CBOE HoldingsInc. is in discussions to buy Bats Global Markets Inc., Bloomberg News reported aftermarkets closed Sept. 22, citing people familiar with the matter.

The deal could close within the next few weeks, but it hasnot been finalized and may not go through, according to the report.Shares of Bats soared more than 20% in after-hours trading, while shares ofCBOE were little changed.

The tie-up would join the primary options venue in the U.S.with the newest publicly traded equities exchange, less than a year after Batscompleted its IPO.  

CBOE's market capitalization was about $5.68 billion, whileBats' was about $2.58 billion, at the close of regular hours trading Sept. 22.