X0303 4 2011-01-14 0001278021 MARKETAXESS HOLDINGS INC MKTX 0001296468 Themelis Nicholas C/O MARKETAXESS HOLDINGS INC. 299 PARK AVENUE NEW YORK NY 10171 0 1 0 0 Chief Information Officer Common Stock, par value $0.003 per share 2011-01-14 4 A 0 18689 0 A 138584 D Common Stock, par value $0.003 per share 2011-01-14 4 F 0 17529 21.59 D 121055 D Represents a grant of restricted stock units pursuant to the Company's 2004 Stock Incentive Plan (Amended and Restated Effective April 28, 2006). The restricted stock units will vest in three equal annual installments, beginning on January 15, 2012. Represents the surrender of shares to the Company to satisfy Mr. Themelis' tax withholding obligation upon the vesting of shares of restricted stock previously granted to Mr. Themelis. /s/ Ori Solomon, as Attorney-in-Fact for Nicholas Themelis 2011-01-19