Exhibit 99.1 MarketAxess Reports First Quarter 2024 Financial Results Record Emerging Markets, Eurobonds and Municipal Bonds Quarterly Commission Revenue NEW YORK | May 7, 2024—MarketAxess Holdings Inc. (Nasdaq: MKTX), the operator of a leading electronic trading platform for fixed-income securities, today announced financial results for the first quarter ended March 31, 2024. 1Q24 select financial and operational highlights* Chris Concannon, CEO of MarketAxess, commented: • Total revenues of $210.3 million ...