Who owns QUANTUM CORP /DE/?
Prices and market caps: Cboe delayed data, at least 15 minutes delayed. Not real-time. Fundamentals from company filings.
Institutional ownership of QMCO from SEC Form 13F filings across 61 reporting managers. All positions are from one synchronized reporting period — 2026-06-30 books, filed up to 45 days after quarter end — so every row is comparable.
As of the 2026-06-30 reporting period, 61 institutions disclosed 14.5M shares of QUANTUM CORP /DE/ worth $158.1M — about 65.7% of shares outstanding; the largest disclosed holder is Alyeska Investment Group, L.P.. Source: SEC Form 13F filings, parsed by EvidInvest.
61
13F holders
$158.1M
value, 2026 filers
65.7%
of shares outstanding (14.5M sh)
32
new positions (2026 filers)
Top institutional holders
ordered by shares owned · positions as of 2026-06-30 · % of fund = share of the manager's own book · % of co. = share of QMCO's shares outstanding
| # | Manager | Shares | Value | % of fund | % of co. | Δ shares QoQ |
|---|---|---|---|---|---|---|
| 1 | Alyeska Investment Group, L.P.NEW | 2.7M | $29.2M | 0.1% | 12.1% | new |
| 2 | Two Seas Capital LPNEW | 2.5M | $27.4M | 0.5% | 11.3% | new |
| 3 | OAKTREE CAPITAL MANAGEMENT LPNEW | 2.0M | $22.1M | 0.3% | 9.1% | new |
| 4 | NEUBERGER BERMAN GROUP LLCNEW | 1.2M | $12.8M | 0.0% | 5.3% | new |
| 5 | ASHFORD CAPITAL MANAGEMENT INCNEW | 1.0M | $10.6M | 1.1% | 4.7% | new |
| 6 | Portolan Capital Management, LLCNEW | 1.0M | $11.2M | 0.4% | 4.6% | new |
| 7 | MARSHALL WACE, LLP | 713,075 | $7.8M | 0.0% | 3.2% | +1800.1% |
| 8 | VANGUARD CAPITAL MANAGEMENT LLC | 605,541 | $6.7M | 0.0% | 2.8% | +12.3% |
| 9 | Manatuck Hill Partners, LLCNEW | 350,000 | $3.9M | 1.3% | 1.6% | new |
| 10 | BlackRock, Inc. | 273,030 | $3.0M | 0.0% | 1.2% | +25.5% |
| 11 | Cinctive Capital Management LPNEW | 182,769 | $2.0M | 0.1% | 0.8% | new |
| 12 | BANK OF AMERICA CORP /DE/ | 170,130 | $1.9M | 0.0% | 0.8% | +730.5% |
| 13 | GEODE CAPITAL MANAGEMENT, LLC | 164,600 | $1.8M | 0.0% | 0.7% | +3.4% |
| 14 | RENAISSANCE TECHNOLOGIES LLCNEW | 154,516 | $1.7M | 0.0% | 0.7% | new |
| 15 | SONA ASSET MANAGEMENT (US) LLC | 150,000 | $1.6M | 0.0% | 0.7% | +114.0% |
| 16 | Walleye Capital LLCNEW | 120,044 | $1.3M | 0.0% | 0.5% | new |
| 17 | RAYMOND JAMES FINANCIAL INCNEW | 103,836 | $1.1M | 0.0% | 0.5% | new |
| 18 | Centiva Capital, LPNEW | 100,000 | $1.1M | 0.0% | 0.5% | new |
| 19 | KKM Financial LLCNEW | 90,274 | $960,515 | 0.1% | 0.4% | new |
| 20 | VANGUARD FIDUCIARY TRUST CO | 89,125 | $980,375 | 0.0% | 0.4% | +11.0% |
| 21 | Qube Research & Technologies LtdNEW | 80,977 | $890,747 | 0.0% | 0.4% | new |
| 22 | STATE STREET CORP | 75,914 | $835,054 | 0.0% | 0.3% | +4.3% |
| 23 | Cygnus Capital Advisors, LLC | 74,323 | $818,000 | 0.6% | 0.3% | -40.1% |
| 24 | SUSQUEHANNA INTERNATIONAL GROUP, LLPNEW | 69,775 | $767,525 | 0.0% | 0.3% | new |
| 25 | Man Group plcNEW | 68,593 | $754,523 | 0.0% | 0.3% | new |
Source: SEC Form 13F-HR filings (institutional managers over $100M in US-listed positions). 13Fs disclose long positions only, up to 45 days after quarter end; each manager's latest filed quarter is shown per row and dollar values are the manager's filed marks. Aggregates labeled "2026 filers" count only managers whose latest book is a 2026 quarter. Related: valuation · options positioning · supply chain. Research, not investment advice.