American Tower Corporation
US ˙ NYSE ˙ US03027X1000

SecurityAMT / American Tower Corporation
InstitutionSigma Planning Corp
Latest Disclosed Ownership2,279 shares
Latest Disclosed Value $ 393,303
Sigma Planning Corp reports 6.71% decrease in ownership of AMT / American Tower Corporation

On May 4, 2026 - Sigma Planning Corp filed a 13F-HR form disclosing ownership of 2,279 shares of American Tower Corporation (US:AMT) valued at $393,310 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 30, 2026 disclosing 2,443 shares of American Tower Corporation. This represents a change in shares of -6.71% during the quarter. The current value of the position is $415,325 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)
2026-05-04 2026-03-31 13F AMERICAN TOWER COM 03027X100 2,279 -164 -6.71 393 -2.48 0.0109
2026-01-30 2025-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,443 -242 -9.01 403 -21.90 0.0111
2025-11-10 2025-09-30 13F AMERICAN TOWER CORP COM 03027X100 2,685 -339 -11.21 516 -22.75 0.0147
2025-08-05 2025-06-30 13F AMERICAN TOWER CORP COM 03027X100 3,024 -1,682 -35.74 668 -34.77 0.0201
2025-05-02 2025-03-31 13F AMERICAN TOWER CORP COM 03027X100 4,706 -2,657 -36.09 1,024 -24.15 0.0327
2025-02-03 2024-12-31 13F AMERICAN TOWER CORP COM 03027X100 7,363 514 7.50 1,350 -15.20 0.0424
2024-11-04 2024-09-30 13F AMERICAN TOWER CORP COM 03027X100 6,849 542 8.59 1,593 29.85 0.0488
2024-08-06 2024-06-30 13F AMERICAN TOWER CORP COM 03027X100 6,307 -300 -4.54 1,226 -6.05 0.0388
2024-05-02 2024-03-31 13F AMERICAN TOWER CORP COM 03027X100 6,607 3,226 95.42 1,306 79.01 0.0410
2024-02-01 2023-12-31 13F AMERICAN TOWER CORP COM 03027X100 3,381 -4,274 -55.83 730 -42.05 0.0571
2023-11-06 2023-09-30 13F AMERICAN TOWER CORP COM 03027X100 7,655 -2,494 -24.57 1,259 -36.08 0.0472
2023-08-02 2023-06-30 13F AMERICAN TOWER CORP COM 03027X100 10,149 -300 -2.87 1,968 -7.82 0.0707
2023-05-08 2023-03-31 13F AMERICAN TOWER CORP COM 03027X100 10,449 1,221 13.23 2,135 9.21 0.0710
2023-01-24 2022-12-31 13F AMERICAN TOWER CORP COM 03027X100 9,228 222 2.47 1,955 1.09 0.0699
2022-11-10 2022-09-30 13F AMERICAN TOWER CORP COM 03027X100 9,006 353 4.08 1,934 -12.57 0.0737
2022-08-11 2022-06-30 13F AMERICAN TOWER CORP COM 03027X100 8,653 -990 -10.27 2,212 -8.71 0.0769
2022-04-20 2022-03-31 13F AMERICAN TOWER CORP COM 03027X100 9,643 1,335 16.07 2,423 -0.29 0.0726
2022-02-02 2021-12-31 13F AMERICAN TOWER REIT 03027X100 8,308 -663 -7.39 2,430 2.06 0.0677
2021-10-28 2021-09-30 13F AMERICAN TOWER CORP COM 03027X100 8,971 -200 -2.18 2,381 -3.91 0.0716
2021-08-13 2021-06-30 13F AMERICAN TOWER REIT 03027X100 9,171 500 5.77 2,478 19.54 0.0739
2021-05-06 2021-03-31 13F AMERICAN TOWER REIT 03027X100 8,671 -2,086 -19.39 2,073 -14.16 0.0662
2021-02-09 2020-12-31 13F AMERICAN TOWER CORP COM 03027X100 10,757 326 3.13 2,415 -4.24 0.0821
2020-11-03 2020-09-30 13F AMERICAN TOWER CORP COM 03027X100 10,431 4 0.04 2,522 -6.45 0.0998
2020-07-31 2020-06-30 13F AMERICAN TOWER CORP COM 03027X100 10,427 2,176 26.37 2,696 50.03 0.1183
2020-05-01 2020-03-31 13F AMERICAN TOWER CORP COM 03027X100 8,251 -11 -0.13 1,797 -5.37 0.1067
2020-02-03 2019-12-31 13F AMERICAN TOWER CORP COM 03027X100 8,262 115 1.41 1,899 5.38 0.0801
2019-11-01 2019-09-30 13F AMERICAN TOWER CORP COM 03027X100 8,147 3,286 67.60 1,802 81.29 0.0865
2019-08-01 2019-06-30 13F AMERICAN TOWER CORP COM 03027X100 4,861 191 4.09 994 8.04 0.0512
2019-05-01 2019-03-31 13F AMERICAN TOWER CORP COM 03027X100 4,670 1,825 64.15 920 104.44 0.0522
2019-01-31 2018-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,845 258 9.97 450 19.68 0.0327
2018-11-07 2018-09-30 13F AMERICAN TOWER CORP COM 03027X100 2,587 -137 -5.03 376 -4.33 0.0221
2018-08-02 2018-06-30 13F AMERICAN TOWER CORP COM 03027X100 2,724 -43 -1.55 393 -2.24 0.0263
2018-05-11 2018-03-31 13F AMERICAN TOWER CORP COM 03027X100 2,767 219 8.59 402 10.44 0.0294
2018-02-07 2017-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,548 345 15.66 364 20.93 0.0280
2017-11-06 2017-09-30 13F AMERICAN TOWER CORP COM 03027X100 2,203 24 1.10 301 4.51 0.0248
2017-08-02 2017-06-30 13F AMERICAN TOWER CORP COM 03027X100 2,179 102 4.91 288 14.29 0.0271
2017-04-24 2017-03-31 13F AMERICAN TOWER CORP COM 03027X100 2,077 -372 -15.19 252 -2.70 0.0244
2017-01-23 2016-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,449 -22 -0.89 259 -7.50 0.0283
2016-11-07 2016-09-30 13F AMERICAN TOWER CORP COM 03027X100 2,471 88 3.69 280 3.32 0.0332
2016-07-22 2016-06-30 13F AMERICAN TOWER CORP COM 03027X100 2,383 29 1.23 271 12.45 0.0353
2016-04-18 2016-03-31 13F AMERICAN TOWER CORP COM 03027X100 2,354 -567 -19.41 241 -14.84 0.0329
2016-01-20 2015-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,921 2,921 24.09 283 17.43 0.0396
2015-11-02 2015-09-30 13F AMERICAN TOWER CORP COM 03027X100 0 -3,197 -100.00 0 -100.00
2015-07-14 2015-06-30 13F AMERICAN TOWER CORP COM 03027X100 3,197 330 11.51 298 10.37 0.0411
2015-04-23 2015-03-31 13F AMERICAN TOWER CORP COM 03027X100 2,867 -77 -2.62 270 -7.22 0.0358
2015-02-13 2014-12-31 13F AMERICAN TOWER CORP COM 03027X100 2,944 2,944 291 0.0385
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.