BlackRock discloses 10.9% MarketAxess (MKTX) stake in amended 13G

Rhea-AI Filing Summary

BlackRock, Inc. filed an amended Schedule 13G disclosing beneficial ownership of 4,034,537 shares of MarketAxess Holdings Inc common stock, representing 10.9% of the class as of the event date.

BlackRock reports sole voting power over 3,958,354 shares and sole dispositive power over 4,034,537 shares. The filing states the securities were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control of MarketAxess. One holder, iShares Core S&P Small-Cap ETF, has an interest in more than five percent of MarketAxess common stock.

Insights

Equity ownership & governance analyst

BlackRock reports a 10.9% passive stake in MarketAxess.

BlackRock, Inc. discloses beneficial ownership of 4,034,537 MarketAxess common shares, or 10.9% of the class. It has sole voting power over 3,958,354 shares and sole dispositive power over 4,034,537 shares, reflecting significant institutional ownership concentration.

The certification states the position is held in the ordinary course of business and not to change or influence control, characterizing this as a passive stake. The filing also notes that iShares Core S&P Small-Cap ETF alone has an interest exceeding five percent of MarketAxess common stock.

For governance dynamics, this means MarketAxess has a large institutional holder with substantial voting power but a declared non‑control intent as of the 01/31/2026 event date. Future ownership updates may further detail shifts among BlackRock’s reporting business units.

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

(Title of Class of Securities)

57060D108

(CUSIP Number)

01/31/2026

(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)

SCHEDULE 13G

CUSIP No. 57060D108

1

Names of Reporting Persons

BlackRock, Inc.

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 3,958,354.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 4,034,537.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,034,537.00

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)

10.9 %

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 NY 10001
Item 2.
(a)	Name of person filing: BlackRock, Inc. 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 certain business units (collectively, the "Reporting Business Units") of BlackRock, Inc. and its subsidiaries and affiliates. It does not include securities, if any, beneficially owned by other business units whose beneficial ownership of securities are disaggregated from that of the Reporting Business Units in accordance with such release.
(b)	Address or principal business office or, if none, residence: BlackRock, Inc., 50 Hudson Yards New York, NY 10001
(c)	Citizenship: See Item 4 of Cover Page
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 57060D108
Item 4.	Ownership
(a)	Amount beneficially owned: 4034537
(b)	Percent of class: 10.9 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 3958354
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 4034537
	(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. The interest of 1 such person, iShares Core S&P Small-Cap ETF, in the common stock of MarketAxess Holdings Inc is more than five percent of the total outstanding common stock.
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 Exhibit 99
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.

BlackRock, Inc.

Signature:	Spencer Fleming
Name/Title:	Managing Director
Date:	02/06/2026

Exhibit Information

Exhibit 24: Power of Attorney Exhibit 99: Item 7

FAQ

How large is BlackRock’s ownership stake in MarketAxess (MKTX)?

BlackRock, Inc. reports beneficial ownership of 4,034,537 shares of MarketAxess Holdings Inc common stock, representing 10.9% of the class. BlackRock has sole voting power over 3,958,354 shares and sole dispositive power over 4,034,537 shares, indicating significant institutional ownership concentration.

Is BlackRock’s MarketAxess (MKTX) stake classified as passive or active?

BlackRock certifies its MarketAxess holdings are acquired and held in the ordinary course of business and not for changing or influencing control. The filing states the securities are not held in connection with any transaction having that purpose or effect, indicating a passive ownership posture.

What voting and dispositive powers does BlackRock have over MarketAxess shares?

BlackRock reports sole power to vote or direct the vote for 3,958,354 shares and sole power to dispose or direct the disposition of 4,034,537 shares. It reports no shared voting power and no shared dispositive power over MarketAxess common stock.

Which BlackRock-related entity holds over 5% of MarketAxess common stock?

The filing notes that iShares Core S&P Small-Cap ETF has an interest in MarketAxess common stock that is more than five percent of the total outstanding common stock. This reflects a substantial position within a specific BlackRock-affiliated exchange-traded fund.

What is the key event date for BlackRock’s MarketAxess ownership disclosure?

The event that triggered this ownership disclosure occurred on 01/31/2026. As of that date, BlackRock, Inc. beneficially owned 4,034,537 shares of MarketAxess common stock, representing 10.9% of the class, according to the amended Schedule 13G filing.

Who signed the BlackRock Schedule 13G/A filing for MarketAxess (MKTX)?

The amended Schedule 13G for MarketAxess was signed by Spencer Fleming, identified as a Managing Director at BlackRock, Inc. The signature certifies, after reasonable inquiry, that the information provided regarding ownership and control intent is true, complete, and correct.