[424B5] Fusion Fuel Green PLC Prospectus Supplement (Debt Securities)

Rhea-AI Filing Summary

Fusion Fuel Green PLC (Nasdaq: HTOO) has filed a 424(b)(5) prospectus supplement dated 28 Jul 2025 to expand its at-the-market (ATM) equity program with H.C. Wainwright. The filing registers up to $4.184 million in additional Class A ordinary shares, separate from the $2.064 million already sold since the prior 16 May 2025 supplement.

Under Form F-3 General Instruction I.B.5, issuers with a public float under $75 million may not sell securities exceeding one-third of that float in any 12-month period. Fusion Fuel’s non-affiliate float is $18.744 million (1,721,961 shares) as of 25 Jul 2025, so the new capacity remains within the rule’s limit. If float later exceeds $75 million, the one-third restriction would drop.

The last quoted prices on 25 Jul 2025 were $6.99 for the shares and $0.04 for the warrants, both trading on the Nasdaq Capital Market. While the supplement highlights the speculative nature of an investment in HTOO, it offers the company additional liquidity; conversely, any future share issuance will dilute existing holders.

Positive

• Ability to raise up to $4.184 million in new equity through the ATM provides incremental liquidity without negotiating a separate financing round.
• Shares and warrants remain listed on Nasdaq, preserving access to public capital markets and investor visibility.

Negative

• Potential dilution: additional share issuance could reduce existing shareholders’ percentage ownership and earnings per share.
• Small public float of $18.7 million underscores micro-cap status and higher volatility, keeping the company subject to the Form F-3 one-third limitation.

Insights

Equity Capital Markets Analyst

TL;DR: $4.18 m extra ATM headroom; liquidity boost offsets dilution risk—overall neutral.

This supplement merely enlarges Fusion Fuel's ongoing ATM programme, keeping total 12-month issuance within the one-third public-float cap. The dollar amount—roughly 22% of float—is modest but meaningful for a micro-cap firm, potentially extending runway without committed financing costs. Investors should weigh cash-raising flexibility against immediate dilution pressure, especially given average trading volume constraints.

Renewable Energy Industry Specialist

TL;DR: Capital raise is small relative to sector needs; limited strategic impact.

Hydrogen technology projects are capital-intensive; an additional $4.18 million offers short-term liquidity but is unlikely to materially accelerate large-scale deployments. Because the supplement contains no new project, revenue, or partnership disclosures, the filing’s strategic significance is limited. Nonetheless, maintaining Nasdaq listing and funding optionality supports credibility with future partners.

Filed Pursuant to Rule 424(b)(5)

Registration No. 333-264714

PROSPECTUS SUPPLEMENT

(To Prospectus dated May 13, 2022)

Up to $4,184,136

Class A Ordinary Shares 

FUSION FUEL GREEN PLC

This prospectus supplement amends and supplements the information in the prospectus supplement, dated May 16, 2025 (the “Prior Prospectus Supplement”), and the prospectus, dated May 13, 2022 (the “Prospectus”), of Fusion Fuel Green PLC, an Irish public limited company (“we,” “us,” “our,” or the “Company”), relating to the offer and sale of up to $2,064,262 of Class A ordinary shares with a nominal value of $0.0035 each of the Company (“Class A Ordinary Shares”), pursuant to the At The Market Offering Agreement between the Company and H.C. Wainwright & Co., LLC (“Wainwright”), dated as of May 16, 2025 (the “ATM Agreement”). This prospectus supplement is registering the offer and sale of up to $4,184,136 of our Class A Ordinary Shares, not including the Class A Ordinary Shares previously sold pursuant to the ATM Agreement. This prospectus supplement should be read in conjunction with the Prior Prospectus Supplement, and is qualified by reference thereto, except to the extent that the information herein amends or supersedes the information contained in the Prior Prospectus Supplement. This prospectus supplement is not complete without, and may only be delivered or utilized in connection with, the Prior Prospectus Supplement and any future amendments or supplements thereto.

Our Class A Ordinary Shares and our public warrants are listed on The Nasdaq Capital Market tier of The Nasdaq Stock Market LLC under the symbols “HTOO” and “HTOOW”, respectively. The last reported sale price of the Class A Ordinary Shares and the public warrants on July 25, 2025 was $6.99 per share and $0.04 per warrant, respectively.

As of July 25, 2025, the aggregate market value of our outstanding Class A Ordinary Shares held by non-affiliates was $18,744,406 based upon 1,729,082 outstanding Class A Ordinary Shares, of which 1,721,961 Class A Ordinary Shares were held by non-affiliates, and the last reported sale price of our Class A Ordinary Shares of $10.8855 per share on June 10, 2025. Pursuant to General Instruction I.B.5. of Form F-3, in no event will we sell securities in a public primary offering with a value exceeding one-third of our public float in any 12-month period so long as our public float remains below $75.0 million. In the event that subsequent to the date of this prospectus supplement the aggregate market value of our outstanding Class A Ordinary Shares held by non-affiliates equals or exceeds $75,000,000, such one-third limitation on sales shall not apply to sales subsequently made pursuant to this prospectus supplement.

As of the date of this prospectus supplement, we have offered and sold $2,063,999 of securities pursuant to General Instruction I.B.5 of Form F-3 during the 12-calendar month period that ends on and includes the date hereof, and therefore $4,184,136 is available to be sold pursuant to this prospectus supplement.

Investing in our securities is highly speculative and involves a high degree of risk. See “Risk Factors” beginning on page S-5 of the Prior Prospectus Supplement and as described in or in exhibits to certain of the documents we may incorporate by reference therein, for a discussion of information that should be considered in connection with an investment in our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement, the Prior Prospectus Supplements, or the Prospectus. Any representation to the contrary is a criminal offense.

H.C. Wainwright & Co.

The date of this prospectus supplement is July 28, 2025.

FAQ

How many additional shares can Fusion Fuel (HTOO) sell under this ATM supplement?

The filing registers up to $4,184,136 in Class A ordinary shares.

What is Fusion Fuel’s current public float?

As of 25 Jul 2025, non-affiliate float is $18,744,406, representing 1,721,961 shares.

What restriction limits HTOO’s ATM sales under Form F-3?

While float remains below $75 million, sales in any 12-month period are capped at one-third of that float.

How much has the company already sold through the ATM in the past 12 months?

HTOO has issued $2,063,999 of securities during the 12-month period ending on the supplement date.

At what price did HTOO shares last trade before this filing?

The last reported price on 25 Jul 2025 was $6.99 per share.

Where are HTOO shares and warrants listed?

Both the Class A shares (HTOO) and public warrants (HTOOW) trade on the Nasdaq Capital Market.