| Type | Filed | Filer | Subject | Shares Owned | Percent Owned | |
|---|---|---|---|---|---|---|
| SC 13G/A | 2014-02-14 | Flynn James E | NxStage Medical, Inc. | 5,570,639 | 9.1% | EDGAR |
| SC 13G | 2014-02-12 | VANGUARD GROUP INC | NxStage Medical, Inc. | 3,349,994 | 5.5% | EDGAR |
| SC 13G/A | 2014-02-07 | FEINBERG LARRY N | NxStage Medical, Inc. | 3,523,543 | 5.8% | EDGAR |
| SC 13G/A | 2014-02-06 | BLAIR WILLIAM & CO/IL | NxStage Medical, Inc. | 3,894,244 | 6.4% | EDGAR |
| SC 13G/A | 2014-02-04 | MUBADALA DEVELOPMENT CO PJSC | NxStage Medical, Inc. | 3,009,597 | 4.9% | EDGAR |
| SC 13G | 2014-01-30 | BlackRock Inc. | NxStage Medical, Inc. | 3,766,504 | 6.2% | EDGAR |
| SC 13G | 2014-01-03 | MUBADALA DEVELOPMENT CO PJSC | NxStage Medical, Inc. | 3,143,114 | 5.2% | EDGAR |
| SC 13G | 2013-12-30 | FEINBERG LARRY N | NxStage Medical, Inc. | 3,410,067 | 5.6% | EDGAR |
| SC 13G/A | 2013-12-10 | WELLS FARGO & COMPANY/MN | NxStage Medical, Inc. | 3,001,780 | 5.0% | EDGAR |
| SC 13D/A | 2013-11-12 | ORBIMED ADVISORS LLC | NxStage Medical, Inc. | 2,879,216 | 4.7% | EDGAR |
| SC 13D/A | 2013-07-02 | ORBIMED ADVISORS LLC | NxStage Medical, Inc. | 3,136,100 | 5.2% | EDGAR |
| SC 13G/A | 2013-03-29 | WELLS FARGO & COMPANY/MN | NxStage Medical, Inc. | 4,953,932 | 8.4% | EDGAR |
| SC 13D/A | 2013-03-19 | Utterberg David S | NxStage Medical, Inc. | 2,910,839 | 4.9% | EDGAR |
| SC 13D/A | 2013-03-04 | Utterberg David S | NxStage Medical, Inc. | 3,228,937 | 5.4% | EDGAR |
| SC 13G/A | 2013-02-14 | NEXT CENTURY GROWTH INVESTORS LLC | NxStage Medical, Inc. | 0 | 0.0% | EDGAR |
| SC 13G/A | 2013-02-13 | WELLS FARGO & COMPANY/MN | NxStage Medical, Inc. | 4,926,511 | 8.4% | EDGAR |
| SC 13G/A | 2013-02-05 | BLAIR WILLIAM & CO/IL | NxStage Medical, Inc. | 3,860,316 | 6.5% | EDGAR |
| SC 13D/A | 2013-01-11 | Utterberg David S | NxStage Medical, Inc. | 3,890,069 | 6.6% | EDGAR |
| SC 13G/A | 2012-12-14 | Flynn James E | NxStage Medical, Inc. | 5,917,079 | 10.0% | EDGAR |
| SC 13D/A | 2012-11-19 | Utterberg David S | NxStage Medical, Inc. | 4,510,685 | 7.6% | EDGAR |