Ouster CTO sells 18,778 shares for tax cover

Ouster’s Chief Technology Officer reported a Rule 10b5-1 tax-withholding sale of common stock tied to RSU vesting, retaining a substantial direct share position.

Rhea-AI Filing Summary

Ouster, Inc. (OUST) insider Mark Frichtl, Chief Technology Officer, reported selling 18,778 shares of common stock on September 14, 2026 at a weighted average price of $33.9595 per share. The sale was executed to cover withholding taxes from vesting restricted stock units under a Rule 10b5-1 sale-to-cover instruction. After this tax-related sale, Frichtl directly holds 318,987 shares of Ouster common stock.

Insider Trade Summary 10b5-1

Net Seller: 18,778 shares

Net Sell 1 txn

Insider Frichtl Mark

Role Chief Technology Officer

Sold 18,778 shs ($638K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2	18,778	$33.9595	$638K

Holdings After Transaction: Common Stock — 318,987 shares (Direct)

Footnotes (2)

1. F1. 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 June 9, 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 $33.7168 to $33.9661. 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: 18,778 shares Weighted average sale price: $33.9595 per share Post-transaction holdings: 318,987 shares +3 more

6 metrics

Shares sold 18,778 shares Common stock sale reported for September 14, 2026

Weighted average sale price $33.9595 per share Common stock sold on September 14, 2026

Post-transaction holdings 318,987 shares Directly owned by Mark Frichtl after the sale

Sale price range low $33.7168 per share Lowest price among multiple sale transactions

Sale price range high $33.9661 per share Highest price among multiple sale transactions

Rule 10b5-1 instruction date June 9, 2025 Date of sale-to-cover instruction letter referenced in footnote

Key Terms

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

4 terms

Rule 10b5-1 regulatory

"pursuant to a Rule 10b5-1 sale to cover instruction letter dated June 9, 2025"

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.

withholding taxes financial

"shares sold to cover withholding taxes incurred upon the vesting"

Withholding taxes are amounts a payer or government takes out of payments — such as wages, interest, or dividends — before the recipient gets the money, functioning like a cashier keeping part of a bill to pay taxes on your behalf. For investors this matters because it reduces the cash they actually receive, affects net returns and yield calculations, and may require additional paperwork or treaty claims to recover or offset the withheld amount against final tax bills.

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.

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.

FAQ

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

What insider transaction did OUST disclose for Mark Frichtl on September 14, 2026?

OUST reported that Chief Technology Officer Mark Frichtl sold 18,778 shares of common stock on September 14, 2026 at a weighted average price of $33.9595 per share in a transaction classified as a sale.

Why did the OUST CTO sell 18,778 shares of common stock?

The filing states the 18,778 shares were 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 June 9, 2025.

How many OUST shares does Mark Frichtl hold after this Form 4 transaction?

After the reported sale, Mark Frichtl directly holds 318,987 shares of Ouster, Inc. common stock, according to the Form 4 filing’s post-transaction holdings figure.

What price range did the OUST shares sell for in this insider transaction?

The filing reports a weighted average price of $33.9595 per share, with multiple trades executed in a price range from $33.7168 to $33.9661. Detailed breakdowns by price level are available on request from the reporting person.

Was the OUST insider sale made under a Rule 10b5-1 trading plan?

Yes. The transaction is described as being made pursuant to a Rule 10b5-1 sale to cover instruction letter dated June 9, 2025, and the filing’s Rule 10b5-1 checkbox is affirmed.

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

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Available on EDGAR 09/16/2026 - 06:51 PM Accepted by SEC EDGAR 09/16/2026 - 06:51 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^*

Frichtl Mark

(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 Technology Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/14/2026

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	09/14/2026		S		18,778(1)	D	$33.9595(2)	318,987	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 June 9, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $33.7168 to $33.9661. 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.

Remarks:

Exhibit List - Exhibit 24 - Power of Attorney

	/s/ Kenneth Gianella, as Attorney-in-Fact for Mark Frichtl	09/16/2026
	** 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)