[Form 4] Equillium, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Bruce D. Steel, who is identified as President and CEO, Director and a 10% owner of Equillium, Inc. (EQ), reported a grant of an employee stock option on 08/29/2025. The option covers 1,695,000 shares of common stock at an exercise price of $1.74 per share and is exercisable through 08/28/2035. The report was signed on 09/02/2025.

The option vests with 25% vesting on the first anniversary of the vesting commencement date and the remainder vesting in 36 equal monthly installments over the following three years. The filing indicates direct beneficial ownership of the underlying shares following the grant.

Positive

• Alignment of interests: Multi-year vesting ties the CEO's compensation to long-term share performance.
• Retention incentive: The vesting schedule with monthly installments supports executive retention over four years.

Negative

• Potential dilution: Grant of 1,695,000 options could increase shares outstanding if exercised, affecting existing shareholders.
• Insufficient disclosure: Form 4 does not provide total shares outstanding or board approval details to assess materiality fully.

Insights

Financial Analyst

TL;DR: Large option grant to CEO could affect dilution and aligns management with equity performance.

The disclosed grant of 1,695,000 options at $1.74 strikes is a material compensation event for management, increasing potential common shares outstanding if exercised. The long ten-year term and multi-year vesting tie executive incentives to long-term share performance. Without additional context on total shares outstanding or prior grants, the exact dilution and expense impact cannot be quantified from this filing alone.

Corporate Governance Expert

TL;DR: Standard multi-year vesting and long exercise window; requires disclosure context for full governance assessment.

The vesting schedule—25% after one year then monthly over three years—is a common structure to retain leadership. The form confirms the reporting person is both CEO and a 10% owner, which is relevant for oversight and related-party considerations. The filing itself provides clear mechanics but lacks comparative context such as board approval details or prior awards.

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^*

Steel Bruce D.

(Last) (First) (Middle)

2223 AVENIDA DE LA PLAYA, SUITE 105

(Street)

LA JOLLA CA 92037

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Equillium, Inc. [ EQ ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	X	10% Owner
X	Officer (give title below)		Other (specify below)
	President and CEO

3. Date of Earliest Transaction (Month/Day/Year)
08/29/2025

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

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
Employee Stock Option (right to buy)	$1.74	08/29/2025		A		1,695,000		(1)	08/28/2035	Common Stock	1,695,000	$0	1,695,000	D

Explanation of Responses:

1. Twenty-five percent of the shares subject to the option vests on the first anniversary of the vesting commencement date, and the remainder vests in 36 equal monthly installments thereafter for the following three years.

	/s/ Bruce D. Steel	09/02/2025
	** 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.
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.

FAQ

What did Bruce D. Steel report on Form 4 for Equillium (EQ)?

He reported an employee stock option grant covering 1,695,000 shares at an exercise price of $1.74, dated 08/29/2025.

What is the vesting schedule for the option reported by Bruce D. Steel?

The option vests 25% on the first anniversary of the vesting commencement date, with the remainder vesting in 36 equal monthly installments over the next three years.

How long is the exercise window for the option grant?

The option shows an expiration/exercise date of 08/28/2035, giving a ten-year term from the grant date.

When was the Form 4 signed and filed?

The filing bears the reporting person's signature dated 09/02/2025.

What roles does Bruce D. Steel hold at Equillium as listed on the Form 4?

He is listed as President and CEO, a Director, and a 10% owner of Equillium.