Quantum Corporation
Ownership
Ownership Structure
Who owns Quantum Corporation (QMCO)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 86.6% of the shares are freely tradable; institutional investors hold 12.8%.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Alyeska Investment Group, L.P. | 6.73 | 2,653,928 | +0.0 | 06/30/2026 |
| Oaktree Capital Management LLC | 5.10 | 2,011,678 | +0.0 | 06/30/2026 |
| Neuberger Berman Group LLC | 2.95 | 1,163,315 | +0.0 | 06/30/2026 |
| Ashford Capital Management Inc | 2.64 | 1,039,200 | +0.0 | 06/30/2026 |
| Portolan Capital Management, LLC | 2.59 | 1,020,120 | +0.0 | 06/30/2026 |
| Marshall Wace Asset Management Ltd | 1.81 | 713,075 | +1,800.1 | 06/30/2026 |
| Vanguard Capital Management, LLC | 1.54 | 605,541 | +12.3 | 06/30/2026 |
| Manatuck Hill Partners LLC | 0.89 | 350,000 | +0.0 | 06/30/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Vanguard MStar Total Stk Mkt Idx Invest | 2.10 | 828,896 | +97.0 | 09/30/2026 |
| Neuberger Intrinsic Value I | 1.12 | 442,171 | -43.1 | 09/30/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Clancy James C | Chief Operating Officer | 163,000 | 2,982,900 $ | Oct 1, 2026 | direct |
| White Yue Zhou | Director | 53,139 | 972,444 $ | Oct 1, 2026 | direct |
| Jaworksi Don | Director | 51,675 | 945,653 $ | Oct 1, 2026 | direct |
| Patel Hiral | Chief Accounting Officer | 50,000 | 915,000 $ | Oct 1, 2026 | direct |
| Fichthorn John | Director | 40,896 | 748,397 $ | Oct 1, 2026 | direct |
| Tracy John R. | Director | 39,000 | 713,700 $ | Oct 1, 2026 | direct |
| Blevins Tony J | Director | 25,000 | 457,500 $ | Oct 1, 2026 | direct |
| Craythorne Anthony | Chief Revenue Officer | 13,522 | 247,453 $ | Aug 3, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Oct 1, 2026 | White Yue Zhou | Director | Other | 12,000 | 0.00 | – |
| Oct 1, 2026 | Blevins Tony J | Director | Other | 12,000 | 0.00 | – |
| Oct 1, 2026 | Tracy John R. | Director | Other | 12,000 | 0.00 | – |
| Oct 1, 2026 | Fichthorn John | Director | Other | 12,000 | 0.00 | – |
| Oct 1, 2026 | Clancy James C | Chief Operating Officer | Other | 150,000 | 0.00 | – |
| Oct 1, 2026 | Patel Hiral | Chief Accounting Officer | Other | 50,000 | 0.00 | – |
| Oct 1, 2026 | Jaworksi Don | Director | Other | 12,000 | 0.00 | – |
| Aug 3, 2026 | Craythorne Anthony | Chief Revenue Officer | Sell | 1,478 | 10.73 | 15,856 |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: October 30, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.