| Type | Filed | Filer | Subject | Shares Owned | Percent Owned | |
|---|---|---|---|---|---|---|
| SC 13G/A | 2015-02-11 | PRICE T ROWE ASSOCIATES INC /MD/ | NORTHWESTERN CORP | 2,318,335 | 5.0% | EDGAR |
| SC 13G/A | 2015-02-10 | VANGUARD GROUP INC | NORTHWESTERN CORP | 3,221,132 | 6.9% | EDGAR |
| SC 13G/A | 2015-01-15 | BlackRock Inc. | NORTHWESTERN CORP | 4,585,078 | 10.0% | EDGAR |
| SC 13G/A | 2014-12-10 | JPMORGAN CHASE & CO | NORTHWESTERN CORP | - | - | EDGAR |
| SC 13G | 2014-12-09 | DEUTSCHE BANK AG\ | NORTHWESTERN CORP | 5,083,825 | 11.0% | EDGAR |
| SC 13G/A | 2014-02-12 | VANGUARD GROUP INC | NORTHWESTERN CORP | 2,478,781 | 6.4% | EDGAR |
| SC 13G | 2014-02-12 | MUNDER CAPITAL MANAGEMENT | NORTHWESTERN CORP | 385,996 | 1.0% | EDGAR |
| SC 13G/A | 2014-02-10 | PRICE T ROWE ASSOCIATES INC /MD/ | NORTHWESTERN CORP | 2,283,215 | 5.9% | EDGAR |
| SC 13G/A | 2014-01-17 | JPMORGAN CHASE & CO | NORTHWESTERN CORP | - | - | EDGAR |
| SC 13G/A | 2014-01-10 | BlackRock Inc. | NORTHWESTERN CORP | 4,425,064 | 11.5% | EDGAR |
| SC 13G | 2013-02-13 | MUNDER CAPITAL MANAGEMENT | NORTHWESTERN CORP | 2,122,156 | 5.7% | EDGAR |
| SC 13G/A | 2013-02-11 | PRICE T ROWE ASSOCIATES INC /MD/ | NORTHWESTERN CORP | 2,299,005 | 6.1% | EDGAR |
| SC 13G/A | 2013-02-11 | VANGUARD GROUP INC | NORTHWESTERN CORP | 2,276,887 | 6.1% | EDGAR |
| SC 13G | 2013-01-29 | JPMORGAN CHASE & CO | NORTHWESTERN CORP | 2,227,705 | 5.9% | EDGAR |
| SC 13G/A | 2013-01-11 | BlackRock Inc. | NORTHWESTERN CORP | 3,853,868 | 10.4% | EDGAR |
| SC 13G/A | 2012-11-09 | BlackRock Inc. | NORTHWESTERN CORP | 3,732,430 | 10.0% | EDGAR |
| SC 13G/A | 2012-02-13 | MUNDER CAPITAL MANAGEMENT | NORTHWESTERN CORP | 4,674,328 | 4.6% | EDGAR |
| SC 13G/A | 2012-02-13 | MUNDER CAPITAL MANAGEMENT | NORTHWESTERN CORP | 4,674,328 | 4.6% | EDGAR |
| SC 13G/A | 2012-02-09 | BlackRock Inc. | NORTHWESTERN CORP | 3,337,127 | 9.2% | EDGAR |
| SC 13G/A | 2012-02-08 | PRICE T ROWE ASSOCIATES INC /MD/ | NORTHWESTERN CORP | 2,308,085 | 6.3% | EDGAR |