Ambiq COO exercises options, sells 15,000 shares

Ambiq Micro, Inc. (AMBQ) reported that President and COO Sean Chihhsiang Chen exercised stock options and sold common shares on September 14, 2026 under a pre-arranged Rule 10b5-1 trading plan adopted on June 5, 2026.

Rhea-AI Filing Summary

Ambiq Micro, Inc. (AMBQ) reported that President and COO Sean Chihhsiang Chen exercised stock options and sold common shares on September 14, 2026 under a pre-arranged Rule 10b5-1 trading plan adopted on June 5, 2026.

He exercised options to acquire 15,000 shares of common stock at an exercise price of $8.12 per share, then sold a total of 15,000 shares of common stock in multiple transactions at weighted average prices of $59.36, $60.24, and $60.83 per share. Following the option exercise, he continued to hold stock options covering 134,423 shares of Ambiq Micro common stock that remain outstanding and unexercised.

Insider Trade Summary 10b5-1

Exercise and Sale: 15,000 shares ($780K approx. pre-tax spread)

Exercise and Sale 5 txns

Insider Chen Sean Chihhsiang

Role President and COO

Sold 15,000 shs ($902K)

Approx. gross sale proceeds $902K

Approx. exercise cost $122K

Approx. pre-tax spread $780K

Type	Security	Shares	Price	Value
Exercise	Stock Option (Right to Buy) F1, F5	15,000	$0.00	$0.00
Exercise	Common Stock F1	15,000	$8.12	$122K
Sale	Common Stock F1, F2	2,600	$59.3637	$154K
Sale	Common Stock F1, F3	11,000	$60.238	$663K
Sale	Common Stock F1, F4	1,400	$60.8332	$85K

Holdings After Transaction: Stock Option (Right to Buy) — 134,423 contracts (Direct); Common Stock — 120,275 shares (Direct)

Footnotes (5)

1. F1. The transactions reported in this Form 4 occurred under a Rule 10b5-1 plan adopted by the Reporting Person on June 5, 2026
2. F2. The reported price in Column 4 is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from $58.63 to $59.57 per share. 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 set forth in this footnote.
3. F3. The reported price in Column 4 is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from $59.67 to $60.66 per share. 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 set forth in this footnote.
4. F4. The reported price in Column 4 is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from $60.72 to $61.06 per share. 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 set forth in this footnote.
5. F5. 1/4 of the shares subject to the option vested on February 21, 2020, and 1/48 of the shares subject to the option vested in equal monthly installments thereafter, subject to the Reporting Person's continued service.

Key Figures

Options exercised: 15,000 shares Option exercise price: $8.12 per share Shares sold (first tranche): 2,600 shares at $59.36 per share +5 more

8 metrics

Options exercised 15,000 shares Common stock acquired by exercising options on September 14, 2026

Option exercise price $8.12 per share Exercise price for 15,000 options converted into common stock

Shares sold (first tranche) 2,600 shares at $59.36 per share Weighted average sale price; sales within $58.63–$59.57 range

Shares sold (second tranche) 11,000 shares at $60.24 per share Weighted average sale price; sales within $59.67–$60.66 range

Shares sold (third tranche) 1,400 shares at $60.83 per share Weighted average sale price; sales within $60.72–$61.06 range

Remaining stock options 134,423 shares Stock options remaining outstanding after the reported option exercise

Option vesting start February 21, 2020 One quarter of the option vested on this date, with monthly vesting thereafter

Option expiration February 20, 2029 Expiration date of the option exercised in this transaction

Key Terms

Rule 10b5-1 plan, weighted average sale price, vested, equal monthly installments

4 terms

Rule 10b5-1 plan regulatory

"occurred under a Rule 10b5-1 plan adopted by the Reporting Person"

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 sale price financial

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

vested other

"1/4 of the shares subject to the option vested on February 21, 2020"

equal monthly installments other

"1/48 of the shares subject to the option vested in equal monthly installments"

FAQ

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

What insider transactions did AMBQ’s President and COO report on this Form 4?

Sean Chihhsiang Chen reported exercising stock options for 15,000 shares of Ambiq Micro common stock at an exercise price of $8.12 per share and selling 15,000 shares of common stock in market transactions on September 14, 2026.

How many AMBQ shares did the insider sell and at what prices?

Sean Chihhsiang Chen sold a total of 15,000 shares of Ambiq Micro common stock: 2,600 shares at a weighted average of $59.36, 11,000 shares at $60.24, and 1,400 shares at $60.83 per share, each in multiple transactions within stated price ranges.

At what price were the AMBQ stock options exercised in this filing?

The reported stock options were exercised to acquire 15,000 shares of Ambiq Micro common stock at an exercise price of $8.12 per share on September 14, 2026.

Were the AMBQ insider transactions made under a Rule 10b5-1 plan?

Yes. A footnote states that the transactions reported occurred under a Rule 10b5-1 plan adopted by Sean Chihhsiang Chen on June 5, 2026.

How many Ambiq Micro options does the insider hold after these transactions?

After exercising options for 15,000 shares, Sean Chihhsiang Chen continued to hold stock options covering 134,423 shares of Ambiq Micro common stock, with the option reported in this filing expiring on February 20, 2029.

How were the AMBQ sale prices described in the Form 4 footnotes?

Each sale tranche’s price is described as a weighted average sale price, with shares sold in multiple transactions within price ranges, including $58.63 to $59.57, $59.67 to $60.66, and $60.72 to $61.06 per share.

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

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Available on EDGAR 09/15/2026 - 06:58 PM Accepted by SEC EDGAR 09/15/2026 - 06:57 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^*

Chen Sean Chihhsiang

(Last) (First) (Middle)

C/O AMBIQ MICRO, INC.

6500 RIVER PLACE BLVD BUILDING 7 STE 200

(Street)

AUSTIN TEXAS 78730

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Ambiq Micro, Inc. [ AMBQ ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President and COO

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		M(1)		15,000	A	$8.12	135,275	D
Common Stock	09/14/2026		S(1)		2,600	D	$59.3637(2)	132,675	D
Common Stock	09/14/2026		S(1)		11,000	D	$60.238(3)	121,675	D
Common Stock	09/14/2026		S(1)		1,400	D	$60.8332(4)	120,275	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
Stock Option (Right to Buy)	$8.12	09/14/2026		M(1)			15,000	(5)	02/20/2029	Common Stock	15,000	$0	134,423	D

Explanation of Responses:

1. The transactions reported in this Form 4 occurred under a Rule 10b5-1 plan adopted by the Reporting Person on June 5, 2026

2. The reported price in Column 4 is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from $58.63 to $59.57 per share. 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 set forth in this footnote.

3. The reported price in Column 4 is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from $59.67 to $60.66 per share. 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 set forth in this footnote.

4. The reported price in Column 4 is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from $60.72 to $61.06 per share. 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 set forth in this footnote.

5. 1/4 of the shares subject to the option vested on February 21, 2020, and 1/48 of the shares subject to the option vested in equal monthly installments thereafter, subject to the Reporting Person's continued service.

	/s/ Jeffrey Winzeler, Attorney-in-Fact	09/15/2026
	** 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)