Michael A. Carusi - Jul 30, 2025 Form 3 Insider Report for SHOULDER INNOVATIONS, INC. (SI)

Role: Director, 10%+ Owner
Signature: /s/ Jeffrey S. Points, as Attorney-in-Fact
Stock symbol: SI
Transactions as of: Jul 30, 2025
Transactions value $: $0
Form type: 3
Date filed: 7/30/2025, 09:38 PM
Next filing: Aug 5, 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Carusi Michael A	Director, 10%+ Owner	C/O SHOULDER INNOVATIONS, INC., 1535 STEELE AVENUE SW, SUITE B, GRAND RAPIDS	/s/ Jeffrey S. Points, as Attorney-in-Fact	2025-07-30	0001306506

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
holding	SI	Series C Convertible Preferred Stock							Jul 30, 2025	Common Stock	1.1M		See Footnote	F1, F2
holding	SI	Series D Convertible Preferred Stock							Jul 30, 2025	Common Stock	521K		See Footnote	F1, F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Immediately prior to the closing of the Issuer's initial public offering, the shares of preferred stock of the Issuer will automatically convert into shares of Common Stock on a one-for-0.052410901 basis. The shares of preferred stock have no expiration date.
F2	Consists of (i) 1,036,638 shares of Common Stock underlying Series C Preferred Stock, and 492,833 shares of Common Stock underlying Series D Preferred Stock held by Lightstone Ventures II, L.P. ("LSV II"); and (ii) 60,333 shares of Common Stock underlying Series C Preferred Stock and 28,666 shares of Common Stock underlying Series D Preferred Stock held by Lightstone Ventures II (A), L.P. ("LSV II (A)"). LSV Associates II, LLC is the general partner of LSV II and LSV II (A) and has sole voting and dispositive power with respect to the shares held by LSV II and LSV II (A). The reporting person is a managing director of LSV Associates II, LLC, and shares voting and dispositive power with respect to the shares held of record by LSV II and LSV II (A). The reporting person disclaims beneficial ownership of such holdings, except to the extent of his pecuniary interest in the shares.

Content

Immediately prior to the closing of the Issuer's initial public offering, the shares of preferred stock of the Issuer will automatically convert into shares of Common Stock on a one-for-0.052410901 basis. The shares of preferred stock have no expiration date.

Consists of (i) 1,036,638 shares of Common Stock underlying Series C Preferred Stock, and 492,833 shares of Common Stock underlying Series D Preferred Stock held by Lightstone Ventures II, L.P. ("LSV II"); and (ii) 60,333 shares of Common Stock underlying Series C Preferred Stock and 28,666 shares of Common Stock underlying Series D Preferred Stock held by Lightstone Ventures II (A), L.P. ("LSV II (A)"). LSV Associates II, LLC is the general partner of LSV II and LSV II (A) and has sole voting and dispositive power with respect to the shares held by LSV II and LSV II (A). The reporting person is a managing director of LSV Associates II, LLC, and shares voting and dispositive power with respect to the shares held of record by LSV II and LSV II (A). The reporting person disclaims beneficial ownership of such holdings, except to the extent of his pecuniary interest in the shares.

Remarks:

Exhibit 24.1 - Power of Attorney