| Type | Filed | Filer | Subject | Shares Owned | Percent Owned | |
|---|---|---|---|---|---|---|
| SC 13G | 2018-02-13 | STATE STREET CORP | ALLIANT ENERGY CORP | - | 5.1% | EDGAR |
| SC 13G/A | 2018-02-12 | VANGUARD GROUP INC | ALLIANT ENERGY CORP | 24,537,881 | 10.6% | EDGAR |
| SC 13G/A | 2018-02-08 | BlackRock Inc. | ALLIANT ENERGY CORP | 18,971,645 | 8.2% | EDGAR |
| SC 13G/A | 2017-03-10 | VANGUARD GROUP INC | ALLIANT ENERGY CORP | 22,890,250 | 10.0% | EDGAR |
| SC 13G/A | 2017-02-09 | VANGUARD GROUP INC | ALLIANT ENERGY CORP | 22,323,761 | 9.8% | EDGAR |
| SC 13G | 2017-02-09 | STATE STREET CORP | ALLIANT ENERGY CORP | - | 5.3% | EDGAR |
| SC 13G/A | 2017-01-19 | BlackRock Inc. | ALLIANT ENERGY CORP | 20,757,445 | 9.1% | EDGAR |
| SC 13G/A | 2016-02-10 | VANGUARD GROUP INC | ALLIANT ENERGY CORP | 8,155,455 | 7.2% | EDGAR |
| SC 13G/A | 2016-01-08 | BlackRock Inc. | ALLIANT ENERGY CORP | 11,906,180 | 10.5% | EDGAR |
| SC 13G/A | 2015-02-11 | VANGUARD GROUP INC | ALLIANT ENERGY CORP | 7,055,313 | 6.4% | EDGAR |
| SC 13G/A | 2015-01-09 | BlackRock Inc. | ALLIANT ENERGY CORP | 11,552,624 | 10.4% | EDGAR |
| SC 13G | 2014-02-10 | VANGUARD GROUP INC | ALLIANT ENERGY CORP | 6,252,764 | 5.6% | EDGAR |
| SC 13G/A | 2014-02-07 | BlackRock Inc. | ALLIANT ENERGY CORP | 11,285,235 | 10.2% | EDGAR |
| SC 13G/A | 2014-01-31 | BlackRock Inc. | ALLIANT ENERGY CORP | 11,070,398 | 10.0% | EDGAR |
| SC 13G/A | 2013-02-01 | BlackRock Inc. | ALLIANT ENERGY CORP | 9,740,268 | 8.8% | EDGAR |
| SC 13G/A | 2012-02-09 | BlackRock Inc. | ALLIANT ENERGY CORP | 10,243,616 | 9.2% | EDGAR |
| SC 13G/A | 2011-02-02 | BlackRock Inc. | ALLIANT ENERGY CORP | 9,253,326 | 8.4% | EDGAR |
| SC 13G | 2010-01-29 | BlackRock Inc. | ALLIANT ENERGY CORP | 8,476,492 | 7.7% | EDGAR |
| SC 13G | 2009-02-05 | BARCLAYS GLOBAL INVESTORS NA /CA/ | ALLIANT ENERGY CORP | 3,818,400 | 3.5% | EDGAR |
| SC 13G | 2008-02-05 | BARCLAYS GLOBAL INVESTORS NA /CA/ | ALLIANT ENERGY CORP | 8,689,800 | 7.9% | EDGAR |