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AMPX · Amprius Technologies, Inc.
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AMPX Amprius Technologies (AMPX) Insider Trading, Ownership & Congress Trades

Semiconductors & Electronics · Miscellaneous electrical machinery, equipment & supplies · CIK 0001899287
Quote by TradingView
Form 144 · 4
Insider buyers, 180 days
0
House members buying, 1 year
0
STOCK Act, US House only, disclosed up to 45 days after the trade
Funds added, last quarter
172
13F, latest reported quarter

What the filings say about AMPX

Insiders, 180 days
-$6.3M net sold
4 sellers · 0% of sales under a 10b5-1 plan
Planned sales (Form 144), 90 days
$1.3M
4 notices

Amprius Technologies insider trades (Form 4)

Form 4 buys and sells (codes P and S). Grants, option exercises and conversions excluded.

Over the last 180 days, Amprius Technologies, Inc. insiders sold a net $6.3M of stock across 122 Form 4 purchases and sales, with no insider buying. Source: SEC Form 4 filings, as of 2026-10-28.

Insider
Filed
Shares
Value
Since filing
Stepien Thomas M
Chief Executive Officer
SELL
2026-08-25 SECtraded 2026-08-24
8,000
$80.2K
-12.9%
Context
  • 4 earlier Form 4 trades (code P or S) here by this insider (4 sales), the last on Aug 21, 2026.
  • The trade is 1.3% of the 594,096 shares held after it.
  • 2 other insiders sold within 30 days.
  • 172 funds added in the 13F quarter to Jun 30, 2026.
Insider activity: Chief Executive Officer Stepien Thomas M sold about $80.2K of AMPX on Aug 24, 2026; 2 other insiders sold within 30 days and 172 funds added in the latest 13F quarter.
Stepien Thomas M
Chief Executive Officer
SELL
2026-08-25 SECtraded 2026-08-21
23,529
$243.3K
-12.9%
Context
  • 3 earlier Form 4 trades (code P or S) here by this insider (3 sales), the last on Jun 4, 2026.
  • The trade is 3.9% of the 602,096 shares held after it.
  • 2 other insiders sold within 30 days.
  • 172 funds added in the 13F quarter to Jun 30, 2026.
Insider activity: Chief Executive Officer Stepien Thomas M sold about $243.3K of AMPX on Aug 21, 2026; 2 other insiders sold within 30 days and 172 funds added in the latest 13F quarter.
Stefan Constantin Ionel
Chief Technology Officer
SELL
2026-08-25 SECtraded 2026-08-21
29,681
$306.9K
-12.9%
Context
  • 18 earlier Form 4 trades (code P or S) here by this insider (18 sales), the last on May 27, 2026.
  • The trade is 3.8% of the 771,629 shares held after it.
  • 2 other insiders sold within 30 days.
  • 172 funds added in the 13F quarter to Jun 30, 2026.
Insider activity: Chief Technology Officer Stefan Constantin Ionel sold about $306.9K of AMPX on Aug 21, 2026; 2 other insiders sold within 30 days and 172 funds added in the latest 13F quarter.
Sun Kang
Director
SELL
2026-08-25 SECtraded 2026-08-21
62,101
$642.2K
-12.9%
Context
  • 19 earlier Form 4 trades (code P or S) here by this insider (19 sales), the last on May 27, 2026.
  • The trade is 5.1% of the 1,218,397 shares held after it.
  • 2 other insiders sold within 30 days.
  • 172 funds added in the 13F quarter to Jun 30, 2026.
Insider activity: Director Sun Kang sold about $642.2K of AMPX on Aug 21, 2026; 2 other insiders sold within 30 days and 172 funds added in the latest 13F quarter.
DIXON DONALD R
Director
SELL
2026-06-16 SECtraded 2026-06-15
85,000
$1.5M
-40.8%
Context
  • 2 earlier Form 4 trades (code P or S) here by this insider (2 sales), the last on Jun 9, 2026.
  • The trade is 23.7% of the 359,380 shares held after it.
  • 3 other insiders sold within 30 days.
  • 172 funds added in the 13F quarter to Jun 30, 2026.
Insider activity: Director DIXON DONALD R sold about $1.5M of AMPX on Jun 15, 2026; 3 other insiders sold within 30 days and 172 funds added in the latest 13F quarter.
122 transactions on record
Since filing: total return from the first close after the filing to the latest close, dividend-adjusted. Not a forecast.
Context lines are counts over the filings above and returns from our own price history, never a price level. Not investment advice.
See all insider buying · insider selling
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Seven facts, ranked against the sector · Rank is not a forecast
Insiders
net -$6.3M over 180 days
-$1.3M over 90 days
below 52% of Semiconductors & Electronics
Congress
no House purchase disclosed in the last 12 months
Funds
172 funds bought in last quarter
more than 54% of Semiconductors & Electronics
Revenue
+205.1% year over year
more than 93% of Semiconductors & Electronics
Margin
-61.2% net margin
below 81% of Semiconductors & Electronics
Buybacks
no share repurchases reported
Short interest
15.9% of the float short (float per yahoo 2026-10-27) · 3.8 days to cover · settled 2026-10-15
more than 88% of Semiconductors & Electronics
What changed in the last 30 days
Nothing new filed in the last 30 days

Watch AMPX

A free account keeps a watchlist and can send one email a day when insiders, funds or Congress file on the names in it. No password and no card.

The year, with the filings on it
Total return over 12 months. Each marker is a filing; hover or tap one for the detail.
-23.8%12M
-35%+9%+53%+96%2025-102025-122026-022026-042026-062026-082026-10 2026-04-01 · Sun Kang sold $19.7M2025-11-17 · Sun Kang sold $10.6M2026-01-16 · Sun Kang sold $10.5M2026-01-22 · Stefan Constantin Ionel sold $5.9M2026-03-12 · HSIEH Wen Hsuan sold $5.2M2026-01-12 · Sun Kang sold $5.1M2026-04-01 · Sun Kang sold $4.2M2026-03-10 · Chu Steven sold $3.0M2026-03-23 · Sun Kang sold $2.9M2026-03-12 · HSIEH Wen Hsuan sold $2.4M2025-12-11 · Stefan Constantin Ionel sold $2.1M2026-03-12 · Chu Steven sold $1.9M2026-06-15 · DIXON DONALD R sold $1.5M2026-03-23 · Sun Kang sold $1.2M2026-05-21 · Sun Kang sold $1.0M2026-03-12 · Chu Steven sold $910.5K2026-05-21 · Stepien Thomas M sold $897.8K2026-01-21 · Stefan Constantin Ionel sold $879.4K2026-06-09 · DIXON DONALD R sold $765.2K2025-11-21 · Sun Kang sold $692.0K2026-08-21 · Sun Kang sold $642.2K2026-02-23 · Sun Kang sold $622.3K2026-01-20 · Sun Kang sold $476.3K2026-01-28 · Stefan Constantin Ionel sold $476.3K2026-05-21 · Stefan Constantin Ionel sold $426.1K2026-05-26 · DIXON DONALD R sold $320.3K2026-08-21 · Stefan Constantin Ionel sold $306.9K2026-02-23 · Stefan Constantin Ionel sold $257.7K2025-11-21 · Stefan Constantin Ionel sold $252.2K2026-08-21 · Stepien Thomas M sold $243.3K2026-03-12 · Chu Steven sold $103.1K2026-08-24 · Stepien Thomas M sold $80.2K2026-05-27 · Stepien Thomas M sold $75.2K2026-05-27 · Stefan Constantin Ionel sold $55.1K2026-06-04 · Stepien Thomas M sold $41.9K2026-01-23 · Stefan Constantin Ionel sold $19.2K2026-05-27 · Sun Kang sold $6.1K2026-08-25 · KANG SUN filed to sell $642.2K2026-08-25 · Constantin Ionel Stefan filed to sell $306.9K2026-08-25 · THOMAS M STEPIEN filed to sell $243.3K2026-08-24 · THOMAS M STEPIEN filed to sell $80.2K
Insider sellForm 144 (planned sale)
Indexed to 100, dividend-adjusted, not a price chart. When a name files heavily, the largest trades are drawn first.

Who owns AMPX: institutional holders (13F)

13F holdings, latest reported quarter
BlackRock, Inc.
11,335,092 sh
$157.1M
VANGUARD CAPITAL MANAGEMENT LLC
5,562,985 sh
$77.1M
MORGAN STANLEY
5,105,505 sh
$70.8M
TWO SIGMA INVESTMENTS, LP
4,318,630 sh
$59.9M
UBS Group AG
4,073,080 sh
$56.4M

Congress trades in AMPX

No Congress trades reported
No House member has disclosed a trade in this stock. See what Congress is buying.

Activist and 5% holders (13D/13G)

No 5%+ ownership filings
Nobody has filed for crossing 5%. That is a fact, not missing data.

AMPX planned insider sales (Form 144)

Notice of intent to sell, filed before any sale
KANG SUN
Filed 2026-08-25
$642.2K
Constantin Ionel Stefan
Filed 2026-08-25
$306.9K
THOMAS M STEPIEN
Filed 2026-08-25
$243.3K
THOMAS M STEPIEN
Filed 2026-08-24
$80.2K

AMPX mutual fund holders (N-PORT)

Funds ranked by the share of their own portfolio in this stock (N-PORT).
WisdomTree Physical AI, Humanoids and Drones Fund
$771.8K position · as of 2026-06-30
4.3%
AlphaCentric Robotics and Automation Fund
$693.0K position · as of 2026-06-30
2.6%
U.S. Global Technology and Aerospace & Defense ETF
$1.1M position · as of 2026-06-30
2.6%
ALPS Clean Energy ETF
$3.5M position · as of 2026-05-31
2.4%
Global X CleanTech ETF
$624.7K position · as of 2026-05-31
1.8%
Global X Autonomous & Electric Vehicles ETF
$8.2M position · as of 2026-05-31
1.7%
SEC N-PORT, monthly, about 60 days late · funds ≥ $10M · % is the share of the fund's own portfolio
Live price
Daily candles from TradingView, under their licence. No filings marked.
Why this name is on the desk
Insiders have filed to sell, before selling.
The record shows a net $6.3M sold by insiders over 180 days, 172 funds added last quarter, $1.3M in planned Form 144 sales. Each figure is a federal filing, dated the day it went public.
Backtest this pattern Open the screener
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AMPX financials

Revenue growth
+205.1%
XBRL, annual
Net margin
-61.2%
Ratios from the company's XBRL filings, latest filings
Revenue, TTM
$109.2M
four quarters, 2025-07-01 to 2026-06-30
Net margin, TTM
-33.4%
net income over revenue, 2025-07-01 to 2026-06-30
Free cash flow, TTM
-$58.4M
operating cash flow minus capex, 2025-07-01 to 2026-06-30
Debt to equity
n/a
no debt line filed
Cash flow to debt
n/a
no debt line filed
Return on equity
-36.1%
TTM net income over average of 2025-06-30 and 2026-06-30
Return on assets
-26.8%
TTM net income over average of 2025-06-30 and 2026-06-30
Return on invested capital
n/a
tax provision or pre-tax income not filed for the four quarters
Return on capital employed
-34.0%
operating income (EBIT proxy) over average of 2025-06-30 and 2026-06-30 minus current liabilities
P/E, trailing
n/a
trailing loss, a multiple of a loss is not meaningful
Enterprise value
n/a
no debt line filed
FCF yield
-4.5%
TTM free cash flow over market value at close 2026-10-27
PEG, trailing
n/a
trailing loss, a multiple of a loss is not meaningful
Price as of 2026-10-27. Hover or tap a tile for its yearly and quarterly history.
Method
TTM is four consecutive fiscal quarters; Q4 is the year minus nine months when not filed. Returns use the average of opening and closing balances. EBIT is approximated by operating income. PEG uses trailing EPS growth.
Fundamentals
Annual figures from XBRL filings. Pick a past date to see them as known then.
2025-122024-122023-122022-12
Revenue$73.0M$24.2M$9.1M$4.4M
Gross profit$8.3M-$18.3M-$14.7M-$5.7M
Operating income-$46.6M-$46.3M-$38.7M-$18.0M
Net income-$44.0M-$44.7M-$36.8M-$17.3M
EPS (diluted)-0.35-0.45-0.43-0.24
Operating cash flow-$31.1M-$33.4M-$25.6M-$13.9M
Cash$90.5M$55.2M$45.8M$69.7M
SEC XBRL, fiscal years, as known on 2026-10-28

AMPX Stock Sonar score 5/7 axes

Find similar shapesCompare

AMPX ranks highest on growth (82nd percentile) and institutional and government (39th), and lowest on profitability (20th), among Semiconductors & Electronics peers.

ProfitGrowthInsidersInstitutionsRisk
Profitability
20
Inputs
  • Return on equity-36.1% · 20 pct, sector of 154
  • Return on assets-26.8% · 19 pct, sector of 171
  • Return on invested capitaltax provision or pre-tax income not filed for the four quarters
  • Return on capital employed-34.0% · 19 pct, sector of 155
Growth
82
Inputs
  • Revenue growth, YoY+205.1% · 93 pct, sector of 194
  • Backlog growth, YoY+25.4% · 70 pct, sector of 51
Insider conviction
22
Inputs
  • Net Form 4 buying (codes P and S), 180d-$6.3M · 45 pct, sector of 146
  • Insider buyers, 180d0 · 0 pct, sector of 150
Institutional and government
39
Inputs
  • Funds adding, latest quarter172 · 54 pct, sector of 184
  • Congress net buyers, 365dno Congress trades in 365 days
  • Federal contracts, 180dno federal contracts in 180 days
  • Lobbying spend, 4 quarters$160K · 25 pct, sector of 53
Risk and compliance
34
Inputs
  • Short interest, % of float+15.9% · 15 pct, sector of 220
  • Recalls per $1B revenue, 3ynot measured for this sector, almost no peer has an event
  • EPA cases per $1B revenue, 5ynot measured for this sector, almost no peer has an event
  • New text in Risk Factors, latest 10-K+10.8% · 54 pct, sector of 152
2 not measured: Financial health, US patents
  • Financial health needs 1 of 2 inputs, 0 present: no debt line filed
  • US patents needs 1 of 2 inputs, 0 present: patent data not loaded yet

5 of 7 axes scored. Each is a percentile against sector peers (all companies when the sector is thin); higher is better. An unscored axis is unmeasured, not low. How it is scored

AMPX filings, in plain words

Are Amprius Technologies insiders buying or selling AMPX?

In the 180 days to 2026-10-28, Amprius Technologies insiders were net sellers, a net $6.3M across purchases and sales reported on Form 4, by 4 sellers.

Are there planned insider sales of AMPX?

Yes. 4 Form 144 notices of planned insider sales were filed in the 90 days to 2026-10-28, covering $1.3M of stock; the latest, by KANG SUN, was filed 2026-08-25.

Read the full summary

In the 180 days to 2026-10-28, Amprius Technologies insiders were net sellers of AMPX, a net $6.3M across purchases and sales reported on Form 4 by 4 sellers. None of the 14 insider sales was flagged as made under a Rule 10b5-1 plan. Insiders filed 4 Form 144 notices of intent to sell in the 90 days to 2026-10-28, covering $1.3M of stock. Each figure is counted from SEC and House filings as of 2026-10-28, dated the day the filing was made public.

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