NEW YORK, Dec 3 (Reuters) - Virtu Financial VIRT.N will pay a $2.5 million fine to settle U.S. Securities and Exchange Commission accusations the large market maker improperly allowed almost all employees at its broker-dealer unit access to confidential information about customers and their trades.

The broker-dealer unit Virtu Americas, which according to the SEC handled about 25% of market orders from U.S. retail investors during the relevant period, did not admit or deny wrongdoing, the SEC said on Wednesday. U.S. District Judge John Koeltl in Manhattan approved the accord.

In a civil complaint filed in September 2023, the SEC said Virtu repeatedly told customers that it used "information barriers" and "systemic separation between business groups" to protect their material nonpublic information.

The SEC said that was false, because broker-dealer employees were able from January 2018 to April 2019 to access customers' names, and the names, prices and volumes of securities that customers bought and sold, by using a "widely known and frequently shared generic user name and password."

Virtu, based in Manhattan, had no immediate comment on the settlement.

It has said it voluntarily disclosed to the SEC in 2019 that trade data may have been accessible to more employees than intended, and that it coincided with a migration of a recently acquired business into a back-office database.

(Reporting by Jonathan Stempel in New York; Editing by Lincoln Feast.)

((jon.stempel@thomsonreuters.com ; +1 646 223 6317; Reuters Messaging: jon.stempel.thomsonreuters.com@reuters.net /))