Ouster (NYSE: OUST) COO sells 10,938 shares in Rule 10b5-1 tax sale

Rhea-AI Filing Summary

Ouster, Inc. Chief Operating Officer Darien Spencer reported an open-market sale of 10,938 shares of common stock on March 12, 2026 at a weighted average price of $23.4328 per share. According to the disclosure, the shares were sold to cover withholding taxes triggered by the vesting and settlement of restricted stock units, under a Rule 10b5-1 “sale to cover” instruction dated August 19, 2025. Following this tax-related sale, Spencer directly holds 325,250 shares of Ouster common stock.

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^*

SPENCER DARIEN

(Last) (First) (Middle)

350 TREAT AVENUE

(Street)

SAN FRANCISCO CA 94110

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Ouster, Inc. [ OUST ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Operating Officer

3. Date of Earliest Transaction (Month/Day/Year)
03/12/2026

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	03/12/2026		S		10,938(1)	D	$23.4328(2)	325,250	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

Explanation of Responses:

1. Reflects shares sold to cover withholding taxes incurred upon the vesting and settlement of restricted stock units pursuant to a Rule 10b5-1 sale to cover instruction letter dated August 19, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $22.9640 to $23.4522. The Reporting Person undertakes to provide 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 set forth in this footnote.

	/s/ Megan Chung, as Attorney-in-Fact for Darien Spencer	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.
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FAQ

What insider transaction did Ouster (OUST) report for COO Darien Spencer?

Ouster reported that COO Darien Spencer sold 10,938 shares of common stock on March 12, 2026. The weighted average sale price was $23.4328 per share, and the transaction was classified as an open-market sale in the Form 4 filing.

Why did Ouster COO Darien Spencer sell 10,938 OUST shares?

The 10,938 shares were sold to cover withholding taxes from the vesting and settlement of restricted stock units. The transaction followed a Rule 10b5-1 “sale to cover” instruction, indicating it was a pre-arranged, tax-related sale rather than a discretionary trade.

What price did Ouster COO Spencer receive for the sold shares?

The filing reports a weighted average sale price of $23.4328 per share. It notes that multiple trades occurred within a price range of $22.9640 to $23.4522, and detailed trade breakdowns are available on request from the issuer or relevant parties.

How many Ouster (OUST) shares does COO Darien Spencer hold after this sale?

After the March 12, 2026 transaction, Darien Spencer directly holds 325,250 shares of Ouster common stock. This context shows the sale was a relatively small portion of his overall holdings and was executed primarily for tax withholding related to RSU vesting.

Was the Ouster COO’s share sale under a Rule 10b5-1 trading plan?

Yes. The filing states the sale was executed pursuant to a Rule 10b5-1 “sale to cover” instruction letter dated August 19, 2025. Such plans pre-schedule trades, indicating the timing of this tax-related sale was established in advance rather than decided opportunistically.