BATS President William O'Brien leaves, CEO Joe Ratterman to assume duties

Joseph 'Joe' Ratterman, president and chief executive officer of BATS Global Markets Inc., looks on during a Senate Permanent Subcommittee on Investigations hearing in Washington, June 17, 2014.
Andrew Harrer | Bloomberg | Getty Images
Joseph 'Joe' Ratterman, president and chief executive officer of BATS Global Markets Inc., looks on during a Senate Permanent Subcommittee on Investigations hearing in Washington, June 17, 2014.

BATS Global Markets, a global operator of securities markets, announced in a release on Tuesday that its president, William O'Brien, has left the company.

CEO Joe Ratterman will reassume his role of President and CEO, a position the release said he had held from June 2007 to January 2014.

None of the other executive management are affected, the company said, without giving a reason for O'Brien's departure. The new roles were apparent on the BATS website immediately following the announcement.

The great debate: Combating HFTs image
The great debate: Combating HFTs image   

In an April CNBC segment, O'Brien challenged author Michael Lewis and IEX's Brad Katsuyama on their assertion that high-speed traders rigged the markets.

Read MoreWatch the fight that stopped trading at the NYSE

—By CNBC.com. Reuters contributed to this report.