issuer.**<sup>xiii</sup><br>**☒ <u>Full</u> chain of controlled undertakings through which the voting rights and/or the**<br> **financial instruments are effectively held starting with the ultimate controlling natural person or legal entity**<sup>xiv</sup>**:** |
| **Name**<sup>xv</sup> | **% of voting rights if**<br> **it equals or is**<br> **higher than the**<br> **notifiable threshold** | **% of voting rights**<br> **through financial**<br> **instruments if it equals**<br> **or is higher than the**<br> **notifiable threshold** | **Total of both if it**<br> **equals or is higher**<br> **than the notifiable**<br> **threshold** |
| Thalassa Investment Co. S.A. |  |  |  |
| Castor Maritime Inc. |  |  |  |
| MPCC CSI LTD. | 3.44 |  | 3.44 |
| Thalvora Holdings GmbH |  |  |  |
| MPC Capital AG |  |  |  |
| MPC Capital Beteiligungsgesellschaft mbH & Co. KG |  |  |  |
| MPC CSI GmbH<br>| 16.68 |  | 16.68 |
| 9. In case of proxy voting: [*name of the proxy holder*] will cease to hold [% and *number*] voting rights as of [*date*] | 9. In case of proxy voting: [*name of the proxy holder*] will cease to hold [% and *number*] voting rights as of [*date*] | 9. In case of proxy voting: [*name of the proxy holder*] will cease to hold [% and *number*] voting rights as of [*date*] | 9. In case of proxy voting: [*name of the proxy holder*] will cease to hold [% and *number*] voting rights as of [*date*] |
| **10. Additional information**<sup>xvi</sup>**:** | **10. Additional information**<sup>xvi</sup>**:** | **10. Additional information**<sup>xvi</sup>**:** | **10. Additional information**<sup>xvi</sup>**:** |

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Done at Hamburg on 4th of July 2025

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![](image00003.jpg)

#### Notes

*<sup>i</sup> Please note that national forms may vary due to specific national legislation (Article 3(1a) of Directive 2004/109/EC) as for instance the applicable thresholds or information regarding capital holdings.*

*<sup>ii</sup> Full name of the legal entity and further specification of the issuer or underlying issuer, provided it is reliable and accurate (e.g. address, LEI, domestic number identity).*

*<sup>iii</sup> Other reason for the notification could be voluntary notifications, changes of attribution of the nature of the holding (e.g. expiring of financial instruments) or acting in concert.*

*<sup>iv</sup> This should be the full name of (a) the shareholder; (b) the natural person or legal entity acquiring, disposing of or exercising voting rights in the cases provided for in Article 10 (b) to (h) of Directive 2004/109/EC; or (c) the holder of financial instruments referred to in Article 13(1) of Directive 2004/109/EC.*

*As the disclosure of cases of acting in concert may vary due to the specific circumstances (e.g. same or different total positions of the parties, entering or exiting of acting in concert by a single party) the standard form does not provide for a specific method how to notify cases of acting in concert.*

*In relation to the transactions referred to in points (b) to (h) of Article 10 of Directive 2004/109/EC, the following list is provided as indication of the persons who should be mentioned:*

*- in the circumstances foreseen in letter (b) of Article 10 of that Directive, the natural person or legal entity that acquires the voting rights and is entitled to exercise them under the agreement and the natural person or legal entity who is transferring temporarily for consideration the voting rights;*

*- in the circumstances foreseen in letter (c) of Article 10 of that Directive, the natural person or legal entity holding the collateral, provided the person or entity controls the voting rights and declares its intention of exercising them, and natural person or legal entity lodging the collateral under these conditions;*

*- in the circumstances foreseen in letter (d) of Article 10 of that Directive, the natural person or legal entity who has a life interest in shares if that person or entity is entitled to exercise the voting rights attached to the shares and the natural person or legal entity who is disposing of the voting rights when the life interest is created;*

*- in the circumstances foreseen in letter (e) of Article 10 of that Directive, the controlling natural person or legal entity and, provided it has a notification duty at an individual level under Article 9, under letters (a) to (d) of Article 10 of that Directive or under a combination of any of those situations, the controlled undertaking;*

*- in the circumstances foreseen in letter (f) of Article 10 of that Directive, the deposit taker of the shares, if he can exercise the voting rights attached to the shares deposited with him at his discretion, and the depositor of the shares allowing the deposit taker to exercise the voting rights at his discretion;*

*- in the circumstances foreseen in letter (g) of Article 10 of that Directive, the natural person or legal entity that controls the voting rights;*

*- in the circumstances foreseen in letter (h) of Article 10 of that Directive, the proxy holder, if he can exercise the voting rights at his discretion, and the shareholder who has given his proxy to the proxy holder allowing the latter to exercise the voting rights at his discretion (e.g. management companies).*

*<sup>v</sup> Applicable in the cases provided for in Article 10 (b) to (h) of Directive 2004/109/EC. This should be the full name of the shareholder who is the counterparty to the natural person or legal entity referred to in Article 10 of that Directive unless the percentage of voting rights held by the shareholder is lower than the lowest notifiable threshold for the disclosure of voting rights holdings in accordance with national practices (e.g. identification of funds managed by management companies).*

*<sup>vi</sup> The date on which threshold is crossed or reached should be the date on which the acquisition or disposal took place or the other reason triggered the notification obligation. For passive crossings, the date when the corporate event took effect.*

*<sup>vii</sup> The total number of voting rights shall be composed of all the shares, including depository receipts representing shares, to which voting rights are attached even if the exercise thereof is suspended.*

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![](image00003.jpg)

*<sup>viii</sup> If the holding has fallen below the lowest applicable threshold in accordance with national law, please note that it might not be necessary in accordance with national law to disclose the extent of the holding, only that the new holding is below that threshold.*

*<sup>ix</sup> In case of combined holdings of shares with voting rights attached "direct holding" and voting rights "indirect holding", please split the voting rights number and percentage into the direct and indirect columns – if there is no combined holdings, please leave the relevant box blank.*

*<sup>x</sup> Date of maturity/expiration of the financial instrument i.e. the date when right to acquire shares ends.*

*<sup>xi</sup> If the financial instrument has such a period – please specify this period – for example once every 3 months starting from [date].*

*<sup>xii</sup> In case of cash settled instruments the number and percentages of voting rights is to be presented on a delta-adjusted basis (Article 13(1a) of Directive 2004/109/EC).*

*<sup>xiii</sup> If the person subject to the notification obligation is either controlled and/or does control another undertaking then the second option applies.*

*<sup>xiv</sup> The full chain of controlled undertakings starting with the ultimate controlling natural person or legal entity has to be presented also in the cases, in which only on subsidiary level a threshold is crossed or reached and the subsidiary undertaking discloses the notification as only thus the markets get always the full picture of the group holdings. In case of multiple chains through which the voting rights and/or financial instruments are effectively held the chains have to be presented chain by chain leaving a row free between different chains (e.g.: A, B, C, free row, A, B, D, free row, A, E, F etc.).*

*<sup>xv</sup> The names of controlled undertakings through which the voting rights and/or financial instruments are effectively held have to be presented irrespectively whether the controlled undertakings cross or reach the lowest applicable threshold themselves.*

*<sup>xvi</sup> Example: Correction of a previous notification.*

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