Sec Form 4 Filing - Sidow Kevin @ CARLSMED, INC. - 2025-07-22

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Sidow Kevin 2. Issuer Name and Ticker or Trading Symbol CARLSMED, INC. [ CARL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O CARLSMED, INC., 1800 ASTON AVE., SUITE 100 3. Date of Earliest Transaction (MM/DD/YY) 07/22/2025 (Street) CARLSBAD, CA92008 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 07/22/2025 A 17,333 ( 1 ) ( 2 ) A $ 0 17,333 ( 2 ) D Common Stock 07/24/2025 M 28,900 A 28,900 D Common Stock 07/24/2025 P 13,333 ( 4 ) A $ 15 59,566 ( 5 ) D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Series B Preferred Stock ( 3 ) 07/24/2025 C 28,900 ( 3 ) ( 3 ) Common Stock 28,900 ( 3 ) 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Sidow Kevin C/O CARLSMED, INC. 1800 ASTON AVE., SUITE 100 CARLSBAD, CA92008 X Signatures /s/ Leonard Greenstein, as attorney-in-fact for Kevin Sidow 07/24/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Constitute an award of restricted stock units ("RSUs") for which the Reporting Person is entitled to receive one (1) share of Common Stock for each RSU upon vesting. The RSUs will vest in equal annual installments over three years. ( 2 )Includes 17,333 unvested restricted stock units convertible into approximately 17,333 shares of the Issuer's common stock. ( 3 )These securities were previously reported on a Form 3 filed by the Reporting Person as preferred stock of the Issuer. Each share of preferred stock of the Issuer converted into one share of the Issuer's common stock immediately prior to the closing of the Issuer's initial public offering on a 1-to-1 basis without payment of additional consideration. The preferred stock has no expiration date. ( 4 )Includes 13,333 shares of the Issuer's common stock purchased by the Reporting Person in the Issuer's initial public offering at the public offering price of $15.00 per share. The purchase was made directly from the underwriters in connection with the offering. ( 5 )Includes (i) 17,333 unvested RSUs convertible into approximately 17,333 shares of the Issuer's common stock, (ii) 28,900 shares of common stock issued to Reporting Person upon the conversion of outstanding preferred stock on a 1-to-1 basis, immediately prior to the closing of the Issuer's public offering, and (iii) 13,333 shares of the Issuer's common stock purchased by the Reporting Person in the Issuer's initial public offering at the public offering price of $15.00 per share.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.