AMBQ insider ownership: who sold, why, and what they still hold

What stands out

Five insiders sold $19.9M with no disclosed plan: Timothy Chen ($5.6M), Scott Hanson ($4.3M) and Fumihide Esaka ($4.2M), plus 2 more. The filings don't state a reason.Timothy Chen: largest such sale, May 27, 2026 · Scott Hanson: largest such sale, Aug 26, 2026 · Fumihide Esaka: largest such sale, May 14, 2026

Selling picked up in the last 90 days: officers and directors sold 339K shares, against an average of 79K per 90 days earlier in the period. Most of it was Fumihide Esaka (202K shares in the last 90 days) and Scott Hanson (78K shares in the last 90 days); 71% of these sales were under disclosed plans.Fumihide Esaka: largest recent sale, Sep 1, 2026 · Scott Hanson: largest recent sale, Aug 26, 2026

A share of stake is shown for 0 of the 8 officers and directors who sold. 10 are left out

Left out: Wen HSIEH, Fumihide Esaka, Scott Hanson, Timothy Chen, Joseph Tautges, Sean Chen, Jeffrey Winzeler, Ker Zhang, Michele Connors and Bernard Banks (share of stake is being verified).

Disclosed company stock is not an insider's whole wealth.

Who sold, and how much of their stake

Officers and directors, past 12 months. Their share of stake is being verified and is not shown yet; amounts and trading plans are below.

Fumihide Esaka

Chief Executive Officer, Director

Not confirmed

Share of stake not shown: share of stake is being verified. Why

$16.4M67% planned, 7% to cover taxes 26% no plan disclosed

Sean Chen

President and COO

Not confirmed

Share of stake not shown: share of stake is being verified. Why

$6.7M41% planned 59% no plan disclosed

Scott Hanson

Chief Technology Officer, Director

Not confirmed

Share of stake not shown: share of stake is being verified. Why

$5.8M15% planned, 10% to cover taxes 74% no plan disclosed

Timothy Chen

Director

Not confirmed

Share of stake not shown: share of stake is being verified. Why

$5.6MNo plan disclosed

Jeffrey Winzeler

Chief Financial Officer

Not confirmed

Share of stake not shown: share of stake is being verified. Why

$2.2M17% to cover taxes 83% no plan disclosed

All 8 sellers

Selling by month

Officers and directors, Oct 2025 to Oct 2026. Each sale is counted once: under a disclosed plan, else to cover taxes, else no plan disclosed.

Disclosed planTo cover taxesNo plan disclosedOne dollar scale for every month; the tallest bar is labeled

Recent activity

Past 30 days, Sep 17, 2026 to Oct 16, 2026

Oct 5, 2026Sean Chen sold 8.2K shares ($548K) under a disclosed trading plan.

Who	Shares	Price	% of total stake	Total stake after	Trade date	Filed
Sean Chen President and COO	8,205	$66.78	n/a	n/a	Oct 5, 2026	Oct 6, 2026

Oct 2, 20264 executives sold 36K shares ($2.5M) to cover taxes on vesting stock.

Who	Shares	Price	% of total stake	Total stake after	Trade date	Filed
Fumihide Esaka Chief Executive Officer, Director	16,560	$69.60	n/a	n/a	Oct 2, 2026	Oct 6, 2026
Scott Hanson Chief Technology Officer, Director	8,680	$69.60	n/a	n/a	Oct 2, 2026	Oct 6, 2026
Sean Chen President and COO Also under a disclosed plan	5,802	$69.60	n/a	n/a	Oct 2, 2026	Oct 6, 2026
Jeffrey Winzeler Chief Financial Officer	5,455	$69.60	n/a	n/a	Oct 2, 2026	Oct 6, 2026

"% of total stake" is the shares in an event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings are not confirmed, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.

Outside holders, reported separately

KPCB XVI Associates, LLC reported no open-market sales in the past 12 months. Large shareholders and the funds or companies that board members represent are not part of management, so they are left out of the figures above.

Details

Common questions

Is the Ambiq Micro, Inc. CEO selling stock?

Yes. Fumihide Esaka sold 262K shares ($16.4M) in the past 12 months, 67% of it under a trading plan disclosed in the filings.

Why are Ambiq Micro, Inc. insiders selling?

Filings rarely give a reason, and we don't guess at one. What they show is how the sales were made: 39% of sales by value ran under 10b5-1 trading plans disclosed in the filings, 6% were to cover taxes and 55% had no disclosed plan. A trading plan schedules sales in advance.

Are any Ambiq Micro, Inc. insiders buying?

No. Officers and directors reported no purchases in the past 12 months.

The evidence

Who sold8 officers and directors: amount, % of holdings, trading plan

Who sold	Amount	% of holdings	Trading plan
Fumihide Esaka Chief Executive Officer, Director	$16.4M 262K shares	Not confirmed share of stake is being verified. Why	67% under a disclosed plan, 7% to cover taxes 26% no plan disclosed
Sean Chen President and COO	$6.7M 100K shares	Not confirmed share of stake is being verified. Why	41% under a disclosed plan 59% no plan disclosed
Scott Hanson Chief Technology Officer, Director	$5.8M 98K shares	Not confirmed share of stake is being verified. Why	15% under a disclosed plan, 10% to cover taxes 74% no plan disclosed
Timothy Chen Director	$5.6M 71K shares	Not confirmed share of stake is being verified. Why	No plan disclosed
Jeffrey Winzeler Chief Financial Officer	$2.2M 31K shares	Not confirmed share of stake is being verified. Why	17% to cover taxes 83% no plan disclosed
Ker Zhang Director	$645K 10K shares	Not confirmed share of stake is being verified. Why	No plan disclosed
Joseph Tautges Director	$242K 7.8K shares	Not confirmed share of stake is being verified. Why	No plan disclosed
Michele Connors General Counsel	$21K 811 shares	Not confirmed share of stake is being verified. Why	To cover taxes

Outside holder, reported separately: KPCB XVI Associates, LLC (a 10% owner, not part of management). No open-market sales reported in the period. Latest filing

The full ownership picture0 of 10 officers and directors confirmed

Vested shares across all share classes, held directly and through trusts, LLCs and family members, as reported on SEC Forms 3, 4 and 5. Unvested awards and options are never counted as owned shares.

Insider

Held Oct 16, 2025

Sold

Held Oct 16, 2026

Still held

Wen HSIEH

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Wen HSIEH are complete.

Director

n/a

Vesting, gifts, unvested awards and holding lines for Wen HSIEH

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Wen HSIEH are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Fumihide Esaka

Chief Executive Officer, Director

n/a

−262K

n/a

Vesting, gifts, unvested awards and holding lines for Fumihide Esaka

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Fumihide Esaka are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
58,507	$8.12	Feb 20, 2029	$3.6M
144,279	$12.60	Jul 20, 2034	$8.2M

Estimate: options held × ($69.51 − strike price), using the most recent insider trade price on Form 4 (Oct 5, 2026), not a market close.

Scott Hanson

Chief Technology Officer, Director

n/a

−98K

n/a

Vesting, gifts, unvested awards and holding lines for Scott Hanson

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Scott Hanson are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
45,279	$8.12	Oct 1, 2028	$2.8M
83,558	$8.12	Feb 20, 2029	$5.1M
116,878	$12.60	May 25, 2031	$6.7M
71,428	$12.60	Jul 20, 2034	$4.1M

Estimate: options held × ($69.51 − strike price), using the most recent insider trade price on Form 4 (Oct 5, 2026), not a market close.

Timothy Chen

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. See the filing Sales and other transactions for Timothy Chen are complete.

Director

n/a

−71K

n/a

Vesting, gifts, unvested awards and holding lines for Timothy Chen

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Timothy Chen are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Joseph Tautges

Director

n/a

−7.8K

n/a

Vesting, gifts, unvested awards and holding lines for Joseph Tautges

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Joseph Tautges are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Sean Chen

President and COO

n/a

−100K

n/a

Vesting, gifts, unvested awards and holding lines for Sean Chen

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Sean Chen are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
1	$5.88	Nov 2, 2026	$64
134,423	$8.12	Feb 20, 2029	$8.3M
114,167	$12.60	May 25, 2031	$6.5M
93,979	$12.60	Jul 20, 2034	$5.3M

Estimate: options held × ($69.51 − strike price), using the most recent insider trade price on Form 4 (Oct 5, 2026), not a market close.

Jeffrey Winzeler

Chief Financial Officer

n/a

−31K

n/a

Vesting, gifts, unvested awards and holding lines for Jeffrey Winzeler

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Jeffrey Winzeler are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
104,953	$16.80	Jun 9, 2035	$5.5M

Estimate: options held × ($69.51 − strike price), using the most recent insider trade price on Form 4 (Oct 5, 2026), not a market close.

Ker Zhang

Director

n/a

−10K

n/a

Vesting, gifts, unvested awards and holding lines for Ker Zhang

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Ker Zhang are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
8,928	$6.44	Dec 16, 2027	$563K
3,571	$8.12	Feb 20, 2029	$219K
17,857	$12.60	Mar 2, 2031	$1.0M

Estimate: options held × ($69.51 − strike price), using the most recent insider trade price on Form 4 (Oct 5, 2026), not a market close.

Michele Connors

General Counsel

n/a

−811

n/a

Vesting, gifts, unvested awards and holding lines for Michele Connors

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Michele Connors are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Bernard Banks

Director

n/a

Vesting, gifts, unvested awards and holding lines for Bernard Banks

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Bernard Banks are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Holdings and share of stake for Ambiq Micro, Inc. are being verified, so no balances, unit counts or percentages are shown. Sales, proceeds, plan and tax status, titles and dates come straight from individual filings.

What explains the selling$37.5M of sales by plan status, purpose, seller and month

Officer and director open-market sales: $37.5M across 580,475 shares. Plan status and stated purpose are separate questions, and a sale can have both.

By plan status

Disclosed plan · $14.6M · 39%

61%

The lighter segment is sales with no plan disclosed in the filing ($22.9M), including tax-related sales outside a plan.

No plan disclosed · $20.8M

Sales with no 10b5-1 plan and no tax reference in the filing. $5.6M of it is Timothy Chen. No plan disclosed is a statement about the filing, not about why the sale happened. Largest such sale: Fumihide Esaka, May 14, 2026

Taxes

$2.6M of sales (6.8%) cite tax obligations in their footnotes, $404K of them also under a plan. Example: Jeffrey Winzeler, Oct 2, 2026

Seller	Shares sold	Proceeds	Under a disclosed plan	Share of total	Sales dates
Fumihide Esaka Chief Executive Officer, Director	262K	$16.4M	67%	44%	May 14, 2026 to Oct 2, 2026
Sean Chen President and COO	100K	$6.7M	41%	18%	May 15, 2026 to Oct 5, 2026
Scott Hanson Chief Technology Officer, Director	98K	$5.8M	15%	15%	Jan 26, 2026 to Oct 2, 2026
Timothy Chen Director	71K	$5.6M	0%	15%	May 27, 2026 to May 27, 2026
Jeffrey Winzeler Chief Financial Officer	31K	$2.2M	0%	6%	May 14, 2026 to Oct 2, 2026
Ker Zhang Director	10K	$645K	0%	2%	Sep 4, 2026 to Sep 11, 2026
Joseph Tautges Director	7.8K	$242K	0%	0.6%	Jan 26, 2026 to Jan 26, 2026
Michele Connors General Counsel	811	$21K	0%	0.1%	Apr 2, 2026 to Apr 2, 2026

Sales by month

Month	Sale proceeds	Disclosed plan	To cover taxes	No plan disclosed
Oct 2025	$0	$0	$0	$0
Nov 2025	$0	$0	$0	$0
Dec 2025	$0	$0	$0	$0
Jan 2026	$552K	$0	$0	$552K
Feb 2026	$0	$0	$0	$0
Mar 2026	$0	$0	$0	$0
Apr 2026	$21K	$0	$21K	$0
May 2026	$16.3M	$0	$0	$16.3M
Jun 2026	$0	$0	$0	$0
Jul 2026	$0	$0	$0	$0
Aug 2026	$7.4M	$4.1M	$0	$3.3M
Sep 2026	$10.2M	$9.5M	$0	$645K
Oct 2026	$3.1M	$952K	$2.1M	$0

Known gaps and uncertainty10 officers and directors not confirmed

Holdings and share of stake are being verified. Balances, unit counts and every share-of-stake figure for Ambiq Micro, Inc. are held back until that check is finished. Sales, proceeds, plan and tax status, titles and dates come straight from individual filings and are complete.

External context: we only cite outside events when a documented connection exists. None is shown for this period.

Sources and methodology63 filings on record, 45 filed in the 12-month period, and how we read them

All 63 Forms 3, 4 and 5 on record for Ambiq Micro, Inc. (SEC CIK 1500412), filed from Jul 29, 2025 to Oct 6, 2026; 45 of them were filed in the 12 months this page covers, retrieved from SEC EDGAR on Oct 16, 2026. Prices are the ones reported in each filing, often weighted averages.

Holdings. Each holding line (a share class plus an owner, such as a trust or LLC) carries its last reported balance forward. Entities first reported during the period start at zero, so transfers between an insider's own trusts don't count as selling. Lines not reported for three years or more are listed separately and left out of totals.

Sales. A sale counts as under a 10b5-1 plan if its footnote cites one or the filing's Rule 10b5-1 box is checked, and as tax-related if its footnote cites tax obligations or sell-to-cover. Shares withheld by the company for taxes are listed separately. Sales with neither attribute are labeled "no plan disclosed".

Full methodology

Spotted something wrong on this page? Report an error. We check every report against the SEC filing and list what we fix in the corrections log.

Ambiq Micro, Inc. insiders sold $37.5M in the past 12 months. How much of their stake is that?

What stands out

Who sold, and how much of their stake

Selling by month

Recent activity

Outside holders, reported separately

Common questions

Is the Ambiq Micro, Inc. CEO selling stock?

Why are Ambiq Micro, Inc. insiders selling?

Are any Ambiq Micro, Inc. insiders buying?

The evidence

No plan disclosed · $20.8M

Taxes

Sales by month