Ouster (NYSE: OUST) COO tax-related sale of 12,559 shares under Rule 10b5-1 plan

Rhea-AI Filing Summary

Ouster, Inc. Chief Operating Officer Darien Spencer reported a sale of 12,559 shares of common stock. The shares were sold at a weighted average price of about $38.82 to $39.54 per share.

According to the disclosure, the sale was made solely to cover withholding taxes incurred when restricted stock units vested and settled, and it was executed pursuant to a Rule 10b5-1 sale-to-cover instruction letter. After this tax-related transaction, Spencer directly holds 329,806.5 shares of Ouster common stock.

Insider Trade Summary 10b5-1

Net Seller: 12,559 shares ($487,578)

Net Sell 1 txn

Insider SPENCER DARIEN

Role Chief Operating Officer

Sold 12,559 shs ($488K)

Type	Security	Shares	Price	Value
Sale	Common Stock	12,559	$38.823	$488K

Holdings After Transaction: Common Stock — 329,806.5 shares (Direct, null)

Footnotes (1)

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. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $38.82 to $39.54. 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.

Key Figures

Shares sold: 12,559 shares Sale price range: $38.82–$39.54 per share Shares held after sale: 329,806.5 shares

3 metrics

Shares sold 12,559 shares Common stock sold on June 12, 2026

Sale price range $38.82–$39.54 per share Weighted-average sale range for the reported transactions

Shares held after sale 329,806.5 shares Direct ownership after the tax-related transaction

Key Terms

restricted stock units, Rule 10b5-1, weighted average price

3 terms

restricted stock units financial

"withholding taxes incurred upon the vesting and settlement of restricted stock units"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Rule 10b5-1 regulatory

"pursuant to a Rule 10b5-1 sale to cover instruction letter"

Rule 10b5-1 is a regulation that allows company insiders to buy or sell their shares at predetermined times, even if they have access to non-public information. It acts like setting a schedule in advance for transactions, helping prevent accusations of unfair trading. This rule provides a way for insiders to plan trades transparently, giving investors confidence that these transactions are not based on hidden information.

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.

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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^*

SPENCER DARIEN

(Last) (First) (Middle)

350 TREAT AVENUE

(Street)

SAN FRANCISCO CALIFORNIA 94110

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/12/2026

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	06/12/2026		S		12,559(1)	D	$38.823(2)	329,806.5	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 $38.82 to $39.54. 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	06/16/2026
	** 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.
* Form 4: SEC 1474 (03-26)

FAQ

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

Ouster reported that Chief Operating Officer Darien Spencer sold 12,559 shares of common stock. The sale was tied to covering withholding taxes on vested restricted stock units and executed under a Rule 10b5-1 sale-to-cover instruction letter.

At what price were the Ouster (OUST) shares sold in Darien Spencer’s Form 4?

The reported price is a weighted average, with sales occurring between $38.82 and $39.54 per share. The filing notes multiple transactions within this range and offers to provide detailed price breakdowns upon request to the issuer, holders, or SEC staff.

Why did Ouster COO Darien Spencer sell shares according to the Form 4 filing?

The shares were sold to cover withholding taxes triggered by the vesting and settlement of restricted stock units. The filing specifies this was a Rule 10b5-1 “sale to cover” transaction, indicating it followed a pre-established instruction letter rather than a discretionary trade.

How many Ouster (OUST) shares does Darien Spencer hold after the reported sale?

Following the transaction, Darien Spencer directly holds 329,806.5 shares of Ouster common stock. This figure comes from the post-transaction ownership column, showing his remaining position after selling 12,559 shares to satisfy tax withholding obligations.

Was Darien Spencer’s Ouster (OUST) share sale part of a Rule 10b5-1 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 arrangements schedule trades in advance, often to manage tax obligations on equity awards like restricted stock units.