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Data sources

Public disclosures only. Scores flag unusual patterns and are not evidence of wrongdoing. Not investment advice.

RH CHAIN…
OverviewDaily BriefLiveCongressCorporate InsidersGovernment MoneyPolitical InfluenceInstitutionsWashington NetworkFollow the PowerDisclosure ClockAI InvestigatorWatchlistConvergenceINSIDER AlphaSignal ledgerHistorical ReplayRobinhood ChainProofTradingTokenProMethodologyMatch reviewLaunch readiness
01Overview02Daily Brief03Live04Congress05Corporate Insiders06Government Money07Political Influence08Institutions09Washington Network10Follow the Power11Disclosure Clock12AI Investigator13Watchlist
ConvergenceINSIDER AlphaSignal ledgerHistorical ReplayRobinhood ChainProofTradingTokenProMethodologyMatch reviewLaunch readiness
OverviewDaily BriefLiveCongressCorporate InsidersGovernment MoneyPolitical InfluenceInstitutionsWashington NetworkFollow the PowerDisclosure ClockAI InvestigatorWatchlistConvergenceINSIDER AlphaSignal ledgerHistorical ReplayRobinhood ChainProofTradingTokenProMethodologyMatch reviewLaunch readiness
Data sources
SEC FORM 415m ago
HOUSE PTR15m ago
SEC 13F15m ago
ROBINHOOD CHAIN15m ago
SEC FORM 4/Open-market saleVerified data

Stepien Thomas M sold AMPX

Director, Chief Executive Officer · Amprius Technologies, Inc. · Common stock

Side
SELL
Value
$898K
Shares
60.7K
Price
$14.79
Executed
May 21, 2026
Disclosed
May 26, 2026
Disclosure timeline5 days from execution to publication · legal deadline 2 business days
May 21 executedMay 26, 2026 disclosed

AMPX · daily

Yahoo Finance chart API
▲Execution▼Disclosure●Material company filing●Other disclosed buy●Other disclosed sellUnofficial public endpoint; daily OHLCV, split-adjusted. Replace with a licensed feed for production.

Insider Score

Experimental signal
42/ 100 · ELEVATED
Methodology →
  • Transaction type+12 / 20

    Open-market sale

  • Relative size+11 / 25

    $898K reported value · 8.0% of prior position

  • Filing timing+6 / 15

    Disclosed 3 business days after execution (deadline: 2)

  • Historical behavior+8 / 15

    First recorded trade by this actor in this security

  • Frequency & clustering+5 / 15

    1 other actor traded the same direction within 14 days

  • Market events0 / 10

    No material company filing within 60 days after the trade

    • The Insider Score measures how far a disclosure deviates from normal filing patterns. A high score is a prompt for research, not evidence of illegal insider trading.

    Other disclosed activity · AMPX

    ScoreActorSecuritySideValueExecutedDisclosedLagSourceEvidence
    25
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Open-market sale
    		SELL$243K
    23.5K sh
    		Aug 21, 2026Aug 25, 2026
    traded Aug 21, 2026
    		+4dSEC FORM 4

    Evidence

    25
    SI
    Stefan Constantin IonelChief Technology Officer
    AMPXAmprius Technologies, Inc.
    Open-market sale
    		SELL$307K
    29.7K sh
    		Aug 21, 2026Aug 25, 2026
    traded Aug 21, 2026
    		+4dSEC FORM 4

    Evidence

    25
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Open-market sale
    		SELL$80K
    8,000 sh
    		Aug 24, 2026Aug 25, 2026
    traded Aug 24, 2026
    		+1dSEC FORM 4

    Evidence

    8
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Gift
    		G—
    346 sh
    		Aug 25, 2026Aug 25, 2026
    traded Aug 25, 2026
    		+0dSEC FORM 4

    Evidence

    5
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Grant or award
    		A—
    346 sh
    		Aug 25, 2026Aug 25, 2026
    traded Aug 25, 2026
    		+0dSEC FORM 4

    Evidence

    8
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Gift
    		G—
    5,000 sh
    		Aug 25, 2026Aug 25, 2026
    traded Aug 25, 2026
    		+0dSEC FORM 4

    Evidence

    8
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Gift
    		G—
    5,000 sh
    		Aug 25, 2026Aug 25, 2026
    traded Aug 25, 2026
    		+0dSEC FORM 4

    Evidence

    8
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Gift
    		G—
    5,000 sh
    		Aug 25, 2026Aug 25, 2026
    traded Aug 25, 2026
    		+0dSEC FORM 4

    Evidence

    12
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Gift
    		G—
    36.9K sh
    		Jun 4, 2026Jun 5, 2026
    traded Jun 4, 2026
    		+1dSEC FORM 4

    Evidence

    22
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Open-market sale
    		SELL$42K
    2,000 sh
    		Jun 4, 2026Jun 5, 2026
    traded Jun 4, 2026
    		+1dSEC FORM 4

    Evidence

    8
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Gift
    		G—
    36.9K sh
    		Jun 4, 2026Jun 5, 2026
    traded Jun 4, 2026
    		+1dSEC FORM 4

    Evidence

    8
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Gift
    		G—
    30.4K sh
    		Jun 4, 2026Jun 5, 2026
    traded Jun 4, 2026
    		+1dSEC FORM 4

    Evidence

    25
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Open-market sale
    		SELL$75K
    4,375 sh
    		May 27, 2026May 28, 2026
    traded May 27, 2026
    		+1dSEC FORM 4

    Evidence

    22
    SI
    Stefan Constantin IonelChief Technology Officer
    AMPXAmprius Technologies, Inc.
    Open-market sale
    		SELL$55K
    3,208 sh
    		May 27, 2026May 28, 2026
    traded May 27, 2026
    		+1dSEC FORM 4

    Evidence

    31
    SI
    Stefan Constantin IonelChief Technology Officer
    AMPXAmprius Technologies, Inc.
    Open-market sale
    		SELL$426K
    28.8K sh
    		May 21, 2026May 26, 2026
    traded May 21, 2026
    		+5dSEC FORM 4

    Evidence

    17
    SM
    Stepien Thomas MDirector, Chief Executive Officer
    AMPXAmprius Technologies, Inc.
    Grant or award
    		A—
    150.0K sh
    		Mar 4, 2026Mar 6, 2026
    traded Mar 4, 2026
    		+2dSEC FORM 4

    Evidence

    6
    SI
    Stefan Constantin IonelChief Technology Officer
    AMPXAmprius Technologies, Inc.
    Grant or award
    		A—
    110.0K sh
    		Mar 4, 2026Mar 6, 2026
    traded Mar 4, 2026
    		+2dSEC FORM 4

    Evidence

    21
    RC
    Rodriguez Ricardo C.Chief Financial Officer
    AMPXAmprius Technologies, Inc.
    Grant or award
    		A—
    150.0K sh
    		Mar 4, 2026Mar 6, 2026
    traded Mar 4, 2026
    		+2dSEC FORM 4

    Evidence

    27
    SI
    Stefan Constantin IonelChief Technology Officer
    AMPXAmprius Technologies, Inc.
    Open-market sale
    		SELL$476K
    39.7K sh
    		Jan 28, 2026Jan 30, 2026
    traded Jan 28, 2026
    		+2dSEC FORM 4

    Evidence

    5
    SI
    Stefan Constantin IonelChief Technology Officer
    AMPXAmprius Technologies, Inc.
    Option exercise
    		M$55.8
    90 sh
    		Jan 28, 2026Jan 30, 2026
    traded Jan 28, 2026
    		+2dSEC FORM 4

    Evidence

    Evidence

    Verified data

    Read directly from the primary public document; every field below is as reported by the filer.

    Source

    Document
    SEC Form 4
    Publisher
    U.S. Securities and Exchange Commission (EDGAR)
    Document ID
    0002067233-26-000008
    Machine-readable
    Structured copy

    Timestamps

    Event (reported)
    May 21, 2026
    Published
    May 26, 2026
    Ingested by INSIDER
    Nov 5, 03:56 UTC
    Last re-read
    Nov 5, 03:56 UTC

    Extracted facts

    Filer
    Stepien Thomas M
    Role
    Director, Chief Executive Officer
    Transaction
    Open-market saleAs filed: “S”
    Asset
    Amprius Technologies, Inc.
    Ticker
    AMPX
    Shares
    60.7K
    Price per share
    $14.79
    Value
    $897,685
    Execution date (reported)
    May 21, 2026
    Owned after transaction
    699.3K shares
    Days from execution to publication
    5

    Calculation

    Value = shares × reported price per share

    • Shares: 60.7K
    • Price: $14.7884

    = $897,685

    What this establishes

    Stepien Thomas M filed this Form 4 reporting a open-market sale of AMPX on May 21, 2026. It became public on May 26, 2026. The filing establishes the reported transaction and the filer's stated role. It does not establish why the trade was made or what the filer knew.

    Extraction

    Method
    Form 4 XML
    Confidence
    1.00
    Director, Chief Executive Officer
    Stepien Thomas Mcik:0002067233
    Issuer
    Amprius Technologies, Inc.cik:0001899287

    Revision history · 0

    No field has changed since this record was first ingested.

    Company events

    No records

    No material filings recorded for this issuer.