WASHINGTON The U.S. Securities and Exchange Commission (SEC) on Tuesday charged Concord Management and its owner with failing to register with regulators while operating as an investment adviser to their only client, an unnamed billionaire former Russian official.

Concord Management LLC of Tarrytown, New York, and owner Michael Matlin were operating as unregistered investment advisers to their client, a former Russian official with apparent connections to the Russian Federation, the SEC said in a statement.

A lawyer for Concord and Matlin did not respond immediately to requests for comment.

Over $7 billion of assets belonging to a single foreign individual was "actively managed" in U.S. markets by a single firm without regulatory oversight, the SEC said in its charges.

(Reporting by Chris Prentice in New York and Rammi Ayyub and Katharine Jackson in Washington; Editing by Caitlin Webber and Josie Kao)