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):February 2, 2024

Cellectar Biosciences, Inc.

(Exact name of Registrant as Specified in itsCharter)

100Campus Drive, Florham Park, NJ, 07932

(Address of principal executive offices) (ZipCode)

Registrant’s telephone number, including

area code: (608) 441-8120

N/A

(Former Name or Former Address, if ChangedSince 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. ¨

As a result of the recently announced exercise of Tranche A warrants and other warrant exercises since November 2023, as of January 31, 2024, Cellectar Biosciences, Inc. (the “Company”) had 30,452,042 shares of common stock, 319.76 shares of Series E-2 Preferred Stock, and 918.00 shares of Series E-3 Preferred Stock issued and outstanding. In addition, as of January 31, 2024, the Company also had 111 shares of Series D Preferred Stock issued and outstanding.

SIGNATURES

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.