NKGen Biotech (NKGN) boosts Alpine note to $26.76M with new $251K loan

Rhea-AI Filing Summary

NKGen Biotech, Inc. entered into a third amendment to its secured promissory note with AlpineBrook Capital GP I Limited on January 30, 2026. The amendment provides an additional $251,000 in loan funding, increasing the note’s principal balance to $26,758,106.

The amendment also clarifies that interest on this new loan tranche, referred to as the Fourth Additional New Loan, begins accruing from January 30, 2026, the funding date. This creates an additional direct financial obligation for NKGen and its subsidiary NKGen Operating Biotech, Inc.

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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): January 30, 2026

NKGen Biotech, Inc.

(Exact name of registrant as specified in its charter)

Delaware		001-40427		86-2191918
(State or other jurisdiction of incorporation)		(Commission File Number)		(IRS Employer Identification No.)

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):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, $0.0001 par value per share		NKGN		OTC Expert Market
Warrants, each whole warrant exercisable for one share of Common Stock at an exercise price of $11.50 per share		NKGNW		OTC Expert Market

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.

On January 30, 2026, NKGen Biotech, Inc. (the “Company”) and NKGen Operating Biotech, Inc., a Delaware corporation (together with the Company, the “Borrowers”), entered into a third amendment (the “Alpine Third Amendment”) to that certain secured promissory note with AlpineBrook Capital GP I Limited, dated January 5, 2026, as amended by that certain amendment to secured promissory note dated January 12, 2026 and that certain amendment no. 2 to secured promissory note (the “Note”).

The Alpine Third Amendment provides an additional $251,000 of funding to the Borrowers (the “Fourth Additional New Loan”). As a result, the principal amount of the Note was increased to $26,758,106. The Alpine Third Amendment also clarifies that interest on the Fourth Additional New Loan accrues from January 30, 2026 (the date on which the Fourth Additional New Loan was funded).

The foregoing description of the Alpine Third Amendment does not purport to be complete and is qualified in its entirety by the terms and conditions of the Alpine Third Amendment, which is filed as Exhibit 10.1 to this Current Report on Form 8-K and incorporated herein by reference.

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

The disclosures set forth in Item 1.01 are incorporated by into this Item 2.03 by reference.

Item 9.01. Financial Statements and Exhibits

(d) Exhibits.

Exhibit No.		Description
10.1		Amendment No. 3 to Secured Promissory Note issued to the AlpineBrook Capital GP I Limited, dated January 30, 2026.
104		Cover Page Interactive Data File (embedded within the Inline XBRL document)

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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.

	NKGEN BIOTECH, INC.
Date: February 5, 2026	/s/ Paul Y. Song
	Name:	Paul Y. Song
	Title:	Chief Executive Officer
		(Principal Executive Officer)

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FAQ

What did NKGen Biotech (NKGN) announce in this 8-K filing?

NKGen Biotech disclosed a third amendment to its secured promissory note with AlpineBrook Capital GP I Limited. The amendment adds a new loan tranche and increases the total principal owed, creating an additional direct financial obligation for the company and its operating subsidiary.

How much additional funding did NKGen Biotech (NKGN) receive under the Alpine Third Amendment?

The Alpine Third Amendment provides NKGen Biotech with an additional $251,000 in funding, called the Fourth Additional New Loan. This amount is added to the existing secured promissory note, increasing NKGen’s overall debt balance under that note with AlpineBrook Capital GP I Limited.

What is the new total principal amount of NKGen Biotech’s secured promissory note?

After the Alpine Third Amendment, the principal amount of NKGen Biotech’s secured promissory note increased to $26,758,106. This figure reflects the original note plus prior amendments and the new $251,000 Fourth Additional New Loan disclosed in the current report.

When does interest start accruing on NKGen Biotech’s new Fourth Additional New Loan?

Interest on the Fourth Additional New Loan begins accruing from January 30, 2026. That date matches when the new $251,000 funding was provided to NKGen Biotech and is specifically clarified in the Alpine Third Amendment to the secured promissory note.

Who are the borrowers under NKGen Biotech’s amended secured promissory note?

The borrowers are NKGen Biotech, Inc. and NKGen Operating Biotech, Inc., its Delaware operating subsidiary. Both entities are jointly identified as the “Borrowers” in the Alpine Third Amendment to the secured promissory note with AlpineBrook Capital GP I Limited.

What exhibit did NKGen Biotech attach related to the Alpine Third Amendment?

NKGen Biotech attached Exhibit 10.1, titled “Amendment No. 3 to Secured Promissory Note issued to the AlpineBrook Capital GP I Limited, dated January 30, 2026.” This exhibit contains the detailed terms governing the latest amendment to the company’s secured note.