Merlin, Inc.

As filed with the U.S. Securities and Exchange Commission on May 6, 2026

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORMS-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

MERLIN, INC.

(Exact name of registrant as specified in its charter)

100 Causeway, Floor 23

Boston, MA 02114

(617) 226-9968

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Ryan Carrithers

Chief Financial Officer

100 Causeway, Floor 23

Boston, MA 02114

(617) 226-9968

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Stephen W. Ranere Nick S. Dhesi John J. Slater Latham & Watkins LLP 200 Clarendon Street Boston, MA 02116 (617) 948-6000

Approximate date of commencement of proposed sale to the public: From time to time after this registration statement becomes effective.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box:☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering:☐

If this Form is apost-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering:☐

If this Form is apost-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering:☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, anon-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act:

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act:☐

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act or until this registration statement shall become effective on such date as the SEC, acting pursuant to said Section 8(a), may determine.

The information in this preliminary prospectus is not complete and may be changed. These securities may not be sold until the registration statement filed with the U.S. Securities and Exchange Commission is effective. The preliminary prospectus is not an offer to sell these securities and does not constitute the solicitation of offers to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED MAY 6, 2026

MERLIN, INC.

Secondary Offering of

13,336,000 SHARES OF COMMON STOCK

This prospectus relates to the offer and resale, from time to time, by the selling stockholder named in this prospectus, (including its successors or permitted assigns) (the “Selling Stockholder”) of up to 13,336,000 shares of common stock, par value $0.0001 per share (the “Common Stock”), of Merlin, Inc. (“us,” “we,” “New Merlin,” or the “Company”) consisting of:

(i) 8,000,000 shares of Common Stock (the “PIPE Shares”) held by the Selling Stockholder; and

(ii) up to 5,336,000 shares of Common Stock (the “Warrant Shares”) issuable upon exercise of a warrant to purchase such number of shares (the “PIPE Warrant”) held by the Selling Stockholder, assuming, solely for this purpose, an exercise price of $5.00 per share, subject to adjustment (such securities described in clauses (i) through (ii) collectively, the “Resale Shares”).

The PIPE Shares and the PIPE Warrant were issued to the Selling Stockholder pursuant to that certain Securities Purchase Agreement, dated April 29, 2026 (the “SPA”), by and between the Company and the Selling Stockholder (the “PIPE”).

We are registering resale of the Resale Shares to satisfy certain registration rights we have granted to the Selling Stockholder pursuant to that certain amended and restated registration rights agreement, dated April 29, 2026, by and between the Company and the Selling Stockholder (the “Registration Rights Agreement”). The Selling Stockholder may offer all or part of the Resale Shares for resale from time to time through public or private transactions, at either prevailing market prices or at privately negotiated prices. The Resale Shares are being registered to permit the Selling Stockholder to sell Resale Shares from time to time, in amounts, at prices and on terms determined at the time of offering. The Selling Stockholder may sell the Resale Shares through ordinary brokerage transactions, in underwritten offerings, directly to market makers of our securities or through any other means described in the section entitled “Plan of Distribution” herein. In connection with any sales of Resale Shares offered hereunder, the Selling Stockholder, any underwriters, agents, brokers or dealers participating in such sales may be deemed to be “underwriters” within the meaning of the Securities Act, or the Exchange Act. We are registering the Resale Shares for resale by the Selling Stockholder, or their successors or permitted assigns, selling our Common Stock or interests received in our Common Stock received after the date of this prospectus from the Selling Stockholder as a gift, pledge, partnership distribution or other transfer.

The shares of Common Stock being registered for resale were acquired or may be acquired by the Selling Stockholder for prices considerably below the current market price of the shares of Common Stock. Accordingly, the Selling Stockholder may have an incentive to sell because they have purchased or have the right to purchase the Resale Shares at effective prices significantly lower than our public investors or the current trading price of the Common Stock and may profit significantly even under circumstances in which our other stockholders would experience losses in connection with their investment. For additional information, see “Risk Factors — Sales of a substantial number of our securities in the public market by the Selling Stockholder and/or by our existing securityholders could cause the price of our shares of Common Stock to fall.”

The shares of Common Stock being offered for resale by the Selling Stockholder pursuant to this prospectus represent approximately 13.5% of our total issued and outstanding Common Stock (assuming and after giving effect to the issuance of the Warrant Shares). Given the substantial number of Resale Shares being registered for potential resale by the Selling Stockholder pursuant to the registration statement of which this prospectus forms a part, the sale of such Resale Shares by the Selling Stockholder, or the perception in the market that the Selling Stockholder may sell or intends to sell all or a significant portion of such Resale Shares, could increase the volatility of the market price of our Common Stock or result in a significant decline in the public trading price of our Common Stock.

We will not receive any proceeds from the sale of the Resale Shares by the Selling Stockholder. We will receive the proceeds upon exercise of the PIPE Warrant to the extent such PIPE Warrant is exercised for cash. Assuming the exercise of the PIPE Warrant for cash, we would receive aggregate proceeds of approximately $26.7 million. However, we will only receive such proceeds if the PIPE Warrant holder fully exercises their PIPE Warrant for cash. The current exercise price of

the PIPE Warrant is $6.67 per share. We believe that the likelihood that the holder determines to exercise their PIPE Warrant, and therefore the amount of cash proceeds that we would receive, is dependent upon the market price of our Common Stock. If the market price of our Common Stock is less than the exercise price of the PIPE Warrant (on a per share basis), we believe that the holder will be very unlikely to exercise their PIPE Warrant, and accordingly, we will not receive any such proceeds. There is no assurance that the PIPE Warrant will be or will remain “in the money” prior to their expiration or that the holder will exercise their PIPE Warrant.

We will bear all costs, expenses, and fees in connection with the registration of the Resale Shares. The Selling Stockholder will bear all commissions and discounts, if any, attributable to its sales of the shares of Common Stock.

Our shares of Common Stock are listed on the Nasdaq Stock Market LLC (“Nasdaq”) under the symbol “MRLN”. On May 5, 2026, the closing price of our Common Stock was $8.97 per share.

We are an “emerging growth company” and a “smaller reporting company” under the federal securities laws and will be subject to reduced disclosure and public reporting requirements. See “Summary — Implications of Being an Emerging Growth Company and a Smaller Reporting Company.”

Investing in shares of our securities involves risks that are described in the “Risk Factors” section beginning on page 9 of this prospectus.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued under this prospectus or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is , 2026.