Legendary duo takes different paths in high-frequency trading world

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 former employer paid a record fine to settle allegations with the Securities and Exchange Commission. (The charges stemmed from controversial “order types” at Direct Edge, which O’Brien ran prior to its acquisition by BATS.)

O’Brien declined to discuss rumors he’s in talks to take a major executive role at a firm that has significant bond trading. “I am not ready to do that yet,” O’Brien told The Post. “I haven’t talked [publicly] for some time. I am not ready to talk about anything now, and when I am I will let you know,” he added.

Meanwhile, at Credit Suisse’s regional headquarters in New York, colleagues were exchanging hugs with Mathisson. A beloved, mild-mannered math genius who ran all US stock trading as well as electronic trading, Mathisson officially departs late next month. He has told employees he’ll hit the beach and lay low for six months. Mathisson’s exit came as the Swiss bank announced plans to restructure its sprawling equity complex.

As part of that, the bank appointed Nas Al-khudairi to a new post, head of electronic products.

A Credit Suisse spokeswoman declined to discuss Mathisson’s next move, except to note published reports he plans to eventually start his own business outside of banking.