UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15 (d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): May 14, 2025

NKGen Biotech, Inc.

(Exact name of registrant as specified in its charter)

3001 Daimler Street

Santa Ana, CA, 92705

(Address of principal executive offices and zip code)

Registrant’s telephone number, including area code: (949) 396-6830

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2 below):

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☒

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 13(a) of the Exchange Act. ☐

Item 1.01. Entry into a Material Definitive Agreement.

CFIC Securities Purchase Agreement

On May 14, 2025, NKGen Biotech, Inc. (the “Company”) entered into a Stock Purchase Agreement (the “Agreement”) with CFIC-2015 NV Family Investments, LLC (the “Purchaser”), pursuant to which the Company agreed to issue and sell, and the Purchaser agreed to purchase, an aggregate of 19,669,552 shares of the Company’s common stock, par value $0.0001 per share (the “Shares”), at a purchase price of $0.1271 per share (the “Share Price”), subject to adjustment, for an aggregate purchase price of $2,500,000.00 (the “Purchase Price”). The Share Price was determined based on the per share purchase price under the Company’s most recent stock purchase agreement with Paul Y. Song, as disclosed in the Company’s Current Report on Form 8-K filed on May 8, 2025, which Purchaser had the right to participate on the same terms thereof.

As of the date of this filing, the Purchaser’s payment of the Purchase Price is pending and, upon receipt of payment of the Purchase Price, the Company will issue the Shares to the Purchaser.

In addition to the Shares, and subject to receipt of the Purchase Price, the Company agreed to issue to the Purchaser a common stock purchase warrant (the “Warrant”) to purchase up to 39,339,103 shares of common stock, exercisable at the Share Price.

The offering and sale of the Shares and the Warrant (collectively, the “Securities”) were made in reliance upon the exemption from registration provided by Section 4(a)(2) of the Securities Act of 1933, as amended (the “Securities Act”), and Rule 506 of Regulation D promulgated thereunder. The Securities have not been registered under the Securities Act and may not be offered or sold absent registration or an applicable exemption from the Securities Act’s registration requirements.

The foregoing description of the Agreement and the Warrant does not purport to be complete and is qualified in its entirety by reference to the full text of the Agreement and the form of Warrant, which are filed as Exhibits 10.1 and 4.1, respectively, to this Current Report on Form 8-K and are incorporated herein by reference.

Item 3.02. Unregistered Sales of Equity Securities.

The information set forth in Item 1.01 of this Current Report on Form 8-K is incorporated herein by reference. The Securities were issued and sold in reliance upon the exemption from registration provided by Section 4(a)(2) of the Securities Act and Rule 506 of Regulation D promulgated thereunder. The Purchaser represented that it is an “accredited investor” as defined in Rule 501(a) under the Securities Act. The Securities have not been registered under the Securities Act or any state securities laws and may not be offered or sold in the United States absent registration or an applicable exemption from registration requirements.

Item 9.01. Financial Statements and Exhibits

(d) Exhibits.

SIGNATURES

Pursuant to the requirements of Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.