MarketAxess (MKTX) DEFA14A Additional proxy soliciting materials

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No.        )

Filed by the Registrant þ

Filed by a Party other than the Registrant ¨

Check the appropriate box:

¨ Preliminary Proxy Statement

¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

¨ Definitive Proxy Statement

þ Definitive Additional Materials

¨ Soliciting Material Pursuant to § 240.14a-12

MarketAxess Holdings Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

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þ No fee required.

¨ Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.

(1) Title of each class of securities to which transaction applies:

(2) Aggregate number of securities to which transaction applies:

(3) Per unit price or other underlying value of transaction computed pursuant to Exchange Act Rule 0-11 (set forth the amount on which the filing fee is calculated and state how it was determined):

(4) Proposed maximum aggregate value of transaction:

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¨ Fee paid previously with preliminary materials.

¨ Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

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*** Exercise YourRight to Vote ***

Important Notice Regarding the Availability of Proxy Materials for the

Shareholder Meeting to Be Held on June 06, 2013

			Meeting Information
	MARKETAXESS HOLDINGS INC.		Meeting Type: Annual Meeting
			For holders as of:April 09, 2013
			Date: June 06, 2013	Time: 10:00 AM EDT
	MARKETAXESS HOLDINGS INC. 299 PARK AVENUE NEW YORK, NY 10171		Location:  InterContinental New York     Barclay Hotel     111 East 48th Street     New York, NY 10017
		You are receiving this communication because you hold shares in the above named company.
		This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. You may view the proxy materials online atwww.proxyvote.comor easily request a paper copy (see reverse side).
		We encourage you to access and review all of the important information contained in the proxy materials before voting.
			See the reverse side of this notice to obtain proxy materials and voting instructions.

	—  Before You Vote  — How to Access the Proxy Materials
	Proxy Materials Available to VIEW or RECEIVE:
	1. Notice & Proxy Statement    2. Form 10-K
	How to View Online:
	Have the information that is printed in the box marked by the arrow (located on the following page) and visit:www.proxyvote.com.
	How to Request and Receive a PAPER or E-MAIL Copy:
	If you want to receive a paper or e-mail copy of these documents, you must request one. There is NO charge for requesting a copy. Please choose one of the following methods to make your request:
	1)BY INTERNET:        www.proxyvote.com
	2)BY TELEPHONE:    1-800-579-1639
	3)BY E-MAIL*:            sendmaterial@proxyvote.com
	*   If requesting materials by e-mail, please send a blank e-mail with the information that is printed in the box marked by the arrow (located on the following page) in the subject line. Requests, instructions and other inquiries sent to this e-mail address will NOT be forwarded to your investment advisor. Please make the request as instructed above on or before May 23, 2013 to facilitate timely delivery.
	—  How To Vote  — Please Choose One of the Following Voting Methods
	Vote In Person:Many shareholder meetings have attendance requirements including, but not limited to, the possession of an attendance ticket issued by the entity holding the meeting. Please check the meeting materials for any special requirements for meeting attendance. At the meeting, you will need to request a ballot to vote these shares.
	Vote By Internet:To vote now by Internet, go towww.proxyvote.com.Have the information that is printed in the box marked by the arrow available and follow the instructions.
	Vote By Mail:You can vote by mail by requesting a paper copy of the materials, which will include a proxy card.

	Voting items
	The Board of Directors recommends you vote FOR the following:
	1.	Election of Directors
		Nominees
	01      02      03      04      05      06      07      08	Richard M. McVey Steven L. Begleiter Stephen P. Casper David G. Gomach Carlos M. Hernandez Ronald M. Hersch John Steinhardt James J. Sullivan	NOTE: UNLESS OTHERWISE SPECIFIED BY THE UNDERSIGNED, THIS PROXY WILL BE VOTED FOR THE ELECTION OF THE NOMINEES FOR DIRECTOR LISTED ABOVE AND FOR PROPOSALS 2 AND 3, AND WILL BE VOTED BY THE PROXYHOLDERS AT THEIR DISCRETION AS TO ANY OTHER MATTERS PROPERLY TRANSACTED AT THE MEETING OR AT ANY POSTPONEMENT OR ADJOURNMENT THEREOF. TO VOTE IN ACCORDANCE WITH THE BOARD OF DIRECTORS’ RECOMMENDATIONS, JUST SIGN BELOW - NO BOXES NEED BE CHECKED.
	The Board of Directors recommends you vote FOR the following proposal(s):
	2.	To ratify the appointment of PricewaterhouseCoopers LLP as the Company’s independent registered public accounting firm for the year ending December 31, 2013.
	3.	To approve, on an advisory basis, the compensation of the Company’s named executive officers as disclosed in the 2013 Proxy Statement.