THE Securities and Exchange Commission (SEC) is investigating fund managers at the biggest US mutual fund company to see if they used their trading power to make personal profit, the Washington Post reported yesterday.

The newspaper quoted government and legal sources as saying the SEC was looking at the personal trading accounts of at least three Fidelity Investments fund managers and Mr Jeffrey Vinik, who runs the $56 billion(£35.7 billion) Magellan Fund.

The newspaper also said the SEC was looking at the trading of three former Fidelity employees, a former fund manager and two former analysts while they were at the firm.

It said the SEC was trying to determine whether they traded stocks for themselves to benefit from subsequent buying or selling by Fidelity mutual funds, a practice known as "front-running". Fidelity manages some $428 billion for about 10 million customers.