MarketAxess (MKTX): AQR Capital discloses 1.99M-share, 5.59% ownership stake

Rhea-AI Filing Summary

AQR Capital Management, LLC and its parent AQR Capital Management Holdings, LLC report beneficial ownership of 1,987,288 shares of MarketAxess Holdings Inc. common stock, representing 5.59% of the class.

Both entities report shared voting power over 1,947,559 shares and shared dispositive power over 1,987,288 shares, with no sole voting or dispositive power. AQR Capital Management, LLC is a wholly owned subsidiary of AQR Capital Management Holdings, LLC.

Key Figures

Beneficially owned shares: 1,987,288 shares Percent of class: 5.59% Shared voting power: 1,947,559 shares +2 more

5 metrics

Beneficially owned shares 1,987,288 shares Common stock of MarketAxess beneficially owned by AQR entities

Percent of class 5.59% Portion of MarketAxess common stock class reported as owned

Shared voting power 1,947,559 shares Shares of MarketAxess over which AQR reports shared voting power

Shared dispositive power 1,987,288 shares Shares of MarketAxess over which AQR reports shared dispositive power

Par value per share $0.003 per share Par value of MarketAxess common stock class reported

Key Terms

beneficially owned, shared voting power, shared dispositive power, parent holding company, +1 more

5 terms

beneficially owned financial

"Item 4. | Ownership (a) | Amount beneficially owned: 1,987,288"

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.

shared voting power financial

"Shared Voting Power 1,947,559.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

shared dispositive power financial

"Shared Dispositive Power 1,987,288.00"

parent holding company financial

"Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company"

wholly owned subsidiary financial

"AQR Capital Management, LLC is a wholly owned subsidiary of AQR Capital Management Holdings, LLC."

A wholly owned subsidiary is a company whose entire ownership is held by another company (the parent), so the parent controls decisions, operations, and finances. Think of it as a fully controlled branch that runs as its own legal entity but whose results flow straight into the parent’s financial statements; investors watch these structures because they affect consolidated revenue, risk exposure, and how profits, liabilities, and cash flow are allocated across the corporate group.

FAQ

What percentage of MarketAxess (MKTX) does AQR Capital report owning?

AQR Capital Management, LLC and its parent report beneficial ownership of 5.59% of the outstanding common stock of MarketAxess Holdings Inc., based on 1,987,288 shares of common stock they collectively report as beneficially owned.

How many MarketAxess (MKTX) shares does AQR Capital beneficially own?

AQR Capital reports beneficial ownership of 1,987,288 shares of MarketAxess common stock. This position represents 5.59% of the class, according to the Schedule 13G/A filing for the company’s $0.003 par value common stock.

Does AQR Capital have sole or shared voting power over its MKTX shares?

AQR Capital reports shared voting power over 1,947,559 shares of MarketAxess and no sole voting power. Voting authority over these shares is therefore reported as shared between the filing entities rather than individually controlled.

What dispositive power does AQR Capital report over MarketAxess (MKTX) shares?

AQR Capital and its parent report shared dispositive power over 1,987,288 shares of MarketAxess common stock and no sole dispositive power. Dispositive power refers to the authority to dispose of or direct the disposition of the securities.

Which entities filed the Schedule 13G/A for MarketAxess (MKTX)?

The filing was made jointly by AQR Capital Management, LLC and AQR Capital Management Holdings, LLC. AQR Capital Management, LLC is described as a wholly owned subsidiary of AQR Capital Management Holdings, LLC in the accompanying exhibit.

Where are the AQR entities that hold MarketAxess (MKTX) shares organized and based?

Both AQR Capital Management, LLC and AQR Capital Management Holdings, LLC are organized in the United States, with their principal business office at One Greenwich Plaza, Suite 130, Greenwich, Connecticut 06830, according to the ownership filing.

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Available on EDGAR 08/13/2026 - 11:13 AM Accepted by SEC EDGAR 08/13/2026 - 11:13 AM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

MARKETAXESS HOLDINGS INC

(Name of Issuer)

Common Stock, $0.003 par value

(Title of Class of Securities)

57060D108

(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): 57060D108

1

Names of Reporting Persons

AQR Capital Management, LLC

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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,947,559.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,987,288.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,987,288.00

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)

5.59 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

CUSIP Number(s): 57060D108

1

Names of Reporting Persons

AQR Capital Management Holdings, LLC

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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,947,559.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,987,288.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,987,288.00

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)

5.59 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

Item 1.
(a)	Name of issuer: MARKETAXESS HOLDINGS INC
(b)	Address of issuer's principal executive offices: 55 HUDSON YARDS, 15TH FLOOR, NEW YORK, NEW YORK 10001
Item 2.
(a)	Name of person filing: AQR Capital Management, LLC AQR Capital Management Holdings, LLC
(b)	Address or principal business office or, if none, residence: ONE GREENWICH PLAZA SUITE 130 Greenwich, Connecticut 06830
(c)	Citizenship: AQR Capital Management, LLC - UNITED STATES AQR Capital Management Holdings, LLC - UNITED STATES
(d)	Title of class of securities: Common Stock, $0.003 par value
(e)	CUSIP No.: 57060D108
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: 1,987,288
(b)	Percent of class: 5.59 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: AQR Capital Management, LLC - 0 AQR Capital Management Holdings, LLC - 0
	(ii) Shared power to vote or to direct the vote: AQR Capital Management, LLC - 1,947,559 AQR Capital Management Holdings, LLC - 1,947,559
	(iii) Sole power to dispose or to direct the disposition of: AQR Capital Management, LLC - 0 AQR Capital Management Holdings, LLC - 0
	(iv) Shared power to dispose or to direct the disposition of: AQR Capital Management, LLC - 1,987,288 AQR Capital Management Holdings, LLC - 1,987,288
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.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. See Item 2(a) above.
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.

AQR Capital Management, LLC

Signature:	Henry Parkin
Name/Title:	Authorized Signatory
Date:	08/13/2026

AQR Capital Management Holdings, LLC

Signature:	Henry Parkin
Name/Title:	Authorized Signatory
Date:	08/13/2026

Exhibit Information

AQR Capital Management Holdings, LLC and AQR Capital Management, LLC hereby agree that this Schedule 13G is filed on behalf of each of the parties. AQR Capital Management, LLC is a wholly owned subsidiary of AQR Capital Management Holdings, LLC.