Ouster COO sells 30,000.5 shares under 10b5-1 plan

Ouster, Inc. Chief Operating Officer Darien Spencer reported an open-market sale of 30,000.5 shares of common stock on May 26, 2026 at a weighted average price of $45.00 per share.

Rhea-AI Filing Summary

Ouster, Inc. Chief Operating Officer Darien Spencer reported an open-market sale of 30,000.5 shares of common stock on May 26, 2026 at a weighted average price of $45.00 per share. The sale was made pursuant to a pre-established Rule 10b5-1 trading plan dated November 18, 2025, indicating it was pre-scheduled rather than discretionary.

After this transaction, Spencer directly holds 342,365.5 shares of Ouster common stock. This balance includes 991 shares acquired on May 15, 2026 through the company’s Amended and Restated 2022 Employee Stock Purchase Plan, so he retains a substantial equity stake following the sale.

Insider Trade Summary 10b5-1

Net Seller: 30,000.5 shares

Net Sell 1 txn

Insider SPENCER DARIEN

Role Chief Operating Officer

Sold 30,000.5 shs ($1.35M)

Type	Security	Shares	Price	Value
Sale	Common Stock	30,000.5	$45.00	$1.35M

Holdings After Transaction: Common Stock — 342,365.5 shares (Direct)

Footnotes (3)

1. F1. Reflects shares sold pursuant to a Rule 10b5-1 plan dated November 18, 2025.
2. F2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $45.00 to $45.18. 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.
3. F3. Includes 991 shares of common stock acquired by Reporting Person on May 15, 2026, pursuant to the Company's Amended and Restated 2022 Employee Stock Purchase Plan.

Key Figures

Shares sold: 30,000.5 shares Weighted average sale price: $45.00 per share Shares owned after transaction: 342,365.5 shares +2 more

5 metrics

Shares sold 30,000.5 shares Common stock sold on May 26, 2026

Weighted average sale price $45.00 per share Open-market sale price range $45.00–$45.18

Shares owned after transaction 342,365.5 shares Direct holdings following May 26, 2026 sale

Recent ESPP acquisition 991 shares Acquired May 15, 2026 under 2022 Employee Stock Purchase Plan

Rule 10b5-1 plan date November 18, 2025 Pre-established trading plan governing the sale

Key Terms

Rule 10b5-1 plan, weighted average price, Employee Stock Purchase Plan, open-market sale

4 terms

Rule 10b5-1 plan regulatory

"Reflects shares sold pursuant to a Rule 10b5-1 plan dated November 18, 2025."

A Rule 10b5-1 plan is a prearranged, written schedule that lets corporate insiders buy or sell company stock at set times or amounts, even if they later learn material nonpublic information. Think of it like setting an automatic thermostat for trades: it creates a clear record that trades were planned in advance, reducing the risk of insider-trading accusations and helping investors trust that insider transactions are routine rather than based on secret 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.

Employee Stock Purchase Plan financial

"Includes 991 shares of common stock acquired ... pursuant to the Company's Amended and Restated 2022 Employee Stock Purchase Plan."

An employee stock purchase plan is a company program that lets workers buy shares through small payroll deductions, often at a discount to the market price and after a set offering period. Think of it like a workplace savings plan that turns into ownership: it encourages employees to share in the company’s success and can create predictable buying or selling of stock that investors watch because it affects supply, demand and employee incentives.

open-market sale financial

"transaction_action": "open-market sale""

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did OUST Chief Operating Officer Darien Spencer report?

Darien Spencer reported selling 30,000.5 Ouster common shares in an open-market transaction at a weighted average price of $45.00 per share. The trade was executed under a pre-established Rule 10b5-1 plan, indicating it was scheduled in advance rather than timed opportunistically.

How many OUST shares does Darien Spencer hold after this Form 4 sale?

Following the reported sale, Darien Spencer directly holds 342,365.5 shares of Ouster common stock. This total includes 991 shares he acquired on May 15, 2026, through the company’s Amended and Restated 2022 Employee Stock Purchase Plan, showing he maintains a significant equity position.

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

The reported sale used a weighted average price of $45.00 per share, with individual trades executed between $45.00 and $45.18. Spencer has committed to provide detailed price and volume breakdowns for each trade within that range upon request to investors or regulators.

Was Darien Spencer’s OUST share sale under a Rule 10b5-1 trading plan?

Yes. The Form 4 footnotes state the 30,000.5 Ouster shares were sold pursuant to a Rule 10b5-1 plan dated November 18, 2025. Such plans pre-schedule trades, which generally reduces the interpretive weight of transaction timing for investors evaluating insider activity.

Did Darien Spencer acquire any OUST shares recently under an employee stock plan?

Yes. The filing notes that Spencer’s post-transaction holdings include 991 Ouster shares acquired on May 15, 2026, through the Amended and Restated 2022 Employee Stock Purchase Plan. This shows ongoing participation in the company’s employee equity programs alongside his open-market sale.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 05/27/2026 - 05:09 PM Learn about SEC filing dates

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)
05/26/2026

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	05/26/2026		S		30,000.5(1)	D	$45(2)	342,365.5(3)	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 pursuant to a Rule 10b5-1 plan dated November 18, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $45.00 to $45.18. 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.

3. Includes 991 shares of common stock acquired by Reporting Person on May 15, 2026, pursuant to the Company's Amended and Restated 2022 Employee Stock Purchase Plan.

	/s/ Megan Chung, as Attorney-in-Fact for Darien Spencer	05/27/2026
	** 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)