Vanguard reports 27.7M AMT shares as 5.94% stake (AMT)

Rhea-AI Filing Summary

Vanguard Portfolio Management reports beneficial ownership of 27,718,958 shares of American Tower Corp common stock, representing 5.94% of the class as of 03/31/2026. The filer discloses sole power to dispose of 27,718,958 shares and sole voting power over 122,799 shares.

The filing attributes holdings to Vanguard Portfolio Management LLC and affiliated Vanguard entities and states these holdings include securities held by Vanguard funds and managed accounts. The report is signed by the filer on 04/28/2026.

Insights

Institutional Ownership Analyst

Large passive stake reported: Vanguard holds 5.94% of AMT with full dispositive control.

Vanguard Portfolio Management discloses beneficial ownership of 5.94% of American Tower Corp, equating to 27,718,958 shares as of 03/31/2026. The filing shows sole dispositive power over all reported shares and limited sole voting power of 122,799 shares.

These holdings are reported on behalf of Vanguard-managed funds and accounts. Cash‑flow treatment and any planned transactions are not stated in the excerpt; subsequent filings would show material changes.

Key Figures

Shares beneficially owned: 27,718,958 shares Percent of class: 5.94% Sole voting power: 122,799 shares +2 more

5 metrics

Shares beneficially owned 27,718,958 shares Beneficial ownership as of 03/31/2026

Percent of class 5.94% Percent of outstanding common stock

Sole voting power 122,799 shares Number with sole power to vote

Sole dispositive power 27,718,958 shares Number with sole power to dispose

Report signature date 04/28/2026 Filing signed by Head of Global Fund Administration

Key Terms

Schedule 13G, beneficially owned, sole dispositive power, sole voting power

4 terms

Schedule 13G regulatory

"reports beneficial ownership of 27,718,958 shares (5.94%)"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

beneficially owned financial

"Amount beneficially owned: 27718958"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

sole dispositive power regulatory

"Sole power to dispose or to direct the disposition of: 27718958"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

sole voting power regulatory

"Sole power to vote or to direct the vote: 122,799"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

American Tower Corp

(Name of Issuer)

Common Stock

(Title of Class of Securities)

03027X100

(CUSIP Number)

03/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 03027X100

1

Names of Reporting Persons

Vanguard Portfolio Management

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

PENNSYLVANIA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 122,799.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 27,718,958.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

27,718,958.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.94 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: In accordance with SEC Release No. 34-39538 (January 12, 1998), this Schedule 13G reflects the securities beneficially owned, or deemed to be beneficially owned, by Vanguard Portfolio Management LLC and the following affiliates of Vanguard Portfolio Management LLC or business divisions of such affiliates: Vanguard Fiduciary Trust Company and Vanguard Global Advisers, LLC. This Schedule 13G includes securities held by Vanguard funds, or sleeves thereof, over which Vanguard Portfolio Management LLC exercises dispositive power, in addition to securities held by clients over which the affiliates or business divisions of such affiliates indicated above exercise dispositive and/or voting power. This Schedule 13G does not include securities, if any, beneficially owned by other subsidiaries or affiliates of Vanguard Portfolio Management LLC, or business divisions of such subsidiaries whose ownership of securities is disaggregated from that of the reporting business unit in accordance with such release.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: American Tower Corp
(b)	Address of issuer's principal executive offices: 116 Huntington Avenue, 11th Floor, Boston, MA, 02116
Item 2.
(a)	Name of person filing: Vanguard Portfolio Management
(b)	Address or principal business office or, if none, residence: 100 Vanguard Blvd,, Malvern, PA, 19355
(c)	Citizenship: PA
(d)	Title of class of securities: Common Stock
(e)	CUSIP Number(s): 03027X100
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 27718958
(b)	Percent of class: 5.94 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 122799
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 27718958
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. Vanguard Portfolio Management, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities reported herein.No one other person's interest in the securities reported herein is more than 5%.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Vanguard Portfolio Management

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	04/28/2026

FAQ

How many American Tower (AMT) shares does Vanguard Portfolio Management report owning?

Vanguard reports beneficial ownership of 27,718,958 shares of American Tower common stock. This position is labeled as 5.94% of the class and is reported as of 03/31/2026.

Does Vanguard have voting control over the AMT shares it reports?

The filing shows Vanguard has sole voting power for 122,799 shares and sole dispositive power for 27,718,958 shares, indicating control over disposition but limited direct voting authority on most reported shares.

Are these shares held on behalf of Vanguard funds or other clients?

Yes. The filing states the shares are held by Vanguard Portfolio Management LLC and affiliated entities, and include securities held by Vanguard funds and managed accounts over which Vanguard exercises dispositive power.

What date does the Schedule 13G position reflect for AMT ownership?

The ownership position is reported with an as of date of 03/31/2026. The signature block shows the filing was signed on 04/28/2026.

Does the Schedule 13G indicate any other person holds more than 5% of AMT through Vanguard?

The filing states that no single other person's interest reported here exceeds 5%. It notes that shareholders of registered investment companies are not individually listed.