[Form 4] MarketAxess Holdings Inc. Insider Trading Activity

Rhea-AI Filing Summary

MarketAxess Holdings Inc. (MKTX) director Stephen P. Casper reported sales of company common stock on 09/08/2025. The Form 4 shows a sale of 1,600 shares at $186.59, and a separate disposition of 9,985 shares. After the reported transactions, Casper is shown as beneficially owning 43,208 shares indirectly through a family trust. The filing is signed by an attorney-in-fact on 09/09/2025.

Positive

• None.

Negative

• Director disposed of 11,585 shares on 09/08/2025 (1,600 shares at $186.59 and a separate disposition of 9,985 shares), which could be perceived as insider selling activity

Insights

Financial Analyst

TL;DR Director sold shares in two transactions totaling 11,585 shares; remaining indirect holding is 43,208 shares.

The transactions reported on Form 4 are routine insider dispositions. The sale of 1,600 shares had an explicit per-share price of $186.59; the separate disposition of 9,985 shares is reported without a listed price in the provided text. The director retains indirect beneficial ownership of 43,208 shares via a family trust, which remains material to insider alignment but the filing alone does not indicate broader corporate changes.

Corporate Governance Expert

TL;DR Disclosure shows compliance with Section 16 reporting; underlying motives for sales are not disclosed.

The Form 4 documents timely reporting of changes in beneficial ownership by a director. The filing confirms indirect ownership through a family trust and records two dispositions on 09/08/2025. There is no supplemental information on any 10b5-1 plan or other arrangements in the provided content, so governance implications are limited to transparency of the trades.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
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hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Casper Stephen P

(Last) (First) (Middle)

C/O MARKETAXESS HOLDINGS INC.

55 HUDSON YARDS, 15TH FLOOR

(Street)

NEW YORK NY 10001

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
MARKETAXESS HOLDINGS INC [ MKTX ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
09/08/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock, par value $0.003 per share	09/08/2025		S		1,600	D	$186.59	43,208	I	By family trust
Common Stock, par value $0.003 per share								9,985	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

	/s/ Patrick Wilson, as Attorney-in-Fact for Stephen Casper	09/09/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did Stephen P. Casper report in the MKTX Form 4?

The Form 4 reports dispositions on 09/08/2025 of 1,600 shares sold at $186.59 and a separate disposition of 9,985 shares, with 43,208 shares beneficially owned indirectly via a family trust.

When were the transactions reported for MKTX insider Stephen Casper?

The transactions occurred on 09/08/2025 and the Form 4 was signed by an attorney-in-fact on 09/09/2025.

How many MKTX shares does Stephen Casper beneficially own after the reported transactions?

The filing shows 43,208 shares beneficially owned indirectly through a family trust following the reported transactions.

Was a sale price disclosed for all disposed MKTX shares?

A per-share price of $186.59 is disclosed for the 1,600-share sale; the provided content does not list a price for the 9,985-share disposition.

Does the Form 4 indicate the trades were made under a 10b5-1 plan?

The provided filing text does not indicate that the transactions were made pursuant to a 10b5-1 plan or similar written arrangement.