$AMPX

$8.36 +$0.18 (2.14%) Live

$AMPX Overview Financial Statements SEC Filings Executives News Red Flags Capital Raising Ownership Insider Transactions Congressional Trades

Ownership

13F as of Q2 2026 · 146.1M shares outstanding

Who owns AMPX?

By type of holder

Institutions 65.5% Insiders 7.5% Everyone else 27.1%

Concentration Top 10 holders own 31.5%

BlackRock, Inc. 7.8% · Vanguard Capital Management LLC 3.8%

Institutional ownership

65.5%

+7.8 pts vs last qtr

Institutional holders

258

+15 vs last qtr

Net shares bought

+11.5M

by institutions in Q2 2026

New / sold out

63 / 48

positions opened vs closed

How is ownership changing?

Institutions, last 8 quarters

Biggest buyers in Q2 2026

Jupiter Asset Management LTD NEW +2.1M
BlackRock, Inc. +2.1M

Biggest sellers in Q2 2026

Driehaus Capital Management LLC −2.4M
Massachusetts Financial Services Co /ma/ −1.5M

Who is planning to sell?

Notices of proposed sale, last 12 months

$87.2M

27 notices from 9 people

Shares covered

6.5M

4.44% of the company

Arranged in advance

75%

of the value is under a 10b5-1 plan

Under a 10b5-1 plan No plan

Largest proposed sellers

Kang Sun Director $57.5M
Stefan Constantin Ionel Officer $11.1M

Every notice on Red Flags →

A Form 144 is notice of a planned sale, not the sale itself. What insiders actually sold is on Insider Transactions.

Is your stake being diluted?

Diluted share count, FY2021–FY2025

+89.5%

+17.33% a year

Each share's claim on the business

−47.2%

shrank without buying or selling a share

Spent on buybacks vs paid in stock

— vs $23.8M

over 5 fiscal years

Diluted shares, split-adjusted

Buybacks Stock-based comp

How patient are the owners?

Institutional shares by how long they've been held

5+ years0% 3–5 years44% 1–3 years25% Under 1 year31%

Quarterly turnover

27.8%

of institutional shares changed hands

Top 10 managers, median time held

3.5 years

Super Investors

Investment managers reporting AMPX on Form 13F

Holder	Shares	% of company	Change vs last qtr	Held since	% of their book
B BlackRock, Inc.	11.3M	7.76%	+2.1M (+22.9%)	2022	0.0%
Shares held by quarter Peak holding11.3M (Q2'26) Change over 8 quarters+10.6M Share of the company7.760% BlackRock, Inc.'s full portfolio →
VC Vanguard Capital Management LLC	5.6M	3.81%	+654.1K (+13.3%)	2022	0.0%
Shares held by quarter Peak holding5.6M (Q2'26) Change over 8 quarters+5.6M Share of the company3.810% Vanguard Capital Management LLC's full portfolio →

BlackRock, Inc.

11.3M

% of company

7.76%

Change vs last qtr

+2.1M (+22.9%)

Held since

2022

Vanguard Capital Management LLC

5.6M

% of company

3.81%

Change vs last qtr

+654.1K (+13.3%)

Held since

2022

28 more super investors behind a free account

See every manager holding Amprius Technologies Inc, how their position has changed, and how long they've held it.

Institutional Funds

Mutual funds and ETFs reporting AMPX on Form N-PORT; together they hold 20.8% of the company

Fund	Position value	Shares	% of company	% of the fund	As of
VT Vanguard Total Stock Market Index Fund Vanguard Index Funds	$53M	3.8M	2.62%	0.00%	June 30, 2026
IR iShares Russell 2000 ETF iShares Trust	$49.6M	3.6M	2.45%	0.06%	June 30, 2026

Vanguard Total Stock Market Index Fund

Vanguard Index Funds

Position value

$53M

% of company

2.62%

% of the fund

0.00%

As of

June 30, 2026

iShares Russell 2000 ETF

iShares Trust

Position value

$49.6M

% of company

2.45%

% of the fund

0.06%

As of

June 30, 2026

23 more funds behind a free account

See every fund holding Amprius Technologies Inc and how much of the fund the position is.

Insiders and 5%+ holders

From Forms 3/4/5 and Schedules 13D/G

Holder	Shares	% of company	Change vs last qtr	8 quarters	Held since	% of their book
HW HSIEH Wen Hsuan Insider	4.1M	2.80%	—	—	—	—
Insider holdings come from Form 3/4/5 filings, which are not quarterly. Share of the company2.800% HSIEH Wen Hsuan's insider activity →
BJ Bornstein Jonathan Insider	1.5M	1.02%	—	—	—	—
Insider holdings come from Form 3/4/5 filings, which are not quarterly. Share of the company1.020% Bornstein Jonathan's insider activity →

HSIEH Wen Hsuan

Insider

4.1M

% of company

2.80%

Change vs last qtr

—

Held since

—

Bornstein Jonathan

Insider

1.5M

% of company

1.02%

Change vs last qtr

—

Held since

—

9 more holders behind a free account

See every insider and 5%+ holder of Amprius Technologies Inc.

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