8-K

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): August 29, 2025

Equillium, Inc.

(Exact name of Registrant as Specified in Its Charter)

Registrant’s Telephone Number, Including Area Code: (858)

240-1200

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:

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 8.01 Other Events.

On August 29, 2025, Equillium, Inc. (the "Company") received a letter from the Listing Qualifications Department of The Nasdaq Stock Market LLC (“Nasdaq”) notifying the Company that it has regained compliance with the minimum bid price requirement set forth in Nasdaq Listing Rule 5550(a)(2) (the “Bid Price Rule”) for continued inclusion on The Nasdaq Capital Market.

As previously disclosed in the Company’s Current Report on Form 8-K filed on December 13, 2024, the Company received a written notice from Nasdaq on December 13, 2024 notifying the Company that it was not in compliance with the Bid Price Rule because its common stock had failed to meet the $1.00 per share minimum bid price requirement for continued inclusion on The Nasdaq Capital Market. As previously disclosed in the Company’s Current Report on Form 8-K filed on June 13, 2025, the Company received a written notice from Nasdaq on June 12, 2025 notifying the Company that it was granted an additional 180-day period to regain compliance with the Bid Price Rule. To regain compliance with the Bid Price Rule, the Company’s common stock was required to maintain a closing bid price of $1.00 per share or more for at least 10 consecutive business days. This requirement was met on August 28, 2025.

SIGNATURE

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