WASHINGTON, Jan. 12 (Xinhua) -- The U.S. Securities and Exchange Commission (SEC) said on Monday that two stock exchanges formerly owned by Direct Edge Holdings have agreed to pay a 14- million-U.S.-dollar penalty to settle charges that their rules failed to accurately describe their order types.

The penalty marked the agency's largest against a national securities exchange and the case was the SEC's first principally focusing on stock exchange order types, the SEC said in a statement.

The SEC found that the EDGA exchange and the EDGX exchange, which have since been acquired by BATS Global Markets, offered three types of so-called "price sliding" orders from 2010 through 2014, but didn't "completely and accurately describe the prices at which those orders would be ranked and executable in certain circumstances."

The SEC also said the exchanges separately disclosed information about how those order types operated to some but not all of their members. "Exchanges must ensure their order types are described accurately in their rules and communications to all members," said Andrew Ceresney, director of the SEC's Division of Enforcement.

The exchanges neither admitted nor denied the SEC's findings, but agreed to refrain from such violations in the future and develop new policies regarding the order types.