American Tower Corporation
US ˙ NYSE ˙ US03027X1000

SecurityAMT / American Tower Corporation
InstitutionFirst Manhattan Co
Latest Disclosed Ownership195,448 shares
Latest Disclosed Value $ 33,730,416
First Manhattan Co reports 2.60% decrease in ownership of AMT / American Tower Corporation

On May 15, 2026 - First Manhattan Co filed a 13F-HR form disclosing ownership of 195,448 shares of American Tower Corporation (US:AMT) valued at $33,730,416 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 200,674 shares of American Tower Corporation. This represents a change in shares of -2.60% during the quarter. The current value of the position is $35,618,444 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)
2026-05-15 2026-03-31 13F AMERICAN TOWER COM 03027X100 195,448 -5,226 -2.60 33,730 -5.18 0.0935
2026-02-17 2025-12-31 13F AMERICAN TOWER CORP COM 03027X100 200,674 -8,148 -3.90 35,573 -12.20 0.0934
2025-11-14 2025-09-30 13F AMERICAN TOWER CORP COM 03027X100 208,822 -12,046 -5.45 40,516 -17.64 0.1070
2025-08-14 2025-06-30 13F AMERICAN TOWER CORP COM 03027X100 220,868 1,354 0.62 49,190 2.98 0.1389
2025-05-15 2025-03-31 13F AMERICAN TOWER CORP COM 03027X100 219,514 9,246 4.40 47,766 14.07 0.1393
2025-02-14 2024-12-31 13F AMERICAN TOWER CORP COM 03027X100 210,268 17,524 9.09 41,875 -6.58 0.1228
2024-11-14 2024-09-30 13F AMERICAN TOWER CORP COM 03027X100 192,744 1,443 0.75 44,825 19.62 0.1329
2024-08-15 2024-06-30 13F/A-1 AMERICAN TOWER CORP COM 03027X100 191,301 77,523 68.14 37,473 66.68 0.1202
2024-08-14 2024-06-30 13F AMERICAN TOWER CORP COM 03027X100 191,301 77,523 37,473 0.1202
2024-05-15 2024-03-31 13F AMERICAN TOWER CORP COM 03027X100 113,778 -372,930 -76.62 22,481 -78.26 0.0728
2024-02-13 2023-12-31 13F AMERICAN TOWER CORP COM 03027X100 486,708 -68,298 -12.31 103,414 13.30 0.3588
2023-11-14 2023-09-30 13F AMERICAN TOWER CORP COM 03027X100 555,006 -153,569 -21.67 91,271 -33.58 0.3370
2023-08-14 2023-06-30 13F AMERICAN TOWER CORP COM 03027X100 708,575 -103,416 -12.74 137,421 -17.18 0.5034
2023-05-15 2023-03-31 13F AMERICAN TOWER CORP COM 03027X100 811,991 15,928 2.00 165,922 -1.62 0.6363
2023-02-14 2022-12-31 13F AMERICAN TOWER CORP COM 03027X100 796,063 43,934 5.84 168,654 4.44 0.6180
2022-11-14 2022-09-30 13F AMERICAN TOWER CORP COM 03027X100 752,129 81,069 12.08 161,482 -5.85 0.6838
2022-08-15 2022-06-30 13F AMERICAN TOWER CORP COM 03027X100 671,060 41,547 6.60 171,516 8.45 0.6913
2022-05-16 2022-03-31 13F AMERICAN TOWER CORP COM 03027X100 629,513 10,583 1.71 158,146 -12.64 0.5173
2022-02-14 2021-12-31 13F AMERICAN TOWER CORP COM 03027X100 618,930 27,984 4.74 181,037 15.43 0.5966
2021-11-15 2021-09-30 13F AMERICAN TOWER CORP COM 03027X100 590,946 6,295 1.08 156,842 -0.69 0.5778
2021-08-16 2021-06-30 13F AMERICAN TOWER CORP COM 03027X100 584,651 6,201 1.07 157,937 14.21 0.5765
2021-05-14 2021-03-31 13F AMERICAN TOWER CORP COM 03027X100 578,450 239,206 70.51 138,284 81.60 0.5961
2021-02-16 2020-12-31 13F AMERICAN TOWER CORP COM 03027X100 339,244 338,048 28,264.88 76,146 26,248.10 0.3644
2020-11-12 2020-09-30 13F AMERICAN TOWER COMMON 03027X100 1,196 11 0.93 289 -5.56 0.0015
2020-08-14 2020-06-30 13F AMERICAN TOWER COMMON 03027X100 1,185 -102 -7.93 306 9.29 0.0018
2020-05-06 2020-03-31 13F AMERICAN TOWER COMMON 03027X100 1,287 11 0.86 280 -4.44 0.0018
2020-02-13 2019-12-31 13F AMERICAN TOWER COMMON 03027X100 1,276 9 0.71 293 4.64 0.0015
2019-11-13 2019-09-30 13F AMERICAN TOWER COMMON 03027X100 1,267 38 3.09 280 11.55 0.0015
2019-08-16 2019-06-30 13F AMERICAN TOWER COMMON 03027X100 1,229 60 5.13 251 9.13 0.0014
2019-04-12 2019-03-31 13F AMERICAN TOWER COMMON 03027X100 1,169 550 88.85 230 137.11 0.0013
2019-01-30 2018-12-31 13F AMERICAN TOWER COMMON 03027X100 619 18 3.00 97 11.49 0.0006
2018-10-15 2018-09-30 13F AMERICAN TOWER COMMON 03027X100 601 0 0.00 87 1.16 0.0005
2018-08-01 2018-06-30 13F AMERICAN TOWER COMMON 03027X100 601 -139 -18.78 86 -19.63 0.0005
2018-04-20 2018-03-31 13F AMERICAN TOWER COMMON 03027X100 740 224 43.41 107 46.58 0.0006
2018-01-22 2017-12-31 13F AMERICAN TOWER COMMON 03027X100 516 -49 -8.67 73 -5.19 0.0004
2017-10-25 2017-09-30 13F AMERICAN TOWER COMMON 03027X100 565 138 32.32 77 37.50 0.0004
2017-08-10 2017-06-30 13F/A-2 AMERICAN TOWER COMMON 03027X100 427 49 12.96 56 24.44 0.0003
2017-08-01 2017-06-30 13F/A-1 AMERICAN TOWER COMMON 03027X100 427 0 56 0.0003
2017-07-28 2017-06-30 13F AMERICAN TOWER COMMON 03027X100 427 49 56
2017-04-25 2017-03-31 13F/A-1 AMERICAN TOWER COMMON 03027X100 378 0 0.00 45 15.38 0.0003
2017-04-24 2017-03-31 13F AMERICAN TOWER COMMON SHARES 03027X100 396 44
2017-01-25 2016-12-31 13F AMERICAN TOWER COMMON 03027X100 378 -18 -4.55 39 -11.36 0.0002
2016-10-20 2016-09-30 13F AMERICAN TOWER COMMON SHARES 03027X100 396 0 0.00 44 0.00 0.0003
2016-07-14 2016-06-30 13F AMERICAN TOWER COMMON SHARES 03027X100 396 0 0.00 44 10.00 0.0003
2016-04-22 2016-03-31 13F AMERICAN TOWER COMMON SHARES 03027X100 396 -400 -50.25 40 -48.05 0.0002
2016-01-20 2015-12-31 13F AMERICAN TOWER COMMON SHARES 03027X100 796 501 169.83 77 208.00 0.0005
2015-10-26 2015-09-30 13F AMERICAN TOWER COMMON SHARES 03027X100 295 199 207.29 25 212.50 0.0002
2015-07-17 2015-06-30 13F AMERICAN TOWER COMMON SHARES 03027X100 96 78 433.33 8 700.00 0.0000
2015-04-30 2015-03-31 13F AMERICAN TOWER COMMON SHARES 03027X100 18 -400 -95.69 1 -97.56 0.0000
2015-01-20 2014-12-31 13F AMERICAN TOWER COMMON SHARES 03027X100 418 400 2,222.22 41 4,000.00 0.0002
2014-10-23 2014-09-30 13F AMERICAN TOWER COMMON SHARES 03027X100 18 0 0.00 1 0.00 0.0000
2014-08-14 2014-06-30 13F/A-1 AMERICAN TOWER COMMON SHARES 03027X100 18 0 0.00 1 0.00 0.0000
2014-05-16 2014-03-31 13F AMERICAN TOWER COMMON SHARES 03027X100 18 0 0.00 1 0.00 0.0000
2014-02-04 2013-12-31 13F AMERICAN TOWER COMMON SHARES 03027X100 18 18 1 0.0000
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.