American Tower Corporation
US ˙ NYSE ˙ US03027X1000

SecurityAMT / American Tower Corporation
InstitutionMairs & Power Inc
Latest Disclosed Ownership2,020 shares
Latest Disclosed Value $ 348,612
Mairs & Power Inc ownership in AMT / American Tower Corporation

On May 13, 2026 - Mairs & Power Inc filed a 13F-HR form disclosing ownership of 2,020 shares of American Tower Corporation (US:AMT) valued at $348,612 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 2,020 shares of American Tower Corporation. This represents a change in shares of 0.00% during the quarter. The current value of the position is $391,698 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)
2026-05-13 2026-03-31 13F AMERICAN TOWER COM 03027X100 2,020 0 0.00 349 -1.69 0.0036
2026-02-17 2025-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,020 -1,011 -33.36 355 -39.18 0.0034
2025-11-14 2025-09-30 13F AMERICAN TOWER CORP COM 03027X100 3,031 971 47.14 583 27.91 0.0055
2025-08-14 2025-06-30 13F AMERICAN TOWER CORP COM 03027X100 2,060 40 1.98 455 3.64 0.0045
2025-05-15 2025-03-31 13F AMERICAN TOWER CORP COM 03027X100 2,020 0 0.00 440 18.65 0.0046
2025-02-14 2024-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,020 0 0.00 370 -21.11 0.0036
2024-11-14 2024-09-30 13F AMERICAN TOWER CORP COM 03027X100 2,020 0 0.00 470 19.64 0.0044
2024-08-14 2024-06-30 13F AMERICAN TOWER CORP COM 03027X100 2,020 0 0.00 393 -1.75 0.0038
2024-05-15 2024-03-31 13F AMERICAN TOWER CORP COM 03027X100 2,020 -191 -8.64 399 -16.35 0.0039
2024-02-14 2023-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,211 -188 -7.84 477 21.07 0.0050
2023-11-14 2023-09-30 13F AMERICAN TOWER CORP COM 03027X100 2,399 176 7.92 395 -8.58 0.0046
2023-08-14 2023-06-30 13F AMERICAN TOWER CORP COM 03027X100 2,223 9 0.41 431 -4.65 0.0047
2023-05-15 2023-03-31 13F AMERICAN TOWER CORP COM 03027X100 2,214 0 0.00 452 -3.62 0.0052
2023-02-14 2022-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,214 0 0.00 469 -1.26 0.0056
2022-11-14 2022-09-30 13F AMERICAN TOWER CORP COM 03027X100 2,214 0 0.00 475 -16.08 0.0060
2022-08-15 2022-06-30 13F AMERICAN TOWER CORP COM 03027X100 2,214 189 9.33 566 11.20 0.0068
2022-05-16 2022-03-31 13F AMERICAN TOWER CORP COM 03027X100 2,025 5 0.25 509 -13.87 0.0051
2022-02-14 2021-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,020 0 0.00 591 10.26 0.0055
2021-11-15 2021-09-30 13F AMERICAN TOWER CORP COM 03027X100 2,020 -758 -27.29 536 -28.53 0.0054
2021-08-16 2021-06-30 13F AMERICAN TOWER CORP COM 03027X100 2,778 0 0.00 750 12.95 0.0074
2021-05-14 2021-03-31 13F AMERICAN TOWER CORP COM 03027X100 2,778 -367 -11.67 664 -5.95 0.0070
2021-02-16 2020-12-31 13F AMERICAN TOWER CORP COM 03027X100 3,145 0 0.00 706 -7.11 0.0078
2020-11-16 2020-09-30 13F AMERICAN TOWER CORP COM 03027X100 3,145 -27 -0.85 760 -7.32 0.0095
2020-08-14 2020-06-30 13F AMERICAN TOWER CORP COM 03027X100 3,172 0 0.00 820 18.67 0.0107
2020-05-15 2020-03-31 13F AMERICAN TOWER CORP COM 03027X100 3,172 0 0.00 691 -5.21 0.0101
2020-02-14 2019-12-31 13F American Tower Cl A COM 03027X100 3,172 -200 -5.93 729 -2.28 0.0083
2019-11-14 2019-09-30 13F American Tower Cl A COM 03027X100 3,372 27 0.81 746 9.06 0.0090
2019-08-14 2019-06-30 13F American Tower Cl A COM 03027X100 3,345 0 0.00 684 3.79 0.0082
2019-05-15 2019-03-31 13F American Tower Cl A COM 03027X100 3,345 0 0.00 659 24.57 0.0080
2019-02-14 2018-12-31 13F American Tower Cl A COM 03027X100 3,345 0 0.00 529 8.85 0.0071
2018-11-14 2018-09-30 13F American Tower Cl A COM 03027X100 3,345 200 6.36 486 7.28 0.0057
2018-08-14 2018-06-30 13F American Tower Cl A COM 03027X100 3,145 0 0.00 453 -0.88 0.0056
2018-05-15 2018-03-31 13F American Tower Cl A COM 03027X100 3,145 3,145 457 0.0056
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.