Quantum Corporation (QMCO) ownership: Top institutional holder: VANGUARD GROUP INC ($4.03M). Insider activity: Net Seller (0 buys, 5 sells). 1 recent congressional STOCK Act disclosures. SEC EDGAR first-party data.
| Holder | Shares | Market Value | Reported |
|---|---|---|---|
| VANGUARD GROUP INC | 625538.00 | $4.03M | 2025-12-31 |
| Portolan Capital Management, LLC | 477214.00 | $3.08M | 2025-12-31 |
| VANGUARD CAPITAL MANAGEMENT LLC | 539275.00 | $2.56M | 2026-03-31 |
| BlackRock, Inc. | 217532.00 | $1.03M | 2026-03-31 |
| GEODE CAPITAL MANAGEMENT, LLC | 159179.00 | $756472.00 | 2026-03-31 |
| Cygnus Capital Advisors, LLC | 124086.00 | $590000.00 | 2026-03-31 |
| UBS Group AG | 99068.00 | $470573.00 | 2026-03-31 |
| VANGUARD FIDUCIARY TRUST CO | 80263.00 | $381249.00 | 2026-03-31 |
| Insider | Transaction | Value | Date |
|---|---|---|---|
| Sell | null | 2026-04-02 | |
| Sell | null | 2026-04-01 | |
| Sell | null | 2026-04-01 | |
| Sell | null | 2026-04-01 | |
| Sell | null | 2026-03-04 |
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Institutional data from SEC Form 13F. Insider data from SEC Form 4. Congressional data from STOCK Act disclosures. Not personalized investment advice.