Quantum Corporation (QMCO) Ownership
QMCO ownership summary
as of October 18, 2026- Institutions
- 35.6% of shares outstanding
- Insiders
- 37.92% of shares outstanding
- Shares outstanding
- 39.4M
- Float
- 34.1M shares available to trade
- Short interest
- 59.55% 3.1M shares short
- Days to cover
- 1.96 short interest up 52.7% vs prior month
- Institutions 35.60%
- Insiders 37.92%
- Other investors 26.47%
QMCO top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Alyeska Investment Group, L.P. | 6.73% | 2.7M | $49.0M | +2.7M (0.0%) | June 30, 2026 |
| 2 | Oaktree Capital Management LLC | 5.10% | 2.0M | $37.2M | +2.0M (0.0%) | June 30, 2026 |
| 3 | Neuberger Berman Group LLC | 2.95% | 1.2M | $21.5M | +1.2M (0.0%) | June 30, 2026 |
| 4 | Ashford Capital Management Inc | 2.64% | 1.0M | $19.2M | +1.0M (0.0%) | June 30, 2026 |
| 5 | Portolan Capital Management, LLC | 2.59% | 1.0M | $18.9M | +1.0M (0.0%) | June 30, 2026 |
| 6 | Marshall Wace Asset Management Ltd | 1.81% | 713K | $13.2M | +675,547 (+1,800.1%) | June 30, 2026 |
| 7 | Vanguard Capital Management, LLC | 1.54% | 606K | $11.2M | +66,266 (+12.3%) | June 30, 2026 |
| 8 | Manatuck Hill Partners LLC | 0.89% | 350K | $6.5M | +350,000 (0.0%) | June 30, 2026 |
| 9 | BlackRock Inc | 0.69% | 273K | $5.0M | +55,498 (+25.5%) | June 30, 2026 |
| 10 | Cinctive Capital Management LP | 0.46% | 183K | $3.4M | +182,769 (0.0%) | June 30, 2026 |
| 11 | Bank of America Corp | 0.43% | 170K | $3.1M | +149,645 (+730.5%) | June 30, 2026 |
| 12 | Geode Capital Management, LLC | 0.42% | 165K | $3.0M | +5,421 (+3.4%) | June 30, 2026 |
| 13 | Renaissance Technologies Corp | 0.39% | 155K | $2.9M | +154,516 (0.0%) | June 30, 2026 |
| 14 | SONA ASSET MANAGEMENT (US) LLC | 0.38% | 150K | $2.8M | +79,908 (+114.0%) | June 30, 2026 |
| 15 | Walleye Trading Advisors, LLC | 0.30% | 120K | $2.2M | +120,044 (0.0%) | June 30, 2026 |
| 16 | Centiva Capital LP | 0.25% | 100K | $1.8M | +100,000 (0.0%) | June 30, 2026 |
| 17 | KKM Financial LLC | 0.23% | 90K | $1.7M | +90,274 (0.0%) | June 30, 2026 |
| 18 | Vanguard Fiduciary Trust Co | 0.23% | 89K | $1.6M | +8,862 (+11.0%) | June 30, 2026 |
| 19 | Qube Research & Technologies | 0.21% | 81K | $1.5M | +80,977 (0.0%) | June 30, 2026 |
| 20 | State Street Corp | 0.19% | 76K | $1.4M | +3,100 (+4.3%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 20 holders added 10.0M shares and 0 cut 0.
QMCO top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Neuberger Intrinsic Value I | 1.12% | 442K | $8.2M | −334,474 (−43.1%) | September 30, 2026 |
| 2 | Vanguard MStar Total Stk Mkt Idx Invest | 1.07% | 421K | $7.8M | — | August 31, 2026 |
| 3 | Schwab US Small-Cap ETF™ | 0.34% | 135K | $2.5M | +90 (+0.1%) | September 30, 2026 |
| 4 | iShares Micro-Cap ETF | 0.25% | 98K | $1.8M | −675 (−0.7%) | September 30, 2026 |
| 5 | Mango Growth ETF | 0.23% | 91K | $1.7M | — | September 30, 2026 |
| 6 | Fidelity Extended Market Index | 0.18% | 73K | $1.3M | −4,654 (−6.0%) | August 31, 2026 |
| 7 | Fidelity Nasdaq Composite Index | 0.15% | 60K | $1.1M | +51,430 (+637.1%) | August 31, 2026 |
| 8 | iShares Core S&P Total US Stock Mkt ETF | 0.10% | 40K | $741,787 | +30 (+0.1%) | September 30, 2026 |
| 9 | Morgan Stanley Pathway Sm-Md Cp Eq ETF | 0.10% | 40K | $735,486 | — | September 30, 2026 |
| 10 | Neuberger US Sm Cp Intrs Val USD I Acc | 0.09% | 37K | $689,748 | +37,324 (0.0%) | June 30, 2026 |
| 11 | Methodical FR Global Dynamic B5 | 0.09% | 37K | $683,723 | −10,564 (−22.2%) | December 31, 2025 |
| 12 | Methodical FR Equity B1 | 0.07% | 29K | $529,360 | −9,328 (−24.6%) | December 31, 2025 |
| 13 | Fidelity Total Market Index | 0.07% | 28K | $508,385 | — | August 31, 2026 |
| 14 | Abante Quant Value FI | 0.07% | 27K | $502,009 | −17,139 (−38.7%) | August 31, 2026 |
| 15 | Fidelity Series Total Market Index | 0.06% | 24K | $446,606 | — | August 31, 2026 |
| 16 | Column Small Cap Select | 0.05% | 20K | $377,824 | — | September 30, 2026 |
| 17 | Golden Eagle Dynamic Hypergrowth ETF | 0.05% | 20K | $361,192 | −3,162 (−13.9%) | September 30, 2026 |
| 18 | Schwab US Broad Market ETF™ | 0.04% | 17K | $307,101 | — | September 30, 2026 |
| 19 | NEI Multi-Strategy Global Equity Pool I | 0.04% | 15K | $268,311 | +14,519 (0.0%) | September 30, 2026 |
| 20 | Fidelity Nasdaq Composite ETF | 0.04% | 14K | $267,480 | — | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
QMCO insider transactions
latest 3| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2025-10-02 | Laura A Nash | Sell | $10.86 | 611 | $6,635 |
| 2025-10-01 | Laura A Nash | Sell | $9.91 | 118 | $1,169 |
| 2025-09-12 | Laura A Nash | Sell | $7.40 | 284 | $2,102 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
QMCO shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns QMCO
Institutional investors own 35.6% of Quantum's shares and insiders 37.92%. The largest holder is Alyeska Investment Group, L.P. with 6.73% of the shares (2.7M), as of June 30, 2026. Among the top 20 institutions, 20 added shares and 0 reduced their stake in the latest filings. Short interest is 59.55% of the float, or 1.96 days of average trading volume. The share count rose 623.2% since 2014.
Related: QMCO analyst forecast, QMCO key metrics. See the QMCO stock overview for the latest quote and news.
QMCO ownership FAQ
Who owns the most Quantum stock?
The largest shareholders of Quantum are Alyeska Investment Group, L.P. (6.73%), Oaktree Capital Management LLC (5.10%), Neuberger Berman Group LLC (2.95%), Ashford Capital Management Inc (2.64%), Portolan Capital Management, LLC (2.59%).
What percentage of Quantum is owned by institutions?
Institutions hold 35.6% of Quantum's shares outstanding; insiders hold 37.92%.
Which funds own Quantum?
The largest fund holders of Quantum are Neuberger Intrinsic Value I (1.12%), Vanguard MStar Total Stk Mkt Idx Invest (1.07%), Schwab US Small-Cap ETF™ (0.34%), iShares Micro-Cap ETF (0.25%), Mango Growth ETF (0.23%).
What is Quantum's short interest?
3.1M shares of Quantum were sold short, 59.55% of the float; at the average daily volume it would take 1.96 days to cover.
Are insiders buying or selling Quantum?
Of the latest 3 reported insider transactions in Quantum (since September 12, 2025), 0 were purchases and 3 were sales.
How many shares of Quantum are outstanding?
Quantum has 39.4M shares outstanding, of which 34.1M are in the public float.