아메리칸 타워 코퍼레이션
MX ˙ BMV ˙ US03027X1000
SecurityMX:AMT / American Tower Corporation
InstitutionBaird Financial Group, Inc.
Latest Disclosed Ownership142,714 shares
Latest Disclosed Value $ 24,629,582
Baird Financial Group, Inc. reports 17.61% increase in ownership of AMT / American Tower Corporation

On May 14, 2026 - Baird Financial Group, Inc. filed a 13F-HR form disclosing ownership of 142,714 shares of American Tower Corporation (MX:AMT) valued at $24,629,582 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 121,350 shares of American Tower Corporation. This represents a change in shares of 17.61% during the quarter.

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)
2026-05-14 2026-03-31 13F AMERICAN TOWER COM 03027X100 142,714 21,364 17.61 24,630 15.60 0.0207
2026-02-13 2025-12-31 13F AMERICAN TOWER CORP NEW COM COMMON 03027X100 121,350 -943 -0.77 21,305 -9.41 0.0332
2025-11-13 2025-09-30 13F AMERICAN TOWER CORP NEW COM COMMON 03027X100 122,293 -2,579 -2.07 23,519 -14.79 0.0378
2025-08-13 2025-06-30 13F AMERICAN TOWER CORP NEW COM COMMON 03027X100 124,872 4,002 3.31 27,600 4.94 0.0484
2025-05-15 2025-03-31 13F AMERICAN TOWER CORP NEW COM COMMON 03027X100 120,870 210 0.17 26,301 18.85 0.0506
2025-02-14 2024-12-31 13F AMERICAN TOWER REIT COMMON 03027X100 120,660 -19,791 -14.09 22,130 -32.25 0.0423
2024-11-14 2024-09-30 13F AMERICAN TOWER REIT COMMON 03027X100 140,451 13,958 11.03 32,663 32.85 0.0634
2024-08-14 2024-06-30 13F AMERICAN TOWER REIT COMMON 03027X100 126,493 -29,156 -18.73 24,588 -20.05 0.0510
2024-05-14 2024-03-31 13F AMERICAN TOWER REIT COMMON 03027X100 155,649 1,398 0.91 30,755 -7.64 0.0645
2024-02-14 2023-12-31 13F AMERICAN TOWER REIT COMMON 03027X100 154,251 13,754 9.79 33,300 44.13 0.0759
2023-11-13 2023-09-30 13F AMERICAN TOWER REIT COMMON 03027X100 140,497 -51,013 -26.64 23,105 -37.79 0.0630
2023-08-11 2023-06-30 13F AMERICAN TOWER REIT COMMON 03027X100 191,510 -22,469 -10.50 37,141 -15.06 0.0980
2023-05-15 2023-03-31 13F AMERICAN TOWER REIT COMMON 03027X100 213,979 8,345 4.06 43,725 101,583.72 0.1079
2023-02-13 2022-12-31 13F AMERICAN TOWER REIT COMMON 03027X100 205,634 22,051 12.01 44 -99.89 0.1147
2022-11-15 2022-09-30 13F AMERICAN TOWER REIT COMMON 03027X100 183,583 20,542 12.60 39,415 -5.42 0.1161
2022-08-08 2022-06-30 13F AMERICAN TOWER REIT COMMON 03027X100 163,041 19,131 13.29 41,672 15.27 0.1157
2022-05-13 2022-03-31 13F AMERICAN TOWER REIT COMMON 03027X100 143,910 -103 -0.07 36,153 -14.17 0.0893
2022-02-09 2021-12-31 13F AMERICAN TOWER COMMON 03027X100 144,013 4,288 3.07 42,123 13.59 0.0985
2021-11-12 2021-09-30 13F AMERICAN TOWER COMMON 03027X100 139,725 -34,734 -19.91 37,085 -21.31 0.0948
2021-08-11 2021-06-30 13F AMERICAN TOWER COMMON 03027X100 174,459 38,236 28.07 47,128 44.72 0.1225
2021-05-13 2021-03-31 13F AMERICAN TOWER COMMON 03027X100 136,223 -100,360 -42.42 32,566 -38.67 0.0913
2021-02-11 2020-12-31 13F AMERICAN TOWER COMMON 03027X100 236,583 -16,730 -6.60 53,103 -13.28 0.1587
2020-11-12 2020-09-30 13F AMERICAN TOWER COMMON 03027X100 253,313 -23,994 -8.65 61,233 -14.59 0.2098
2020-10-22 2020-06-30 13F/A-1 AMERICAN TOWER COMMON 03027X100 277,307 89,453 47.62 71,695 75.27 0.2701
2020-08-14 2020-06-30 13F AMERICAN TOWER COMMON 03027X100 245,676 57,822 57,403 113,759.7042
2020-05-14 2020-03-31 13F AMERICAN TOWER COMMON 03027X100 187,854 -39,384 -17.33 40,905 -21.67 0.1868
2020-02-14 2019-12-31 13F AMERICAN TOWER COMMON 03027X100 227,238 8,553 3.91 52,224 7.99 0.1875
2019-11-14 2019-09-30 13F AMERICAN TOWER Common 03027X100 218,685 1,990 0.92 48,358 9.15 0.1905
2019-08-14 2019-06-30 13F AMERICAN TOWER COMMON 03027X100 216,695 8,425 4.05 44,303 7.95 0.1723
2019-05-14 2019-03-31 13F AMERICAN TOWER REIT COMMON 03027X100 208,270 6,596 3.27 41,042 28.65 0.2400
2019-02-14 2018-12-31 13F AMERICAN TOWER REIT COMMON 03027X100 201,674 11,977 6.31 31,903 16.77 0.2165
2018-11-13 2018-09-30 13F AMERICAN TOWER REIT COMMON 03027X100 189,697 9,309 5.16 27,322 5.06 0.1712
2018-08-13 2018-06-30 13F AMERICAN TOWER REIT COMMON 03027X100 180,388 -16,202 -8.24 26,007 -8.98 0.1765
2018-05-14 2018-03-31 13F AMERICAN TOWER REIT COMMON 03027X100 196,590 4,367 2.27 28,572 4.18 0.2012
2018-02-09 2017-12-31 13F AMERICAN TOWER REIT COMMON 03027X100 192,223 5,037 2.69 27,425 7.19 0.1943
2017-11-14 2017-09-30 13F AMERICAN TOWER REIT COMMON 03027X100 187,186 -11,462 -5.77 25,585 -2.66 0.1930
2017-08-14 2017-06-30 13F AMERICAN TOWER REIT COMMON 03027X100 198,648 -616 -0.31 26,285 8.53 0.2059
2017-06-19 2017-03-31 13F/A-1 AMERICAN TOWER REIT COMMON 03027X100 199,264 37,863 23.46 24,219 41.99 0.1959
2017-05-09 2017-03-31 13F AMERICAN TOWER REIT COMMON 03027X100 199,264 24,219
2017-02-10 2016-12-31 13F AMERICAN TOWER REIT COMMON 03027X100 161,401 -2,294 -1.40 17,057 -8.06 0.1481
2016-11-10 2016-09-30 13F AMERICAN TOWER REIT COMMON 03027X100 163,695 4,336 2.72 18,552 2.32 0.1662
2016-08-11 2016-06-30 13F AMERICAN TOWER REIT COMMON 03027X100 159,359 -7,399 -4.44 18,132 6.22 0.1663
2016-05-12 2016-03-31 13F AMERICAN TOWER REIT COMMON 03027X100 166,758 19,775 13.45 17,071 19.80 0.1633
2016-02-11 2015-12-31 13F AMERICAN TOWER REIT COMMON 03027X100 146,983 11,742 8.68 14,250 19.76 0.1425
2015-11-12 2015-09-30 13F AMERICAN TOWER REIT COMMON 03027X100 135,241 -1,968 -1.43 11,899 -7.04 0.1265
2015-08-14 2015-06-30 13F AMERICAN TOWER REIT COMMON 03027X100 137,209 137,209 12,800 0.1260
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.