MARKETAXESS HOLDINGS INC

(a)Evaluation of Disclosure Controls and Procedures. Our management, including the Chief Executive Officer and the Chief Financial Officer, evaluated the effectiveness of our “disclosure controls and procedures,” as that term is defined in Rule 13a-15(e) and Rule 15d-15(e) promulgated under the Exchange Act, as of March 31, 2026. Based on that evaluation, the Chief Executive Officer and the Chief Financial Officer concluded that the disclosure controls and procedures are effective to ensure that information required to be disclosed by MarketAxess in the reports that we file or submit under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms, and to ensure that information is accumulated and communicated to our management, including the Chief Executive Officer and the Chief Financial Officer, as appropriate to allow timely decisions regarding required disclosure.

(b)Changes in Internal Control over Financial Reporting. There were no changes in our internal control over financial reporting (as defined in Rule 13a-15(f) and Rule 15d-15(f) under the Exchange Act) during the quarter ended March 31, 2026 identified in connection with the evaluation thereof by our management, including the Chief Executive Officer and the Chief Financial Officer, that materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.