Neptune Insurance Holdings Inc.

This proxy statement (the “Proxy Statement”) is furnished in connection with the solicitation by the board of directors (the “Board”) of Neptune Insurance Holdings Inc. of proxies from the holders of our Class A common stock, par value $0.00001 per share (the “Class A Common Stock”), and our Class B common stock, par value $0.00001 per share (the “Class B Common Stock,” and together with the Class A Common Stock, the “Common Stock”), for use at the 2026 Annual Meeting of Stockholders of the Company (the “Annual Meeting”) to be held on Thursday, May 28, 2026, at 11:00 a.m. Eastern Time, virtually at https://register.proxypush.com/NP, and at any and all adjournments or postponements thereof, for the purposes set forth in the accompanying Notice of Annual Meeting of Stockholders.

Unless otherwise indicated or unless the context otherwise requires, all references in this Proxy Statement to the “Company,” “Neptune,” “we,” “us,” “our” and similar expressions are references to Neptune Insurance Holdings Inc. and, unless otherwise stated or the context otherwise requires, all of its subsidiaries, including Neptune Flood Incorporated (“Neptune Flood”).

The Company’s Annual Report to Stockholders, which includes the Company’s Form 10-K for the year ended December 31, 2025 (the “Form 10-K”) and other financial information (the “Annual Report”), is included with this Proxy Statement for informational purposes and not as a means of soliciting your proxy. We will furnish any exhibit to our Form 10-K at no charge to any stockholder who provides a written request to the Company’s Secretary at the address above. You can also access our filings with the Securities and Exchange Commission (“SEC”), including our annual reports and all amendments thereto, atwww.sec.gov. On or about April 17, 2026, we expect to mail to our stockholders a Notice of Internet Availability of Proxy Materials containing instructions on how to access the proxy materials online and submit a proxy and how to request email or paper copies if desired.

This summary highlights information contained elsewhere in this Proxy Statement. This summary does not contain all the information that you should consider, and you should read the entire Proxy Statement carefully before voting.