The U.S. securities regulator has decided not to file civil charges against hedge fund firm Magnetar Capital LLC over its role in helping create mortgage securities that lost value during the financial crisis, the Wall Street Journal reported.

For more than a year, enforcement officials of the Securities and Exchange Commission (SEC) have been investigating whether Magnetar violated federal law over the selection of assets bundled in a collateralized debt obligation (CDO) called Norma CDO I that was created by Merrill Lynch & Co, now a unit of Bank of America Corp, the paper said.