In the high-speed world of high-frequency trading change comes quick, too, as Wall Street struggles to find seasoned execs to lead the firms’ efforts. Two legends of the electronic marts are moving in opposite directions: one going out, the other right back in, and potentially for a shot at bond market glory. As Credit Suisse confirmed the resignation of trading boss Daniel Mathisson, 45, the cheers went up for comeback exec William O’Brien, 44. The former BATS Global Markets president departed the firm in July 2014, soon after his epic shouting match with upstart rival IEX on CNBC — and just months before O’Brien’s ... (full story)