American Tower Corporation
MX ˙ BMV ˙ US03027X1000
SecurityMX:AMT / American Tower Corporation
InstitutionJanus Henderson Group Plc
Latest Disclosed Ownership61,462 shares
Latest Disclosed Value $ 10,589,417
Janus Henderson Group Plc reports 70.03% decrease in ownership of AMT / American Tower Corporation

On May 18, 2026 - Janus Henderson Group Plc filed a 13F-HR/A form disclosing ownership of 61,462 shares of American Tower Corporation (MX:AMT) valued at $10,589,417 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 205,080 shares of American Tower Corporation. This represents a change in shares of -70.03% 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)
2026-05-18 2026-03-31 13F/A-1 AMERICAN TOWER COM 03027X100 61,462 -143,618 -70.03 10,589 -70.54 0.0018
2026-05-15 2026-03-31 13F AMERICAN TOWER COM 03027X100 61,462 -143,618 10,589 0.0020
2026-02-17 2025-12-31 13F AMERICAN TOWER CORP COM 03027X100 205,080 -51,667 -20.12 35,945 -27.20 0.0161
2025-11-14 2025-09-30 13F AMERICAN TOWER CORP COM 03027X100 256,747 -1,812,400 -87.59 49,374 -89.20 0.0225
2025-08-14 2025-06-30 13F AMERICAN TOWER CORP COM 03027X100 2,069,147 31,128 1.53 457,313 4.09 0.2242
2025-05-15 2025-03-31 13F AMERICAN TOWER CORP COM 03027X100 2,038,019 21,764 1.08 439,359 18.81 0.2408
2025-02-14 2024-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,016,255 -208,242 -9.36 369,788 -28.52 0.1880
2024-11-14 2024-09-30 13F AMERICAN TOWER CORP COM 03027X100 2,224,497 125,438 5.98 517,316 26.79 0.2648
2024-08-14 2024-06-30 13F AMERICAN TOWER CORP COM 03027X100 2,099,059 4,402 0.21 408,021 -1.41 0.2185
2024-05-15 2024-03-31 13F AMERICAN TOWER CORP COM 03027X100 2,094,657 -19,375 -0.92 413,876 -9.32 0.2258
2024-02-14 2023-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,114,032 -7,566 -0.36 456,395 30.81 0.2722
2023-11-14 2023-09-30 13F AMERICAN TOWER CORP COM 03027X100 2,121,598 -473,587 -18.25 348,905 -30.68 0.2285
2023-08-14 2023-06-30 13F AMERICAN TOWER CORP COM 03027X100 2,595,185 -416,820 -13.84 503,303 -18.22 0.3130
2023-05-15 2023-03-31 13F AMERICAN TOWER CORP COM 03027X100 3,012,005 -653,572 -17.83 615,447 -20.75 0.4058
2023-02-14 2022-12-31 13F AMERICAN TOWER CORP COM 03027X100 3,665,577 -608,919 -14.25 776,595 -15.39 0.5548
2023-01-13 2022-09-30 13F/A-1 AMERICAN TOWER CORP COM 03027X100 4,274,496 158,357 3.85 917,817 -12.77 0.6877
2022-11-14 2022-09-30 13F AMERICAN TOWER CORP COM 03027X100 4,274,496 158,357 917,817 0.6871
2022-08-15 2022-06-30 13F AMERICAN TOWER CORP COM 03027X100 4,116,139 38,292 0.94 1,052,204 2.70 0.7255
2022-05-16 2022-03-31 13F AMERICAN TOWER CORP COM 03027X100 4,077,847 796,419 24.27 1,024,538 6.75 0.4947
2022-02-14 2021-12-31 13F AMERICAN TOWER CORP COM 03027X100 3,281,428 295,520 9.90 959,793 21.12 0.4003
2021-11-16 2021-09-30 13F AMERICAN TOWER CORP COM 03027X100 2,985,908 5,215 0.17 792,446 -1.60 0.3466
2021-08-16 2021-06-30 13F AMERICAN TOWER CORP COM 03027X100 2,980,693 217,645 7.88 805,295 21.90 0.3447
2021-05-17 2021-03-31 13F AMERICAN TOWER CORP COM 03027X100 2,763,048 -732,618 -20.96 660,619 -15.80 0.3016
2021-02-16 2020-12-31 13F AMERICAN TOWER CORP COM 03027X100 3,495,666 -413,589 -10.58 784,556 -16.97 0.3645
2020-11-16 2020-09-30 13F AMERICAN TOWER CORP COM 03027X100 3,909,255 -106,561 -2.65 944,933 -8.98 0.4926
2020-08-14 2020-06-30 13F AMERICAN TOWER CORP COM 03027X100 4,015,816 -62,768 -1.54 1,038,180 16.91 0.5828
2020-05-14 2020-03-31 13F AMERICAN TOWER CORP COM 03027X100 4,078,584 -454,912 -10.03 887,983 -14.77 0.6111
2020-02-18 2019-12-31 13F AMERICAN TOWER CORP COM 03027X100 4,533,496 435,781 10.63 1,041,818 14.98 0.5334
2019-11-14 2019-09-30 13F AMERICAN TOWER CORP COM 03027X100 4,097,715 -56,165 -1.35 906,106 6.70 0.4908
2019-07-31 2019-06-30 13F AMERICAN TOWER CORP COM 03027X100 4,153,880 -311,590 -6.98 849,214 -3.49 0.4624
2019-04-30 2019-03-31 13F AMERICAN TOWER CORP COM 03027X100 4,465,470 296,836 7.12 879,958 33.44 0.4877
2019-02-06 2018-12-31 13F AMERICAN TOWER CORP COM 03027X100 4,168,634 -3,403,371 -44.95 659,451 -40.06 0.4206
2018-11-09 2018-09-30 13F AMERICAN TOWER CORP COM 03027X100 7,572,005 -171,581 -2.22 1,100,215 -1.45 0.5879
2018-08-10 2018-06-30 13F AMERICAN TOWER CORP COM 03027X100 7,743,586 -271,245 -3.38 1,116,396 -4.14 0.6364
2018-05-14 2018-03-31 13F AMERICAN TOWER CORP COM 03027X100 8,014,831 -769,220 -8.76 1,164,603 -7.07 0.6863
2018-03-12 2017-12-31 13F/A-1 AMERICAN TOWER CORP COM 03027X100 8,784,051 915,518 11.64 1,253,237 16.53 0.7717
2018-02-09 2017-12-31 13F AMERICAN TOWER CORP COM 03027X100 8,784,051 915,518 1,253,237
2017-11-14 2017-09-30 13F AMERICAN TOWER CORP COM 03027X100 7,868,533 400,117 5.36 1,075,458 8.83 0.6893
2017-08-17 2017-06-30 13F/A-1 AMERICAN TOWER CORP COM 03027X100 7,468,416 7,092,413 1,886.27 988,214 2,062.25 0.6735
2017-08-14 2017-06-30 13F AMERICAN TOWER CORP COM 03027X100 7,468,416 7,092,413 988,214
2017-05-03 2017-03-31 13F AMERICAN TOWER CORP COM 03027X100 376,003 41,878 12.53 45,703 29.42 0.3209
2017-01-30 2016-12-31 13F AMERICAN TOWER CORP COM 03027X100 334,125 -22,215 -6.23 35,315 -12.56 0.2605
2016-10-24 2016-09-30 13F AMERICAN TOWER CORP COM 03027X100 356,340 1,482 0.42 40,386 0.18 0.2976
2016-07-29 2016-06-30 13F AMERICAN TOWER CORP COM 03027X100 354,858 5,211 1.49 40,312 12.58 0.3352
2016-05-12 2016-03-31 13F AMERICAN TOWER CORP COM 03027X100 349,647 46,210 15.23 35,806 21.69 0.2904
2016-02-03 2015-12-31 13F AMERICAN TOWER CORP COM 03027X100 303,437 -2,804 -0.92 29,423 9.25 0.2361
2015-11-16 2015-09-30 13F AMERICAN TOWER CORP COM 03027X100 306,241 8,020 2.69 26,932 -3.21 0.2372
2015-08-17 2015-06-30 13F AMERICAN TOWER CORP COM 03027X100 298,221 -98,573 -24.84 27,824 -25.58 0.2186
2015-06-02 2015-03-31 13F/A-1 AMERICAN TOWER CORP COM 03027X100 396,794 25,477 6.86 37,386 1.83 0.2884
2015-05-15 2015-03-31 13F AMERICAN TOWER CORP COM 03027X100 396,794 37,386
2015-02-12 2014-12-31 13F AMERICAN TOWER CORP COM 03027X100 371,317 79,511 27.25 36,714 34.37 0.2647
2014-11-12 2014-09-30 13F AMERICAN TOWER CORP COM 03027X100 291,806 -7,529 -2.52 27,323 1.47 0.2570
2014-08-13 2014-06-30 13F AMERICAN TOWER CORP COM 03027X100 299,335 -19,862 -6.22 26,927 3.03 0.2514
2014-05-08 2014-03-31 13F AMERICAN TOWER CORP COM 03027X100 319,197 66,304 26.22 26,134 29.50 0.2544
2014-01-14 2013-12-31 13F AMERICAN TOWER CORP COM 03027X100 252,893 -204,500 -44.71 20,180 -40.51 0.2039
2013-11-12 2013-09-30 13F AMERICAN TOWER CORP COM 03027X100 457,393 -28,196 -5.81 33,923 -2.99 0.3742
2013-08-15 2013-06-30 13F AMERICAN TOWER CORP COM 03027X100 485,589 485,589 34,970 0.4088
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.