| SC 13G/A | 2012-04-11 | BlackRock Inc. | QUANTUM CORP /DE/ | 11,355,491 | 4.8% | EDGAR |
| SC 13G/A | 2012-02-14 | FMR LLC | QUANTUM CORP /DE/ | 19,702,752 | 8.4% | EDGAR |
| SC 13G/A | 2012-02-14 | PRIVATE CAPITAL MANAGEMENT | QUANTUM CORP /DE/ | 83 | 8.3% | EDGAR |
| SC 13G | 2012-02-14 | WELLINGTON MANAGEMENT CO LLP | QUANTUM CORP /DE/ | 15,569,123 | 6.7% | EDGAR |
| SC 13G | 2012-02-09 | BlackRock Inc. | QUANTUM CORP /DE/ | 11,807,226 | 5.0% | EDGAR |
| SC 13G/A | 2012-02-08 | Capital Research Global Investors | QUANTUM CORP /DE/ | 18,279,499 | 7.8% | EDGAR |
| SC 13G/A | 2012-02-06 | Porter Orlin LLC | QUANTUM CORP /DE/ | 2,849,000 | 1.2% | EDGAR |
| SC 13G/A | 2012-01-06 | SOROS FUND MANAGEMENT LLC | QUANTUM CORP /DE/ | 21,208,239 | 8.3% | EDGAR |
| SC 13G/A | 2011-12-09 | BlackRock Inc. | QUANTUM CORP /DE/ | 11,640,797 | 5.0% | EDGAR |
| SC 13G | 2011-08-15 | SOROS FUND MANAGEMENT LLC | QUANTUM CORP /DE/ | 14,788,593 | 6.0% | EDGAR |
| SC 13G/A | 2011-08-10 | FMR LLC | QUANTUM CORP /DE/ | 23,190,600 | 10.1% | EDGAR |
| SC 13G | 2011-06-30 | Porter Orlin LLC | QUANTUM CORP /DE/ | 2,037,700 | 0.9% | EDGAR |
| SC 13G/A | 2011-02-14 | PRIVATE CAPITAL MANAGEMENT | QUANTUM CORP /DE/ | 82 | 8.2% | EDGAR |
| SC 13G/A | 2011-02-14 | NORDEA NORTH AMERICAN VALUE FUND | QUANTUM CORP /DE/ | 8,538,386 | 3.9% | EDGAR |
| SC 13G | 2011-02-14 | FMR LLC | QUANTUM CORP /DE/ | 13,220,961 | 6.0% | EDGAR |
| SC 13G/A | 2011-02-11 | RENAISSANCE TECHNOLOGIES LLC | QUANTUM CORP /DE/ | 5,161,600 | 2.3% | EDGAR |
| SC 13G/A | 2011-02-10 | Capital Research Global Investors | QUANTUM CORP /DE/ | 24,492,710 | 11.0% | EDGAR |
| SC 13G | 2011-02-08 | BlackRock Inc. | QUANTUM CORP /DE/ | 11,653,183 | 5.3% | EDGAR |
| SC 13G/A | 2010-11-12 | WELLS FARGO & CO/MN | QUANTUM CORP /DE/ | 8,939,130 | 4.1% | EDGAR |
| SC 13G/A | 2010-10-08 | BlackRock Inc. | QUANTUM CORP /DE/ | 10,800,253 | 5.0% | EDGAR |