| SC 13G/A | 2015-02-10 | VANGUARD GROUP INC | QUANTUM CORP /DE/ | 15,435,934 | 6.0% | EDGAR |
| SC 13G/A | 2015-01-29 | BlackRock Inc. | QUANTUM CORP /DE/ | 17,134,354 | 6.7% | EDGAR |
| SC 13D/A | 2014-07-29 | Starboard Value LP | QUANTUM CORP /DE/ | 44,243,875 | 16.4% | EDGAR |
| SC 13D/A | 2014-05-13 | Starboard Value LP | QUANTUM CORP /DE/ | 44,243,875 | 16.6% | EDGAR |
| SC 13G/A | 2014-02-14 | FMR LLC | QUANTUM CORP /DE/ | 26,596,447 | 10.7% | EDGAR |
| SC 13G/A | 2014-02-14 | Amici Capital, LLC | QUANTUM CORP /DE/ | 7,329,267 | 3.0% | EDGAR |
| SC 13G | 2014-02-13 | Private Capital Management, LLC | QUANTUM CORP /DE/ | - | 4.7% | EDGAR |
| SC 13G/A | 2014-02-12 | VANGUARD GROUP INC | QUANTUM CORP /DE/ | 13,218,124 | 5.3% | EDGAR |
| SC 13G/A | 2014-01-30 | BlackRock Inc. | QUANTUM CORP /DE/ | 14,410,082 | 5.8% | EDGAR |
| SC 13D/A | 2013-05-15 | Starboard Value LP | QUANTUM CORP /DE/ | 26,128,823 | 10.3% | EDGAR |
| SC 13D/A | 2013-03-15 | Starboard Value LP | QUANTUM CORP /DE/ | 26,128,823 | 10.3% | EDGAR |
| SC 13G/A | 2013-02-15 | PRIVATE CAPITAL MANAGEMENT | QUANTUM CORP /DE/ | 83 | 8.3% | EDGAR |
| SC 13G/A | 2013-02-14 | FMR LLC | QUANTUM CORP /DE/ | 25,447,028 | 10.6% | EDGAR |
| SC 13G/A | 2013-02-14 | WELLINGTON MANAGEMENT CO LLP | QUANTUM CORP /DE/ | 1,244,746 | 0.5% | EDGAR |
| SC 13G/A | 2013-02-14 | AMICI CAPITAL, LLC | QUANTUM CORP /DE/ | 2,028,504 | 0.8% | EDGAR |
| SC 13G | 2013-02-13 | VANGUARD GROUP INC | QUANTUM CORP /DE/ | 13,636,121 | 5.7% | EDGAR |
| SC 13G | 2013-01-30 | BlackRock Inc. | QUANTUM CORP /DE/ | 12,926,180 | 5.4% | EDGAR |
| SC 13G/A | 2012-12-10 | Capital Research Global Investors | QUANTUM CORP /DE/ | - | 0.0% | EDGAR |
| SC 13D | 2012-11-01 | Starboard Value LP | QUANTUM CORP /DE/ | 26,128,823 | 10.4% | EDGAR |
| SC 13G/A | 2012-05-29 | SOROS FUND MANAGEMENT LLC | QUANTUM CORP /DE/ | 30,230,223 | 11.4% | EDGAR |