Neptune Insurance Holdings Inc.

Unless the context requires otherwise, the words “we,” “us,” “our,” the “Company,” and “Neptune” refer to

Neptune Insurance Holdings Inc. and its subsidiaries, taken as a whole, “Neptune Holdings” refers only to Neptune

Insurance Holdings Inc., and “Neptune Flood” refers only to Neptune Flood Incorporated. For purposes of this

prospectus, unless the context otherwise requires, the term “stockholders” shall refer to the holders of our Class A

common stock and Class B common stock.

We have not, and the selling stockholders and the underwriters have not, authorized anyone to provide you with

additional information or information that is different from or to make any representations other than those

contained in this prospectus or in any free-writing prospectus prepared by or on behalf of us to which we may have

referred you in connection with this offering. We, the selling stockholders and the underwriters, take no

responsibility for, and can provide no assurances as to the reliability of, any other information that others may give

you. This prospectus is an offer to sell only the shares offered hereby, but only under circumstances and in

jurisdictions where offers and sales are permitted. The information contained in this prospectus is accurate only as of

the date of this prospectus, regardless of the time of delivery of this prospectus or of any sale of our common stock.

Our business, financial condition, results of operations, and future growth prospects may have changed since that

date.

Through and including , 2026 (the 25 th day after the date of this prospectus), U.S. federal

securities laws may require all dealers that effect transactions in our common stock, whether or not

participating in this offering, to deliver a prospectus. This is in addition to the dealers’ obligation to deliver a

prospectus when acting as underwriters and with respect to any unsold allotments or subscriptions.

For investors outside the United States, neither we, the selling stockholders nor any of the underwriters have

done anything that would permit this offering or possession or distribution of this prospectus in any jurisdiction

where action for that purpose is required, other than in the United States. Persons who come into possession of this

prospectus in jurisdictions outside the United States are required to inform themselves about and to observe any

restrictions as to this offering and the distribution of this prospectus and any such free-writing prospectus outside the

United States.

ii

TRADEMARKS, TRADE NAMES AND SERVICE MARKS

“Neptune,” “Neptune Flood,” “Triton,” the Neptune stylized design logo, and our other registered or common

law trademarks, trade names, and service marks appearing in this prospectus are our property. Solely for

convenience, our trademarks, trade names, and service marks referred to in this prospectus appear without the®, ™,

and℠ symbols, but those references are not intended to indicate, in any way, that we will not assert, to the fullest

extent under applicable law, our rights to these trademarks and trade names. This prospectus contains additional

trademarks, trade names, and service marks of other companies that are the property of their respective owners.

NON-GAAP FINANCIAL MEASURES AND KEY PERFORMANCE INDICATORS

This prospectus and the documents incorporated by reference herein contain certain financial measures,

including Adjusted EBITDA, Adjusted EBITDA margin, Adjusted net income, Adjusted EBITDA (basic and

diluted) per share, and Adjusted earnings (basic and diluted) per share, that are not required by, or prepared in

accordance with, U.S. generally accepted accounting principles. We refer to these measures as “non-GAAP”

financial measures. See “Management’s Discussion and Analysis of Financial Condition and Results of

Operations — Non-GAAP Financial Measures” in our Annual Report on Form 10-K for the year ended December

31, 2025 (the “Annual Report”) and our Quarterly Report on Form 10-Q for the quarter ended March 31, 2026 (the

“Q1 Quarterly Report”), respectively, each incorporated by reference herein, for our definitions of these non-GAAP

measures, information about how and why we use these non-GAAP measures and a reconciliation of each of these

non-GAAP measures to its most directly comparable financial measure calculated in accordance with GAAP.

This prospectus and the documents incorporated by reference herein also include certain key performance

indicators, including revenue per employee, Adjusted EBITDA per employee, premium in force, policies in force,

policy retention rate, premium retention rate, revenue retention rate, organic revenue, organic revenue growth, and

written premium, that Neptune’s management regularly reviews in managing its business to evaluate its business and

operations, guide decision-making, measure progress and understand growth and retention, and ultimately help drive

profitability. Organic revenue and organic revenue growth are common non-GAAP financial measures reported by

others in the insurance industry. We use “organic revenue” and “organic revenue growth” in this prospectus to

facilitate investors’ understanding of our operating performance and comparison with our peers. However, as of the

date of this prospectus and for the relevant periods presented or incorporated by reference herein, we have not

completed any relevant acquisitions or divestitures, therefore our organic revenue and organic revenue growth

reflect our total revenue and total revenue growth, respectively, as determined in accordance with GAAP. For

definitions of these key performance indicators, see “Management’s Discussion and Analysis of Financial Condition

and Results of Operations — Key Performance Indicators” in our Annual Report and our Q1 Quarterly Report,

respectively, each incorporated by reference herein.