American Tower Corporation
MX ˙ BMV ˙ US03027X1000
SecurityMX:AMT / American Tower Corporation
InstitutionMarshall Wace, Llp
Latest Disclosed Ownership751,254 shares
Latest Disclosed Value $ 129,651,413
Marshall Wace, Llp ownership in AMT / American Tower Corporation

On May 14, 2026 - Marshall Wace, Llp filed a 13F-HR form disclosing ownership of 751,254 shares of American Tower Corporation (MX:AMT) valued at $129,651,413 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 311,411 shares of American Tower Corporation. This represents a change in shares of 141.24% during the quarter.

Marshall Wace, Llp has a history of taking positions in derivatives of the underlying security (AMT) in the form of stock options. The firm currently holds call options representing 200 of underlying shares valued at $34,516 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

MX:AMT / American Tower Corporation Historical Put/Call Ratio
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 C REIT 03027X100 751,254 439,843 141.24 129,651 137.13 0.1291
2026-02-13 2025-12-31 13F AMERICAN TOWER C REIT 03027X100 311,411 311,411 54,674 0.0498
2025-11-13 2025-09-30 13F AMERICAN TOWER C REIT 03027X100 0 -509,621 -100.00 0 -100.00
2025-08-13 2025-06-30 13F AMERICAN TOWER C REIT 03027X100 509,621 -182,780 -26.40 112,636 -25.24 0.1269
2025-05-15 2025-03-31 13F AMERICAN TOWER C REIT 03027X100 692,401 692,401 150,666 0.1913
2025-02-13 2024-12-31 13F AMERICAN TOWER C REIT 03027X100 0 -47,564 -100.00 0 -100.00
2024-11-14 2024-09-30 13F AMERICAN TOWER C REIT 03027X100 47,564 -414,172 -89.70 11,061 -87.68 0.0135
2024-08-14 2024-06-30 13F AMERICAN TOWER C REIT 03027X100 461,736 461,736 89,752 0.1198
2024-02-14 2023-12-31 13F AMERICAN TOWER C REIT 03027X100 0 -1,647 -100.00 0 -100.00
2023-11-14 2023-09-30 13F AMERICAN TOWER C REIT 03027X100 1,647 -6,760 -80.41 271 -83.44 0.0005
2023-08-14 2023-06-30 13F AMERICAN TOWER C REIT 03027X100 8,407 8,407 1,630 0.0032
2023-02-14 2022-12-31 13F AMERICAN TOWER C REIT 03027X100 0 -70,518 -100.00 0 -100.00
2022-11-14 2022-09-30 13F AMERICAN TOWER C REIT 03027X100 70,518 70,518 15,140 0.0332
2021-05-17 2021-03-31 13F AMERICAN TOWER C REIT 03027X100 0 -55,699 -100.00 0 -100.00
2021-02-16 2020-12-31 13F AMERICAN TOWER C REIT 03027X100 55,699 8,086 16.98 12,503 8.63 0.0678
2020-11-16 2020-09-30 13F AMERICAN TOWER C REIT 03027X100 47,613 47,613 -14.52 11,510 -7.94 0.0737
2020-08-13 2020-06-30 13F AMERICAN TOWER C REIT 03027X100 0 -1,130 -100.00 0 -100.00
2020-05-15 2020-03-31 13F AMERICAN TOWER C REIT 03027X100 1,130 1,130 246 0.0025
2019-11-14 2019-09-30 13F AMERICAN TOWER C REIT 03027X100 0 -29,494 -100.00 0 -100.00
2019-08-14 2019-06-30 13F AMERICAN TOWER C REIT 03027X100 29,494 29,494 6,031 0.0496
2017-08-04 2017-06-30 13F AMERICAN TOWER C REIT 03027X100 0 -4,958 -100.00 0 -100.00
2017-05-12 2017-03-31 13F AMERICAN TOWER C REIT 03027X100 4,958 4,958 605 0.0292
2016-11-10 2016-09-30 13F AMERICAN TOWER C REIT 03027X100 0 -18,783 -100.00 0 -100.00
2016-08-12 2016-06-30 13F AMERICAN TOWER C REIT 03027X100 18,783 13,438 251.41 2,134 290.13 0.0179
2016-05-13 2016-03-31 13F AMERICAN TOWER C REIT 03027X100 5,345 -53,355 -90.89 547 -90.39 0.0053
2016-02-10 2015-12-31 13F AMERICAN TOWER C REIT 03027X100 58,700 56,019 2,089.48 5,691 2,311.44 0.0534
2015-11-12 2015-09-30 13F AMERICAN TOWER C REIT 03027X100 2,681 -64,343 -96.00 236 -96.23 0.0029
2015-08-14 2015-06-30 13F AMERICAN TOWER C REIT 03027X100 67,024 -337,338 -83.42 6,252 -83.58 0.0816
2015-05-11 2015-03-31 13F AMERICAN TOWER C REIT 03027X100 404,362 175,680 76.82 38,070 68.41 0.4960
2015-02-17 2014-12-31 13F AMERICAN TOWER C REIT 03027X100 228,682 46,013 25.19 22,605 32.17 0.2984
2014-11-13 2014-09-30 13F AMERICAN TOWER C REIT 03027X100 182,669 -107,250 -36.99 17,103 -34.44 0.2468
2014-08-14 2014-06-30 13F AMERICAN TOWER C REIT 03027X100 289,919 135,299 87.50 26,087 106.07 0.3840
2014-05-14 2014-03-31 13F AMERICAN TOWER C REIT 03027X100 154,620 154,620 12,659 0.2302
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-14 2026-03-31 13F AMERICAN TOWER C EQUITY OPTION Call 200 0.00 35 -2.86 n/a n/a n/a
2026-02-13 2025-12-31 13F AMERICAN TOWER C EQUITY OPTION Call 200 35 n/a n/a n/a
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.