Equillium (EQ) COO exercises options and sells 120,312 shares under plan

Rhea-AI Filing Summary

Equillium, Inc. senior vice president and COO Christine Zedelmayer exercised options to acquire 120,312 shares of common stock at an exercise price of $0.785 per share. She then sold 120,312 shares of common stock at a weighted average price of $2.5003 per share in open-market transactions effected under a Rule 10b5-1 trading plan adopted on August 27, 2025. Following these transactions, she directly holds 62,586 shares of Equillium common stock. The option exercised had been scheduled to vest over four years, with 25% on the first anniversary and the remainder in 36 equal monthly installments.

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).

X

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^*

Zedelmayer Christine

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Sr. Vice President and COO

3. Date of Earliest Transaction (Month/Day/Year)
03/13/2026

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	03/13/2026		M		120,312	A	$0.785	182,898	D
Common Stock	03/13/2026		S(1)		120,312	D	$2.5003(2)	62,586	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
Employee Stock Option (right to buy)	$0.785	03/13/2026		M			120,312	(3)	01/02/2033	Common Stock	120,312	$0	54,688	D

Explanation of Responses:

1. The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 27, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $2.515 to $2.50, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

3. 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/ Christine Zedelmayer	03/16/2026
	** 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 insider transactions did Equillium (EQ) report for Christine Zedelmayer?

Christine Zedelmayer exercised stock options and sold shares. She exercised options for 120,312 shares of Equillium common stock at $0.785 per share, then sold 120,312 shares at a weighted average price of $2.5003 per share in open-market trades.

How many Equillium (EQ) shares did the COO sell and at what price?

The COO sold 120,312 Equillium shares. These common shares were sold in multiple open-market transactions at a weighted average price of $2.5003 per share, with individual trade prices ranging from $2.515 to $2.50, according to the disclosure.

Were Christine Zedelmayer’s Equillium (EQ) share sales pre-planned under a Rule 10b5-1 plan?

Yes, the sale was under a Rule 10b5-1 plan. The filing states the reported sale was effected pursuant to a Rule 10b5-1 trading plan adopted by Christine Zedelmayer on August 27, 2025, indicating the transactions were pre-arranged rather than discretionary.

How many Equillium (EQ) shares does the COO hold after these transactions?

She holds 62,586 Equillium shares after the trades. Following the exercise of 120,312 options and the sale of 120,312 common shares, the Form 4 reports that Christine Zedelmayer’s direct ownership in Equillium common stock stands at 62,586 shares.

What stock options did Equillium (EQ) COO Christine Zedelmayer exercise?

She exercised an employee stock option for 120,312 shares. The option entitled her to buy Equillium common stock at an exercise price of $0.785 per share and was scheduled to vest 25% after one year, with the remainder vesting in 36 equal monthly installments.

How are the Equillium (EQ) sale prices for the COO’s transactions described?

The sale price is reported as a weighted average. The filing notes the $2.5003 figure reflects multiple trades, with shares sold at prices between $2.515 and $2.50, and offers to provide detailed trade-by-trade pricing upon request.