SEC Form 424B3 filed by Heidmar Maritime Holdings Corp.

Filed Pursuant to Rule 424(b)(3)

Registration No. 333-287869

Prospectus Supplement No. 4

(To Prospectus Dated June 20, 2025)

Heidmar Maritime Holdings Corp.

Up to 11,080,332 Common Shares

This prospectus supplement is being filed to update and supplement the information contained in the prospectus dated June 20, 2025 (as supplemented to date, the “Prospectus”) with the information contained in our report on Form 6-K, filed with the Securities and Exchange Commission on November 6, 2025.

The Prospectus relates to the resale from time to time of up to 11,080,332 common shares, par value US$0.001, per share (“Common Shares”) of Heidmar Maritime Holdings Corp., incorporated under the laws of the Marshall Islands, by B. Riley Principal Capital II, LLC, a Delaware limited liability company.

This prospectus supplement updates and supplements the information in the Prospectus and is not complete without, and may not be delivered or utilized except in combination with, the Prospectus, including any amendments or supplements thereto. This prospectus supplement should be read in conjunction with the Prospectus and if there is any inconsistency between the information in the Prospectus and this prospectus supplement, you should rely on the information in this prospectus supplement.

Our Common Shares are currently listed on The Nasdaq Capital Market under the symbol “HMR.” On November 5, 2025, the last reported sales price of our Common Shares was US$1.30 per share.

Investing in our securities involves a high degree of risk. You should carefully review the risks and uncertainties described in the section titled “Risk Factors” beginning on page 14 of the Prospectus, and under similar headings in any amendments or supplements to the Prospectus.

None of the U.S. Securities and Exchange Commission or any state securities commission has approved or disapproved of the securities or determined if this prospectus supplement or the Prospectus is accurate or adequate. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is November 6, 2025.

Third Quarter 2025 Highlights

in non-cash stock-based compensation.

Adjusted net income from continuing operations is not a measurement recognized under U.S. GAAP (GAAP) and should not be used in isolation or as a substitute for Heidmar’s financial results presented in accordance with GAAP. See “Non-GAAP Financial Measures” later in this prospectus suppleent for the definitions and reconciliation of this measurement to the most directly comparable financial measure calculated and presented in accordance with U.S. GAAP.

THIRD QUARTER 2025 RESULTS COMPARED TO THIRD QUARTER 2024

NINE-MONTH 2025 RESULTS COMPARED TO NINE MONTHS 2024

Total revenues, earned from commissions, management fees and voyage and time charter hire, were $30.8 million for the nine months ended September 30, 2025, up $7.2 million from $23.6 million in the same period of 2024. This growth was primarily due to the increased number of vessels that commenced short-term spot and time charter voyages mostly during the third quarter of 2025 and due to the PSV ACE Supplier, which commenced its charter operations in April 2025. Net loss from continuing operations attributable to shareholders was $4.8 million or $0.08 per share. General and Administration expenses were $13.5 million for the nine months ended September 30, 2025 compared to $9.6 million for the nine months ended September 30, 2024. The increase of $3.9 million is mainly attributable to the costs incurred when the Company listed on the Nasdaq, amortization of the stock-based compensation and the one-off bonus awarded to certain executives.

Key quarterly highlights:

HEIDMAR MARITIME HOLDINGS CORP. FINANCIAL TABLES

Explanatory Note

On February 20, 2025, the common shares of Heidmar Maritime Holdings Corp. (the “Company”) commenced trading on the Nasdaq Capital Market, or Nasdaq, under the symbol “HMR” through a business combination transaction involving Heidmar Inc. (“HMI”) and MGO Global Inc. (“MGO”), a Nasdaq-listed company. The Company and HMI are entities under common control. Pursuant to U.S. generally accepted accounting principles (“U.S. GAAP”), this transaction is accounted for as a business acquisition, with Heidmar Inc. being the accounting acquirer and MGO the acquired entity.

Accordingly, the historical interim financial information of Heidmar Inc. has been carried forward as the historical interim financial information of the Company. The interim financial information for the three-month and nine-month periods ended September 30, 2025, includes the results of operations and financial position of Heidmar Maritime Holdings Corp. and its subsidiaries, Heidmar Inc. and MGO.

Comparative interim financial information for the three-month and nine-month periods ended September 30, 2024, reflects only the historical financial results of Heidmar Inc., the accounting acquirer. The results of MGO for the comparative period are not presented within the comparative financial information, as MGO is accounted for as the acquired entity and its historical interim financial information does not constitute the predecessor interim financial information of the Company. The Company consolidates MGO from the date of acquisition forward.

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(in U.S. dollars)

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEET DATA

(in U.S. dollars)

OTHER FINANCIAL DATA (unaudited)

Nine months ended September 30,

NON-GAAP FINANCIAL MEASURES

Reconciliation of Net Income/(loss) from continuing operations to Adjusted EBITDA

(in U.S. Dollars) (unaudited)

Earnings Before Interest, Taxes, Depreciation and Amortization ("EBITDA") represent net income/ (loss) from continuing operations before interest and finance (income)/ costs, net, depreciation and amortization and income taxes, if any, during a period. EBITDA is not a recognized measurement under U.S. GAAP. Adjusted EBITDA represents EBITDA further adjusted to exclude stock-based compensation and the non-cash expense relating to the fair value of the earnout shares, which the Company believes are not indicative of the ongoing performance of its core operations. We present EBITDA and Adjusted EBITDA as we believe that these measures are useful to investors as a widely used means of evaluating operating profitability. Management also uses these non-GAAP financial measures in making financial, operating and planning decisions and in evaluating the Company’s performance. EBITDA and Adjusted EBITDA as presented here may not be comparable to similarly titled measures presented by other companies. These non-GAAP measures should not be considered in isolation from, as a substitute for, or superior to, financial measures prepared in accordance with U.S. GAAP.

Reconciliation of Net income/(loss) from continuing operations to Adjusted Net Income from continuing operations

(in U.S. Dollars) (unaudited)

Heidmar considers Adjusted net income from continuing operations to represent net income/(loss) before certain non-cash items, including the loss on the fair value of the earnout shares and amortization of stock-based compensation. We have included adjustments for these items because we believe they assist our management and investors by increasing the comparability of the Company's fundamental performance from period to period by excluding the potentially disparate effects these items may have from period-to-period. Adjusted net income from continuing operations per share attributable to shareholders equals Adjusted net income from continuing operations per share attributable to shareholders divided by the weighted average number of shares outstanding during the period. Adjusted net income from continuing operations does not represent and should not be considered as an alternative to net income/(loss) from continuing operations, as determined by GAAP. The Company's definition of Adjusted net income from continuing operations may not be the same as that used by other companies in shipping or other industries. Adjusted net income from continuing operations is not adjusted for all non-cash income and expense items that are reflected in our statement of cash flows.