The poster child for the high frequency trading opposition to the Michael Lewis book Flash Boys is stepping down as president of BATS Global Markets.

William O’Brien bats global

BATS Global Markets announced the departure of William O’Brien

In a press release today, BATS “announced the departure of William O’Brien as President, effective immediately, with CEO Joe Ratterman reassuming the additional role of President.”

The brief press release did not mention O’Brien other to say he was leaving. When contacted about the potential for O’Brien’s exit being tied to negative publicity or the recent investigation of HFT by New York Attorney General Eric Schneiderman, sources inside the exchange would not comment on or off the record.

O’Brien had been at BATS for six years and witnessed the rise of HFT. He joined the exchange after it merged with Direct Edge, where he had served as its CEO, the Wall Street Journal noted. Previous to that O’Brien had worked at the NASDAQ.

BATS was originally created by large banks and brokerage firms with the goal to take business away from the then dominate New York Stock Exchange. Critics claim it had cozied up to the high frequency trading world and provided the trading practice undue favor.

O’Brien was considered to be a lightening rod

O’Brien was considered by some to be a lightening rod, as it was O’Brien who so vocally launched into a full throttle attack of Micheal Lewis, his book and the IEX Exchange that was the featured hero in Flash Boys .

As previously reported in ValueWalk, the fight between O’Brien and IEX Exchange founder Brad Katsuyama, broadcast on CNBC, is considered the most memorable knock-down, drag out fights in the history of business television.

The fight featured O’Brien appearing to almost jump out of his seat to attack Katsuyama, who was sitting next to him on CNBC’s New York Stock Exchange set.

“Shame on both of you for accusing literally thousands of [HFT related] people and scaring millions of investors in an effort to promote a business model,” O’Brien said, addressing Katsuyama.  “It’s a very, very old tactic to try to build a business on the planks of fear, mistrust and accusation,” continued O’Brien, an attacking tone in his voice while he looked Katsuyama in the eye as he sat next to him on CNBC’s lower Manhattan set floor of the New York Stock Exchange.  Even by trading standards, this fight was a donnybrook to remember – and its emotion is a sign of the important stakes that are in play for the exchange world, a topic that hasn’t received much attention, was ValueWalk’s report at the time.

To re-live the entire event, visit: Flash Boys Fight On CNBC Reveals Emotions Behind High Stakes Battle