Alliant Energy Corporation
US ˙ NasdaqGS ˙ US0188021085

SecurityLNT / Alliant Energy Corporation
InstitutionJanus Henderson Group Plc
Latest Disclosed Ownership11,273,621 shares
Latest Disclosed Value $ 808,995,539
Janus Henderson Group Plc reports 1.25% increase in ownership of LNT / Alliant Energy Corporation

On May 18, 2026 - Janus Henderson Group Plc filed a 13F-HR/A form disclosing ownership of 11,273,621 shares of Alliant Energy Corporation (US:LNT) valued at $808,995,043 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 11,134,938 shares of Alliant Energy Corporation. This represents a change in shares of 1.25% during the quarter. The current value of the position is $798,059,631 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-18 2026-03-31 13F/A-1 ALLIANT ENERGY COM 018802108 11,273,621 138,683 1.25 808,996 11.76 0.1364
2026-05-15 2026-03-31 13F ALLIANT ENERGY COM 018802108 11,273,621 138,683 808,996 0.1501
2026-02-17 2025-12-31 13F ALLIANT ENERGY COM 018802108 11,134,938 223,793 2.05 723,882 -1.58 0.3242
2025-11-14 2025-09-30 13F ALLIANT ENERGY COM 018802108 10,911,145 135,623 1.26 735,520 12.88 0.3358
2025-08-14 2025-06-30 13F ALLIANT ENERGY COM 018802108 10,775,522 -92,440 -0.85 651,596 -5.70 0.3194
2025-05-15 2025-03-31 13F ALLIANT ENERGY COM 018802108 10,867,962 99,803 0.93 690,985 8.50 0.3788
2025-02-14 2024-12-31 13F ALLIANT ENERGY COM 018802108 10,768,159 76,987 0.72 636,829 -1.85 0.3237
2024-11-14 2024-09-30 13F ALLIANT ENERGY COM 018802108 10,691,172 65,110 0.61 648,847 19.96 0.3321
2024-08-14 2024-06-30 13F ALLIANT ENERGY COM 018802108 10,626,062 46,587 0.44 540,867 1.44 0.2896
2024-05-15 2024-03-31 13F ALLIANT ENERGY COM 018802108 10,579,475 984,963 10.27 533,205 8.33 0.2909
2024-02-14 2023-12-31 13F ALLIANT ENERGY COM 018802108 9,594,512 1,520,528 18.83 492,198 25.82 0.2936
2023-11-14 2023-09-30 13F ALLIANT ENERGY COM 018802108 8,073,984 2,234,554 38.27 391,184 27.65 0.2562
2023-08-14 2023-06-30 13F ALLIANT ENERGY COM 018802108 5,839,430 2,169,103 59.10 306,453 56.36 0.1906
2023-05-15 2023-03-31 13F ALLIANT ENERGY COM 018802108 3,670,327 25,371 0.70 195,995 -2.61 0.1292
2023-02-14 2022-12-31 13F ALLIANT ENERGY COM 018802108 3,644,956 1,108 0.03 201,238 4.22 0.1438
2023-01-13 2022-09-30 13F/A-1 ALLIANT ENERGY COM 018802108 3,643,848 -1,311,635 -26.47 193,088 -33.52 0.1447
2022-11-14 2022-09-30 13F ALLIANT ENERGY COM 018802108 3,643,848 -1,311,635 193,088 0.1446
2022-08-15 2022-06-30 13F ALLIANT ENERGY COM 018802108 4,955,483 -3,045,709 -38.07 290,441 -41.90 0.2003
2022-05-16 2022-03-31 13F ALLIANT ENERGY COM 018802108 8,001,192 -78,326 -0.97 499,914 0.66 0.2414
2022-02-14 2021-12-31 13F ALLIANT ENERGY COM 018802108 8,079,518 -88,107 -1.08 496,648 8.62 0.2072
2021-11-16 2021-09-30 13F ALLIANT ENERGY COM 018802108 8,167,625 -316,010 -3.72 457,223 -3.35 0.2000
2021-08-16 2021-06-30 13F ALLIANT ENERGY COM 018802108 8,483,635 -121,764 -1.41 473,047 1.50 0.2025
2021-05-17 2021-03-31 13F ALLIANT ENERGY COM 018802108 8,605,399 131,656 1.55 466,069 6.74 0.2128
2021-02-16 2020-12-31 13F ALLIANT ENERGY COM 018802108 8,473,743 2,581,492 43.81 436,651 43.48 0.2029
2020-11-16 2020-09-30 13F ALLIANT ENERGY COM 018802108 5,892,251 420,061 7.68 304,336 16.25 0.1587
2020-08-14 2020-06-30 13F ALLIANT ENERGY COM 018802108 5,472,190 1,886,433 52.61 261,789 51.19 0.1469
2020-05-14 2020-03-31 13F ALLIANT ENERGY COM 018802108 3,585,757 1,445,053 67.50 173,157 47.82 0.1192
2020-02-18 2019-12-31 13F ALLIANT ENERGY COM 018802108 2,140,704 -436,946 -16.95 117,139 -15.73 0.0600
2019-11-14 2019-09-30 13F ALLIANT ENERGY COM 018802108 2,577,650 -207,857 -7.46 139,012 1.68 0.0753
2019-07-31 2019-06-30 13F ALLIANT ENERGY COM 018802108 2,785,507 -375,153 -11.87 136,713 -8.22 0.0744
2019-04-30 2019-03-31 13F ALLIANT ENERGY COM 018802108 3,160,660 138,177 4.57 148,962 16.65 0.0826
2019-02-06 2018-12-31 13F ALLIANT ENERGY COM 018802108 3,022,483 362,749 13.64 127,700 12.79 0.0814
2018-11-09 2018-09-30 13F ALLIANT ENERGY COM 018802108 2,659,734 -42,936 -1.59 113,224 -1.01 0.0605
2018-08-10 2018-06-30 13F ALLIANT ENERGY COM 018802108 2,702,670 -942,642 -25.86 114,377 -23.21 0.0652
2018-05-14 2018-03-31 13F ALLIANT ENERGY COM 018802108 3,645,312 -43,407 -1.18 148,947 -5.24 0.0878
2018-03-12 2017-12-31 13F/A-1 ALLIANT ENERGY COM 018802108 3,688,719 -138,462 -3.62 157,177 -1.21 0.0968
2018-02-09 2017-12-31 13F ALLIANT ENERGY COM 018802108 3,688,719 -138,462 157,177
2017-11-14 2017-09-30 13F ALLIANT ENERGY COM 018802108 3,827,181 189,180 5.20 159,096 8.87 0.1020
2017-08-17 2017-06-30 13F/A-1 ALLIANT ENERGY COM 018802108 3,638,001 3,606,695 11,520.78 146,138 11,685.32 0.0996
2017-08-14 2017-06-30 13F ALLIANT ENERGY COM 018802108 3,638,001 3,606,695 146,138
2017-05-03 2017-03-31 13F ALLIANT ENERGY COM 018802108 31,306 0 0.00 1,240 4.55 0.0087
2017-01-30 2016-12-31 13F ALLIANT ENERGY COM 018802108 31,306 3,200 11.39 1,186 10.12 0.0087
2016-10-24 2016-09-30 13F ALLIANT ENERGY COM 018802108 28,106 0 0.00 1,077 -3.84 0.0079
2016-07-29 2016-06-30 13F ALLIANT ENERGY COM 018802108 28,106 14,053 100.00 1,120 7.28 0.0093
2016-05-12 2016-03-31 13F ALLIANT ENERGY COM 018802108 14,053 0 0.00 1,044 18.91 0.0085
2016-02-03 2015-12-31 13F ALLIANT ENERGY COM 018802108 14,053 0 0.00 878 6.81 0.0070
2015-11-16 2015-09-30 13F ALLIANT ENERGY COM 018802108 14,053 0 0.00 822 1.36 0.0072
2015-08-17 2015-06-30 13F ALLIANT ENERGY COM 018802108 14,053 0 0.00 811 -8.36 0.0064
2015-06-02 2015-03-31 13F/A-1 ALLIANT ENERGY COM 018802108 14,053 0 0.00 885 -5.14 0.0068
2015-05-15 2015-03-31 13F ALLIANT ENERGY COM 018802108 14,053 885
2015-02-12 2014-12-31 13F ALLIANT ENERGY COM 018802108 14,053 0 0.00 933 19.77 0.0067
2014-11-12 2014-09-30 13F ALLIANT ENERGY COM 018802108 14,053 0 0.00 779 -8.89 0.0073
2014-08-13 2014-06-30 13F ALLIANT ENERGY COM 018802108 14,053 0 0.00 855 7.14 0.0080
2014-05-08 2014-03-31 13F ALLIANT ENERGY COM 018802108 14,053 2,000 16.59 798 28.30 0.0078
2014-01-14 2013-12-31 13F ALLIANT ENERGY COM 018802108 12,053 0 0.00 622 4.19 0.0063
2013-11-12 2013-09-30 13F ALLIANT ENERGY COM 018802108 12,053 0 0.00 597 -0.17 0.0066
2013-08-15 2013-06-30 13F ALLIANT ENERGY COM 018802108 12,053 12,053 598 0.0070
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.