Equillium (EQ) COO sells 14,584 shares after exercising stock options

Rhea-AI Filing Summary

Equillium, Inc. senior vice president and COO Christine Zedelmayer reported an exercise-and-sale transaction in company stock. She exercised employee stock options to acquire 14,584 shares of common stock at an exercise price of $0.7850 per share, then sold 14,584 shares in an open-market transaction at a weighted average price of $2.9304 per share.

The sale was executed under a pre-arranged Rule 10b5-1 trading plan adopted on August 27, 2025, indicating it was scheduled in advance. After these transactions, she holds 62,586 shares of common stock directly and 25,521 stock options that remain outstanding and unexercised.

Insider Trade Summary 10b5-1

Net Seller: 14,584 shares ($42,737)

Net Sell 3 txns

Insider Zedelmayer Christine

Role Sr. Vice President and COO

Sold 14,584 shs ($43K)

Type	Security	Shares	Price	Value
Exercise	Employee Stock Option (right to buy)	14,584	$0.00	--
Exercise	Common Stock	14,584	$0.785	$11K
Sale	Common Stock	14,584	$2.9304	$43K

Holdings After Transaction: Employee Stock Option (right to buy) — 25,521 shares (Direct, null); Common Stock — 77,170 shares (Direct, null)

Footnotes (1)

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. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $2.91 to $2.95, 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. 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.

Key Figures

Shares sold: 14,584 shares Weighted average sale price: $2.9304 per share Shares acquired via option exercise: 14,584 shares +4 more

7 metrics

Shares sold 14,584 shares Open-market sale of common stock

Weighted average sale price $2.9304 per share Common stock sale range $2.91–$2.95

Shares acquired via option exercise 14,584 shares Common stock from employee stock option exercise

Option exercise price $0.7850 per share Employee stock option exercise price

Common shares held after transactions 62,586 shares Direct ownership following exercise and sale

Options remaining after exercise 25,521 options Employee stock options still outstanding

Option expiration date 2033-01-02 Employee stock option grant expiration

Key Terms

Rule 10b5-1 trading plan, weighted average price, Employee Stock Option (right to buy), vests in 36 equal monthly installments

4 terms

Rule 10b5-1 trading plan regulatory

"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."

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

Employee Stock Option (right to buy) financial

"Employee Stock Option (right to buy)"

vests in 36 equal monthly installments financial

"and the remainder vests in 36 equal monthly installments thereafter for the following three years."

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Form 4 Insider Transactions: What Each Field Means →

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

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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 CALIFORNIA 92037

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/05/2026

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

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

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

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	06/05/2026		M		14,584	A	$0.785	77,170	D
Common Stock	06/05/2026		S(1)		14,584	D	$2.9304(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	06/05/2026		M			14,584	(3)	01/02/2033	Common Stock	14,584	$0	25,521	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 $2.91 to $2.95, 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	06/05/2026
	** 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.
* Form 4: SEC 1474 (03-26)

FAQ

What did Equillium (EQ) COO Christine Zedelmayer do in this Form 4 filing?

Christine Zedelmayer exercised employee stock options and then sold the same number of Equillium shares. She acquired 14,584 shares at an exercise price of $0.7850 and sold 14,584 shares in the open market at a weighted average price of $2.9304.

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

She sold 14,584 shares of Equillium common stock. The weighted average sale price was $2.9304 per share, with individual trades executed between $2.91 and $2.95, according to the transaction details and related footnote disclosure.

At what price did the Equillium (EQ) COO exercise her stock options?

She exercised employee stock options covering 14,584 shares at an exercise price of $0.7850 per share. These options related to Equillium common stock and were part of a standard employee stock option grant with time-based vesting conditions.

How many Equillium (EQ) shares does the COO own after the reported transactions?

Following the reported option exercise and share sale, Christine Zedelmayer directly holds 62,586 shares of Equillium common stock. She also has 25,521 employee stock options that remain outstanding and unexercised, according to the post-transaction ownership figures.

Was the Equillium (EQ) COO’s stock sale part of a Rule 10b5-1 trading plan?

Yes, the sale was executed under a Rule 10b5-1 trading plan. A footnote states the plan was adopted on August 27, 2025, indicating the transactions were pre-scheduled rather than discretionary, which is common for routine insider equity sales.

What is the remaining option position for the Equillium (EQ) COO after this Form 4?

After exercising 14,584 options, she has 25,521 employee stock options remaining outstanding. The option grant carries a vesting schedule where 25% vests after one year, with the balance vesting in 36 equal monthly installments over the following three years.