AMPX Amprius Technologies, Inc.
Executive Summary
Ten institutional investors added a net $213.8M in Amprius Technologies (AMPX) during Q3 2025, overwhelmingly from mega-passive index funds, while two funds near-exited. The passive-dominated cluster suggests mechanical index-related buying rather than a strong active conviction thesis.
Key Financial Metrics
Institutional Positions
Net institutional flow: $208.3M
▲ Buyers (10)
| Institution | Action | Change | Position Value | Value Δ |
|---|---|---|---|---|
| Vanguard | ADD | +37% | $68.5M | $48.5M |
| BlackRock | ADD | +41.5% | $78.4M | $56.2M |
| State Street | ADD | +86.1% | $23.0M | $18.1M |
| Citadel | DOUBLED | +796.4% | $26.4M | $25.2M |
▼ Sellers (2)
| Institution | Action | Change | Prev Value | Value Δ |
|---|---|---|---|---|
| Renaissance Technologies | NEAR_EXIT | -99.1% | $5.7M | -$5.5M |
Actionable Insight
The cluster is dominated by passive funds, likely reflecting AMPX's inclusion in a major index or significant market-cap growth triggering automatic rebalancing. Citadel's large active bet adds some conviction, but the historical underperformance of similar cluster signals on AMPX (T+20 alpha -10.7%) warrants caution. Monitor for next 13F to see if these positions were maintained or reversed.
Key Facts
- 10 buyers added $213.8M net; 2 sellers reduced by $5.5M.
- Buyers include Vanguard (+$48.5M), BlackRock (+$56.2M), State Street (+$18.1M), and Citadel (+$25.2M, +796% shares).
- Only two sellers: T. Rowe Price (near-exit) and Renaissance Technologies (near-exit, -99% shares).
- 8 of 10 buyers are mega-passive index/ETF managers, reducing the signal's active conviction.
Financial Impact
Net institutional accumulation of $208.3M in Q3 2025, representing approximately 9% of AMPX's $2.3B market cap.
Risk Factors
- Passive buying may be mechanical and reversed on subsequent rebalancing.
- Renaissance Technologies near-exit signals potential fundamental concern from a sophisticated quant fund.
- Historical cluster signals on this ticker have underperformed market at T+20.
Market Snapshot
Documents Analyzed
This report is based on 1 institutional 13F filing from SEC EDGAR.
| Document | Accession Number |
|---|---|
| INST-CLUSTER Data (Synthetic) | inst-cluster-AMPX-2025-Q3 |
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
|
Jun 11, 2026
1d ago
|
Insider Cluster
| $17.13 awaiting T+5 | awaiting T+5 | — | — |
|
Jun 11, 2026
1d ago
|
Institutional Cluster
| $16.45 awaiting T+5 | awaiting T+5 | — | — |
|
Jun 8, 2026
4d ago
|
144
| $4.84 awaiting T+5 | awaiting T+5 | — | — |
|
May 28, 2026
15d ago
|
144
| — | awaiting T+5 | — | — |
|
May 28, 2026
15d ago
|
Insider Cluster
| $20.28 $21.74 | ▼ −7.20% | ▼ −7.49% | — |
|
May 28, 2026
15d ago
|
Insider Cluster
| $20.28 $19.69 | ▲ +2.91% | ▲ +0.39% | — |
|
May 26, 2026
17d ago
|
Insider Cluster
| $17.16 $22.91 | ▼ −33.51% | ▼ −32.30% | — |
|
May 26, 2026
17d ago
|
144
| — | awaiting T+5 | — | — |
|
May 26, 2026
17d ago
|
Insider Cluster
| $17.16 $22.91 | ▲ +33.51% | ▲ +32.30% | — |
|
Apr 21, 2026
7w ago
|
8-K
| — | awaiting T+5 | — | — |
US Market Status
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