Vanguard holds 9.12% of CoStar Group

Vanguard Portfolio Management reported beneficial ownership of 38,292,035 shares of CoStar Group Inc Common Stock, representing 9.12% of the class.

Rhea-AI Filing Summary

Vanguard Portfolio Management reported beneficial ownership of 38,292,035 shares of CoStar Group Inc Common Stock, representing 9.12% of the class. The filing shows sole dispositive power for 38,292,035 shares and sole voting power for 57,902 shares. Vanguard states these holdings include securities held for Vanguard funds and managed accounts over which it or its affiliates exercise dispositive power. The filing is signed by Ashley Grim as Head of Global Fund Administration.

Key Figures

Beneficially owned shares: 38,292,035 shares Percent of class: 9.12% Sole voting power: 57,902 shares +2 more

5 metrics

Beneficially owned shares 38,292,035 shares Amount beneficially owned as reported on Schedule 13G

Percent of class 9.12% Percent of CoStar Group Common Stock represented by the reported holdings

Sole voting power 57,902 shares Shares over which Vanguard reports sole power to vote

Sole dispositive power 38,292,035 shares Shares over which Vanguard reports sole power to dispose or direct disposition

Filing signatory Signed 04/29/2026 Signature date on the Schedule 13G by Ashley Grim

Key Terms

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

4 terms

Schedule 13G regulatory

"Item 1. | (a) | Name of issuer: CoStar Group Inc"

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

"Item 4. | Ownership (a) | Amount beneficially owned: 38292035"

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.

dispositive power regulatory

"7 | Sole Dispositive Power 38,292,035.00"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

sole voting power regulatory

"5 | Sole Voting Power 57,902.00"

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.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stake does Vanguard (CSGP) report owning?

Vanguard reports beneficial ownership of 38,292,035 shares, equal to 9.12% of CoStar Group's common stock. This figure is the amount reported as under Vanguard's dispositive control in the Schedule 13G.

Does Vanguard have voting control of the CoStar shares?

Vanguard reports sole voting power over 57,902 shares and no shared voting power. The filing distinguishes voting authority from dispositive (sale) authority over the larger holding.

Who filed the Schedule 13G for CSGP on Vanguard's behalf?

The filing lists Vanguard Portfolio Management as the reporting person and is signed by Ashley Grim, Head of Global Fund Administration, with an effective signature date of 04/29/2026.

Are Vanguard's CoStar holdings held for funds or clients?

Yes. The filing states the holdings include securities held by Vanguard funds and managed accounts over which Vanguard Portfolio Management or affiliates exercise dispositive power. Beneficial owners within funds are not individually listed.

What percent threshold does this Schedule 13G indicate for ownership reporting?

The filing reports ownership at 9.12%, exceeding the 5% reporting threshold. That percentage is the disclosed percent of the class as of the Schedule 13G filing details.

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

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Accepted by SEC EDGAR 04/29/2026 - 12:51 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

CoStar Group Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

22160N109

(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): 22160N109

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 57,902.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 38,292,035.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

38,292,035.00

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)

9.12 %

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: CoStar Group Inc
(b)	Address of issuer's principal executive offices: 1201 Wilson Blvd, Arlington, VA, 22209
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): 22160N109
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: 38292035
(b)	Percent of class: 9.12 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 57902
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 38292035
	(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:	04/29/2026