American Tower Corporation

The full register, from 13F filings

The Register tab above is hand research: a dozen holders, each traced to the filing it came from. This asks the same question of the whole market for the quarter ended 31-mar-2026, where 1,725 managers reported a position. Broad where the research is deep, and shallow in the ways a 13F always is.

Built from 13F filings, which report US listed, long, US custodied positions only. A register from this source is a floor rather than a level: a holder's true position can be far larger, as BlackRock's ASML stake shows at 1.28m shares in a 13F against 26.3m in its 13G/A. Holdings held through derivatives, outside US custody, or below a manager's reporting obligation do not appear. Where a holder is marked as a family, its total sums several separate filing entities and describes something no single filing describes; the constituent entities and their share counts are listed so the total can be checked. That roll-up can legitimately exceed the family's own Schedule 13G, because a 13G is filed by one legal entity: Vanguard reports Alphabet through ten advisory entities, and The Vanguard Group Inc itself reported zero after its January 2026 disaggregation.

What a reader needs to know to read these numbers

• Holdings scope. American Tower's Q2 2026 10-Q and FY2025 10-K were both searched for 'equity method', 'unconsolidated', 'joint venture', 'noncontrolling interest', 'CoreSite', 'Stonepeak', 'Vertical Bridge', 'ATC Europe', 'ATC Telecom Infrastructure', 'Brookfield', 'India', 'Data Center' and 'investment in'. Only one genuine minority equity-method holding was found and is recorded above: the Stonepeak Development Partnership (Denver, CO data center JV, formed 2024). It is unsized beyond the $14.6 million initial 2024 asset contribution; no ownership percentage or current carrying value is disclosed in either filing.
• Excluded as consolidated, not a holding. (1) The US Data Center business (the former CoreSite Realty, acquired 2021): the Q2 2026 10-Q states Stonepeak Partners LP holds approximately 29% of the outstanding common equity and 100% of the outstanding mandatorily convertible preferred equity in this business, meaning Stonepeak is a MINORITY investor IN American Tower's subsidiary (the reverse direction), while American Tower retains and reports control and consolidates the business. No holding is recorded for CoreSite/the US Data Center business. (2) ATC Europe: the Q2 2026 10-Q states ATC Europe holds an 87% and an 83% controlling interest in certain European country subsidiaries; these are consolidated operating subsidiaries of American Tower (via ATC Europe), not equity-method investees, and are excluded as wholly/majority owned operating subsidiaries per the brief.
• ATC TIPL (India) fully divested, no current holding. American Tower sold 100% of ATC Telecom Infrastructure Private Limited (its India tower business) to Data Infrastructure Trust, an infrastructure investment trust sponsored by an affiliate of Brookfield Asset Management, in a transaction that closed 12 September 2024 for total consideration of approximately 182 billion INR (about $2.2 billion), recording a $1.2 billion loss on sale. The consideration structure referenced 'VIL OCDs' and 'VIL Shares' (Vodafone Idea Limited instruments held via ATC TIPL) that were distributed/transferred as part of closing and deducted from the total consideration American Tower received; American Tower retained no residual equity interest in ATC TIPL, DIT, or the VIL instruments after closing. This is a completed 2024 divestiture, not a current AMT holding, and is not recorded.
• Combined, unattributable balance excluded per rule 5. The Q2 2026 10-Q fair-value table shows 'Investments in equity securities' of $18.8 million (Level 1) plus $194.5 million (Level 2), $213.3 million combined, recorded within Notes receivable and other non-current assets. No individual issuer or count of positions is disclosed for this balance in either the Q2 2026 10-Q or the FY2025 10-K (which showed $15.3 million Level 1 plus $161.6 million Level 2 at 31 Dec 2025). Because the split across investees is undisclosed, no individual holding is recorded for it, per the rule against assigning a combined balance to one investee.
• Cohen & Steers value correction. See the Cohen & Steers register row method_note: its Q2 2026 13F information table reports VALUE in thousands of dollars rather than whole dollars (the pre-2023 SEC convention), inconsistent with every other filer in this register; value_usd for that row is corrected by a factor of 1,000, verified against implied per-share price consistency with the other ten filers (all cluster at $163 to $164 per share for the same 30 June 2026 date).
• Register reconciliation on Vanguard and BlackRock. American Tower's 2026 proxy statement (record date 23 March 2026, citing the most recent Schedule 13G/A filings) reports The Vanguard Group at 61,022,228 shares (13.08%, per a 13G/A filed 13 Feb 2024, now dated given the January 2026 Vanguard reporting realignment referenced in the same proxy) and BlackRock, Inc. at 43,047,962 shares (9.23%, per a 13G/A filed 5 Feb 2025). The register instead uses each manager's Q2 2026 Form 13F-HR (30 June 2026 position date): Vanguard's successor entities sum to 58,289,583 shares and BlackRock reports 45,796,561 shares. The BlackRock 13F figure is higher than its February 2025 13G figure, consistent with a position increase over that period; the Vanguard 13F figure is lower than the stale 2024 13G figure, plausibly reflecting portfolio changes plus the disaggregation of Vanguard's 13F reporting structure since January 2026, under which subsidiaries that formerly rolled into the parent's beneficial ownership now report separately.
• American Tower has a single class of common stock and no founder or dual-class control structure. The 2026 proxy states insider ownership, individually and as a 19-person group, is well under 1% of outstanding shares; the former CEO, Olivier Puech, retired effective 2 January 2026.
• Percentages in the register (other than the insider row's proxy-marked asterisk) are computed by this research against 465,960,048 common shares outstanding as of 21 July 2026 (Q2 2026 10-Q cover page).
• Market capitalization of $80.76 billion and the $173.31 share price are stockanalysis.com's figures as of 17 August 2026 (intraday). Cross-check: 465,960,048 shares x $173.31 implies approximately $80.75 billion, consistent with the reported market cap.
• Self-gate check: summing the eleven non-insider register rows (Vanguard through Capital Research Global Investors) gives 195,461,554 shares against 465,960,048 shares outstanding, or 41.9%, within the expected 25 to 45 percent range.