AMPX Amprius Technologies, Inc.
Price Chart
Executive Summary
Three Amprius insiders — the CEO, CTO, and a director — collectively sold $2.33M in open-market shares on May 21, 2026, all at ~$14.79. This is the largest insider selling cluster in the trailing 30 days ($2.33M vs. $2.3M prior), representing ~0.1% of the $2.3B market cap. While the dollar amount is modest relative to market cap, the simultaneous sale by the CEO and CTO — the two most operationally informed executives — on the same day at the same price raises a caution flag, especially given the stock's recent run and the 93% bullish analyst consensus.
Key Financial Metrics
Actionable Insight
The simultaneous CEO/CTO sale at identical prices suggests a coordinated exit or a shared response to a blackout-window opening. Monitor for an upcoming earnings release, material agreement, or offering — the cross-filing actuarial verdicts flag cluster-insider-trades + cluster-offering-context and cluster-insider-trades + cluster-press-context as amplifiers. If the stock breaks below $14.50, the cluster may signal near-term weakness. Conversely, if no negative catalyst emerges within 10 trading days, the selling may be purely liquidity-driven.
Key Facts
- CEO Stepien Thomas M sold 60,702 shares for $898K on May 21, 2026.
- CTO Stefan Constantin Ionel sold 28,812 shares for $426K on May 21, 2026.
- Director Sun Kang sold 67,796 shares for $1.00M on May 21, 2026.
- Total cluster value: $2.33M, or ~0.1% of AMPX's $2.3B market cap.
- All three sales were open-market (code S) at the same price of $14.7884.
- Prior 30-day insider activity: 3 sells totaling $2.3M — this cluster nearly doubles that volume in a single day.
- Historical calibration shows cluster sells at AMPX have not been reliably predictive (avg T+20 alpha -8.27% across prior reports), but the C-suite concentration here is notable.
Financial Impact
Total insider selling of $2.33M, representing ~0.1% of market cap. No direct financial impact to the company.
Risk Factors
- Insiders may be reacting to non-public negative information (e.g., a pending offering, weak Q2 pre-announcement, or customer loss).
- The stock has a 93% bullish analyst consensus — a contrarian insider sell cluster could trigger a sharp re-rating if negative news follows.
- Historical T+20 alpha on AMPX insider reports is negative (-8.27%), suggesting the market has previously overreacted to insider signals at this name.
Market Snapshot
Documents Analyzed
This report is based on 1 SEC document filed with EDGAR.
| Document | Accession Number |
|---|---|
| CLUSTER Data (Synthetic) | cluster-AMPX-1779838339705 |
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
|
May 28, 2026
12d ago
|
Insider Cluster
| $20.28 $21.74 | ▼ −7.20% | ▼ −7.49% | $18.83 (+7.15%) |
|
May 28, 2026
12d ago
|
Insider Cluster
| $20.28 $19.69 | ▲ +2.91% | ▲ +0.39% | $18.83 (+7.15%) |
|
May 26, 2026
14d ago
|
Insider Cluster
| $17.16 $22.91 | ▼ −33.51% | ▼ −32.30% | $18.83 (−9.73%) |
|
May 26, 2026
14d ago
|
Insider Cluster
| $17.16 $22.91 | ▲ +33.51% | ▲ +32.30% | $18.83 (+9.73%) |
|
Mar 12, 2026
12w ago
|
Insider Cluster
| $18.29 $19.11 | ▼ −4.48% | ▼ −5.46% | $18.83 (−2.95%) |
|
Mar 4, 2026
13w ago
|
8-K
| $14.89 $18.29 | ▲ +22.83% | ▲ +25.07% | $18.83 (+26.46%) |
|
Feb 23, 2026
15w ago
|
Insider Cluster
| $10.20 $11.59 | ▼ −13.63% | ▼ −13.01% | $18.83 (−84.61%) |
US Market Status
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