Vanguard Portfolio Management (OMC) discloses 13.5M Omnicom shares in 13G/A

Rhea-AI Filing Summary

Vanguard Portfolio Management LLC, together with certain affiliates, reports beneficial ownership of 13,510,040 shares of Omnicom Group Inc. common stock on a Schedule 13G/A (Amendment No. 1) as of June 30, 2026.

This position represents 4.74% of Omnicom’s common stock. Vanguard has sole voting power over 32,036 shares and sole dispositive power over 13,510,040 shares, with no shared voting or dispositive power. The holdings include securities held by various Vanguard funds and managed accounts for which Vanguard-affiliated entities exercise dispositive and, in some cases, voting power. No single other person’s interest in these securities exceeds 5% of the class.

Key Figures

Beneficial Ownership: 13,510,040 shares Percent of Class: 4.74% Sole Voting Power: 32,036 shares +3 more

6 metrics

Beneficial Ownership 13,510,040 shares Shares of Omnicom Group Inc. common stock beneficially owned by Vanguard Portfolio Management

Percent of Class 4.74% Portion of Omnicom Group Inc. common stock class beneficially owned

Sole Voting Power 32,036 shares Shares over which Vanguard Portfolio Management has sole power to vote

Shared Voting Power 0 shares Shares over which Vanguard Portfolio Management has shared voting power

Sole Dispositive Power 13,510,040 shares Shares over which Vanguard Portfolio Management has sole power to dispose

Shared Dispositive Power 0 shares Shares over which Vanguard Portfolio Management has shared dispositive power

Key Terms

beneficially owned, sole voting power, sole dispositive power, Schedule 13G/A, +1 more

5 terms

beneficially owned financial

"this reflects the securities beneficially owned, or deemed to be beneficially owned, by Vanguard"

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 voting power financial

"Sole Voting Power 32,036.00"

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.

sole dispositive power financial

"Sole Dispositive Power 13,510,040.00"

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.

Schedule 13G/A regulatory

"reports beneficial ownership of Omnicom Group Inc. on a Schedule 13G/A"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

percent of class financial

"Percent of class: 4.74 %"

Percent of class is the portion of a specific category of securities—such as a company’s common shares, preferred shares, or a bond series—that takes part in or approves a corporate action (vote, consent, tender, etc.). Investors watch this number because it reveals how much support or opposition exists within that particular shareholder group; like counting how many members of a club back a proposal, it can determine whether a plan passes or how influence is distributed.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 07/31/2026 - 11:23 AM Accepted by SEC EDGAR 07/31/2026 - 11:23 AM Learn about SEC filing dates

FAQ

What percentage of Omnicom Group Inc (OMC) does Vanguard Portfolio Management own?

Vanguard Portfolio Management reports beneficial ownership of 4.74% of Omnicom Group Inc. common stock. This stake is disclosed on a Schedule 13G/A and reflects shares held across Vanguard funds and other managed accounts under its dispositive control.

How many Omnicom Group Inc (OMC) shares does Vanguard Portfolio Management beneficially own?

Vanguard Portfolio Management beneficially owns 13,510,040 Omnicom Group Inc. common shares. These include securities held by Vanguard funds and other clients where Vanguard-affiliated entities exercise dispositive and, in some cases, voting power over the shares.

What voting power does Vanguard have over its Omnicom Group Inc (OMC) shares?

Vanguard Portfolio Management has sole voting power over 32,036 shares of Omnicom Group Inc. It reports no shared voting power, indicating that most of its reported holdings are not subject to Vanguard’s voting authority.

What dispositive power does Vanguard report over Omnicom Group Inc (OMC) shares?

Vanguard Portfolio Management reports sole dispositive power over 13,510,040 shares of Omnicom Group Inc. It has no shared dispositive power, meaning decisions to sell or otherwise dispose of these shares rest solely with Vanguard-affiliated entities.

Does any other single investor hold more than 5% interest in Vanguard’s Omnicom Group Inc (OMC) shares?

No. Vanguard states that no one other person's interest in the Omnicom Group Inc. securities it reports exceeds 5% of the class. The economic interests are spread across investment companies and other managed accounts.

Which Vanguard entities are included in the Omnicom Group Inc (OMC) 13G/A filing?

The reported holdings include securities beneficially owned or deemed owned by Vanguard Portfolio Management LLC and affiliates, including Vanguard Fiduciary Trust Company and Vanguard Global Advisers, LLC, as well as certain Vanguard funds and managed accounts.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Omnicom Group Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

681919106

(CUSIP Number)

06/30/2026

(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): 681919106

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 32,036.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 13,510,040.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

13,510,040.00

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)

4.74 %

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: Omnicom Group Inc
(b)	Address of issuer's principal executive offices: 280 Park Ave, New York, NY, 10017
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 No.: 681919106
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: 13510040
(b)	Percent of class: 4.74 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 32036
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 13510040
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
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:	My Trieu-Gatt
Name/Title:	Authorized Signatory, Head of Global Fund Administration
Date:	07/31/2026