Sec Form 4 Filing - Tansey Casey M @ SHOULDER INNOVATIONS, INC. - 2026-06-26

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

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1. Name and Address of Reporting Person Tansey Casey M 2. Issuer Name and Ticker or Trading Symbol SHOULDER INNOVATIONS, INC. [ SI] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O SHOULDER INNOVATIONS, INC., 1535 STEELE AVENUE SW, SUITE B 3. Date of Earliest Transaction (MM/DD/YY) 06/26/2026 (Street) GRAND RAPIDS, MI49507 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 06/26/2026 A 5,046 ( 1 ) A $ 0 52,712 D Common Stock 1,686,403 I Held by U.S. Venture Partners XII, L.P. ( 2 ) ( 3 ) Common Stock 85,586 I Held by U.S. Venture Partners XII-A, L.P. ( 2 ) ( 3 ) Common Stock 921,130 I Held by U.S. Venture Partners Select Fund I, L.P. ( 2 ) ( 3 )

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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Tansey Casey M C/O SHOULDER INNOVATIONS, INC. 1535 STEELE AVENUE SW, SUITE B GRAND RAPIDS, MI49507 X X Signatures /s/ Jeffrey Points, as Attorney-in-Fact 06/29/2026 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents an award of restricted stock units ("RSUs"). The RSUs will vest on the earlier of the date of the annual meeting of stockholders to be held in 2027 or June 26, 2027. Each RSU represents a contingent right to receive one share of the Issuer's Common Stock and has no expiration date. The Reporting Person voluntarily elected to defer receipt of the Common Stock issuable upon settlement of the RSUs until the Reporting Person's departure from the Board of Directors. ( 2 )Presidio Management Group XII, L.L.C. ("PMG XII") is the general partner of U.S. Venture Partners XII, L.P. ("USVP XII") and U.S. Venture Partners XII-A, L.P. ("USVP XII-A") and has sole voting and dispositive power with respect to the shares held by USVP XII and USVP XII-A. Steven M. Krausz, Richard W. Lewis, Jonathan D. Root and Dafina Toncheva are the managing members of PMG XII, and share voting and dispositive power with respect to the shares held by USVP XII and USVP XII-A. Casey M. Tansey is the managing partner of PMG XII and may be deemed to share voting and dispositive power over the reported securities held by USVP XII and USVP XII-A. Presidio Management Group Select Fund I, L.L.C. ("PMG Select") is the general partner of U.S. Venture Partners Select Fund I, L.P. ("USVP SFI"), and U.S. Venture Partners Select Fund I-A, L.P. ("USVP SFI-A") and has sole voting and dispositive power with respect to the shares held by USVP SFI on its own behalf and as nominee for USVP SFI-A. ( 3 )Richard W. Lewis, Jonathan D. Root and Dafina Toncheva are the managing members of PMG Select and share voting and dispositive power with respect to the shares held by USVP SFI on its own behalf and as nominee for USVP SFI-A. Casey M. Tansey, a member of the Issuer's board of directors, is the managing partner of PMG Select and may be deemed to share voting and dispositive power with respect to the shares held by USVP SFI on its own behalf and as nominee for USVP SFI-A. Each of the managing members and managing partner of PMG XII and PMG Select disclaims beneficial ownership of such holdings, except to the extent of their pecuniary interest in the shares.

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).

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