The cluster is dominated by passive funds, likely reflecting AMPX's inclusion in a major index or significant market-cap growth triggering automatic rebalancing. Monitor for next 13F to see if these positions were maintained or reversed.
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 |
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.
Market Snapshot
Investment Themes
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 | ||||
|---|---|---|---|---|---|
Oct 9, 2026 17d ago | S-3ASR | $8.87 | awaiting T+60 | — | — |
Sep 25, 2026 4w ago | 8-K | $9.60 | awaiting T+60 | — | — |
Aug 25, 2026 8w ago | Insider Cluster | $10.20 | awaiting T+60 | — | — |
Aug 13, 2026 10w ago | 8-K | $12.51 | awaiting T+60 | — | — |
Aug 1, 2026 12w ago | Institutional Cluster | $10.12 | awaiting T+60 | — | — |
Jun 11, 2026 19w ago | Insider Cluster | $16.31 $10.39 | ▼ −36.30% | ▼ −39.56% | — |
Jun 11, 2026 19w ago | Institutional Cluster | $17.10 $9.89 | ▼ −42.16% | ▼ −46.56% | — |
Jun 8, 2026 20w ago | 144 | $4.84 | awaiting T+60 | — | — |
May 28, 2026 21w ago | 144 | — | awaiting T+60 | — | — |
May 28, 2026 21w ago | Insider Cluster | $20.28 $9.86 | ▲ +51.38% | ▲ +52.56% | — |
US Market Status
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