By Stephen Evans North America Business Correspondent

One of America's biggest supermarket chains, Kmart, is being investigated by the Federal Bureau of Investigation (FBI).

Kmart loaned one of its executives $30m just before the company filed for bankruptcy in January.

The FBI said it was looking at the loan to see if any crime had been committed.

The allegation is that money was funnelled from the firm just before the filing.

"The FBI is looking at the situation at Kmart to determine any possible violations for criminal prosecution at a later time," said FBI agent Dawn Clenney.

The investigation was launched soon after the group of discount stores restated its 2001 net loss.

It is now saying it lost $2.42bn, having originally reported losses of just $244m.

Breakdown of trust

K-Mart, which is already being investigated by the financial sector watchdog Securities and Exchange Commission, joins a long line of companies now being investigated by the authorities.

Energy companies are being investigated as well to see whether they held back power supplies in California to push up prices when there were blackouts last summer.

Two telecoms firms are being investigated for pretending to trade with each other so their revenue seemed higher than they actually were.

Wall Street banks are being investigated to see whether they followed Merrill Lynch's practice of advising the public to do one thing while believing the opposite.

All of this matters because a breakdown of trust would dent stock markets seriously.