[Form 4] SHOULDER INNOVATIONS, INC. Insider Trading Activity

Rhea-AI Filing Summary

Matthew Fraser Ahearn, Chief Operating Officer and Director of Shoulder Innovations, Inc. (SI), reported option and related common stock transactions dated 09/11/2025. The filing shows acquisitions of three option tranches exercisable into common stock: 12,286 options at a $0.9349 exercise price, 78,616 options at $2.0988, and 16,443 options at $2.4804. Following these reported transactions, the filing records beneficial ownership rising to 215,379 common shares (direct). The first option tranche is fully vested and exercisable; the third tranche vests one-fourth on April 19, 2024 and the remainder in 36 monthly increments. The form is signed by an attorney-in-fact on 09/15/2025.

Positive

• Increased insider stake: Beneficial ownership reported at 215,379 shares after the transactions.
• Clear vesting disclosure: Filing specifies that one tranche is fully exercisable and details the monthly vesting schedule for another tranche.

Negative

• None.

Insights

Securities Analyst

TL;DR: Insider option acquisitions increased direct beneficial ownership to 215,379 shares, materially altering insider stake.

The reporting person, who serves as COO and Director, recorded multiple option grants/exercises on 09/11/2025 that add 107,345 options and related common shares to his holdings when aggregated with prior positions. The filing specifies exercise prices across three tranches and confirms full exercisability for the first tranche, with staggered vesting on the third tranche. For investors this is a clear, contemporaneous disclosure of insider equity accumulation and vesting schedules; it does not include cashflow details beyond exercise prices or indicate whether shares were exercised or remain outstanding as exercisable options versus stock delivered.

Corporate Governance Expert

TL;DR: Governance disclosure is complete on vesting and ownership; signatures filed via attorney-in-fact consistent with practice.

The Form 4 properly identifies the reporting person, relationship to the issuer (COO and Director), transaction dates, exercise prices, and vesting language. The explanation clarifies vesting mechanics for the third tranche and confirms exercisability for the first tranche. The form was executed by an attorney-in-fact, and the filing includes required detail on post-transaction beneficial ownership. No governance irregularities or omissions are apparent from the disclosed fields.

SEC Form 4

FORM 4

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
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Ahearn Matthew Fraser

(Last) (First) (Middle)

C/O SHOULDER INNOVATIONS, INC.

1535 STEELE AVENUE SW, SUITE B

(Street)

GRAND RAPIDS MI 49507

(City) (State) (Zip)

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		10% Owner
X	Officer (give title below)		Other (specify below)
	CHIEF OPERATING OFFICER

3. Date of Earliest Transaction (Month/Day/Year)
09/11/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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	09/11/2025		M		12,286	A	$0.9349	120,320	D
Common Stock	09/11/2025		M		78,616	A	$2.0988	198,936	D
Common Stock	09/11/2025		M		16,443	A	$2.4804	215,379	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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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
Stock Option	$0.9349	09/11/2025		M			12,286	(1)	10/23/2027	Common Stock	12,286	$0	0	D
Stock Option	$2.0988	09/11/2025		M			78,616	(1)	12/16/2030	Common Stock	78,616	$0	0	D
Stock Option	$2.4804	09/11/2025		M			16,443	(2)	05/09/2033	Common Stock	16,443	$0	16,285	D

Explanation of Responses:

1. The stock option is fully vested and currently exercisable.

2. The stock option vested as to one-fourth of the underlying shares on April 19, 2024, and the remaining shares vest in 36 equal increments on the last day of each calendar month thereafter.

	/s/ Jeffrey Points, as Attorney-in-Fact	09/15/2025
	** Signature of Reporting Person	Date
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.
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FAQ

What did SI insider Matthew Fraser Ahearn acquire on 09/11/2025?

The filing reports acquisitions of stock options convertible into common stock: 12,286 at $0.9349, 78,616 at $2.0988, and 16,443 at $2.4804.

How many SI shares does the reporting person beneficially own after the transactions?

The Form 4 shows beneficial ownership totaling 215,379 common shares (direct) following the reported transactions.

Are any of the reported options exercisable now?

Yes. The filing states the first option tranche (12,286) is fully vested and currently exercisable; the third tranche vests over time as described.

What is the vesting schedule for the third option tranche?

The third tranche vested one-fourth on April 19, 2024 with the remaining shares vesting in 36 equal monthly increments on the last day of each calendar month.

Who signed the Form 4 and when?

The Form 4 was signed by Jeffrey Points, as Attorney-in-Fact on 09/15/2025.