Graham Holdings (NASDAQ: PUBM) reports 8.9% stake in PubMatic after amendment

Rhea-AI Filing Summary

Graham Holdings Company files an Amendment to Schedule 13G/A reporting beneficial ownership in PubMatic, Inc. The filing states Graham Holdings beneficially owns 3,398,904 shares of PubMatic Class A common stock, representing 8.9% of the class. The percentage is calculated using 38,180,751 shares outstanding as of April 30, 2026, per PubMatic's Form 10-Q. The filing is signed by Nicole Maddrey, Senior Vice President, Secretary, General Counsel, dated May 15, 2026.

Key Figures

Beneficial ownership: 3,398,904 shares Percent of class: 8.9% Shares outstanding: 38,180,751 shares +2 more

5 metrics

Beneficial ownership 3,398,904 shares Amount beneficially owned reported on Schedule 13G/A

Percent of class 8.9% Percent of Class A common stock based on outstanding shares as of April 30, 2026

Shares outstanding 38,180,751 shares Shares outstanding used to calculate percentage, as of April 30, 2026

CUSIP 74467Q103 PubMatic Class A Common Stock CUSIP on the filing cover

Signature date May 15, 2026 Date the amendment was signed by Graham Holdings' counsel

Key Terms

Schedule 13G/A, beneficially owned, sole dispositive power

3 terms

Schedule 13G/A regulatory

"Amendment No. 2 ) PubMatic, Inc. Class A Common Stock"

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.

beneficially owned financial

"Item 4. | Ownership (a) | Amount beneficially owned: 3,398,904"

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

"7 | Sole power to dispose or to direct the disposition of: 3,398,904"

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.

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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 2)

PubMatic, Inc.

(Name of Issuer)

Class A Common Stock, par value $0.0001 per share

(Title of Class of Securities)

74467Q103

(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): 74467Q103

1

Names of Reporting Persons

Graham Holdings Company

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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 3,398,904.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 3,398,904.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,398,904.00

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)

8.9 %

12

Type of Reporting Person (See Instructions)

CO

Comment for Type of Reporting Person: In reference to #11, the percentage ownership is calculated based upon an aggregate of 38,180,751 shares of Class A common stock outstanding as of April 30, 2026, as reported in PubMatic, Inc.'s Form 10-Q filed on May 7, 2026.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: PubMatic, Inc.
(b)	Address of issuer's principal executive offices: 601 Marshall Street, Redwood City, California, 94063
Item 2.
(a)	Name of person filing: Graham Holdings Company
(b)	Address or principal business office or, if none, residence: 1812 North Moore Street, Suite 2100, Arlington, VA 22209
(c)	Citizenship: Graham Holdings Company is incorporated in the State of Delaware.
(d)	Title of class of securities: Class A Common Stock, par value $0.0001 per share
(e)	CUSIP No.: 74467Q103
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: 3,398,904
(b)	Percent of class: 8.9%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 3,398,904
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 3,398,904
	(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.
	Not Applicable
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 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.

Graham Holdings Company

Signature:	/s/ Nicole Maddrey
Name/Title:	Nicole Maddrey, Senior Vice President, Secretary, General Counsel
Date:	05/15/2026

FAQ

What stake did Graham Holdings disclose in PubMatic (PUBM)?

Graham Holdings disclosed beneficial ownership of 3,398,904 shares, equal to 8.9% of PubMatic Class A common stock. This percentage uses 38,180,751 shares outstanding as of April 30, 2026, as reported in PubMatic's Form 10-Q.

What date is the ownership percentage based on in the PubMatic Schedule 13G/A amendment?

The ownership percentage is based on 38,180,751 shares outstanding as of April 30, 2026. That outstanding-share count is cited verbatim in the filing and comes from PubMatic's Form 10-Q filed May 7, 2026.

Who signed the Schedule 13G/A amendment for Graham Holdings and when?

The amendment is signed by Nicole Maddrey, Senior Vice President, Secretary, General Counsel, on May 15, 2026. The signature block appears at the end of the filing and identifies her title and date.

Does the filing state how Graham Holdings acquired the PubMatic shares or any planned transactions?

The filing lists beneficial ownership and voting/dispositive powers but does not describe acquisition method or planned sales. It states Graham Holdings has sole voting and dispositive power over 3,398,904 shares without transaction details.