US golfer Mickelson denies insider trading wrongdoing
US golfer Phil Mickelson has denied any wrongdoing after the FBI launched an insider trading investigation.
The golfer, one of the US's richest and most-admired sportsmen, said he was co-operating with the government inquiry.
Mr Mickelson, investor Carl Icahn and William Walters, a high-profile gambler, are being investigated for possible illegal share sales, using information given by Mr Icahn.
Mr Icahn has also denied doing anything wrong. Mr Walters has yet to comment.
A source familiar with the investigation, quoted by the Reuters news agency, said none of the men had so far been accused of any wrongdoing.
The FBI, along with the Securities and Exchange Commission and federal prosecutors in Manhattan, are said to be looking into trading in two different stocks.
One line of inquiry is focusing on trades in cleaning products company Clorox.
Mr Icahn, a billionaire investor and prominent activist, was mounting a takeover bid for Clorox around the time that Mr Mickelson and Mr Walters placed their trades, the New York Times reports.
Mr Icahn's offer to buy the company caused the value of its stock to rise.
According to reports in several US newspapers, investigators are examining whether Mr Icahn discussed his bid with Mr Walters, and whether Mr Walters relayed that information to Mr Mickelson.
A lawyer for Mr Mickelson, quoted in the Wall Street Journal, said the golfer was not the target of the probe.
The statement from Mr Mickelson, denying wrongdoing, said he could not fully discuss the matter "under the current circumstances".
Practising before a tournament on Saturday, Mr Mickelson made a jovial reference to the investigation in a conversation with fellow US golfer, Robert Garrigus.
"It's been an interesting evening," the Reuters news agency quoted him as saying. "I don't have much to say about it."
After his round, Mr Mickelson confirmed he had been approached by FBI agents and said: "It's not going to change the way I carry myself. Honestly, I've done nothing wrong. I'm not going to walk around any other way."
Mr Mickelson, 43, has won five major championships and is one of the most popular figures in US golf.
Investigators are also reportedly looking into trades that Mr Mickelson and Mr Walters made relating to Dean Foods, the Wall Street Journal reports (pay wall).
The New York Times quotes sources saying federal authorities are looking into trades placed in August 2012 just before the company announced quarterly results.
Those trades appeared to have no connection to Mr Icahn, the newspaper added.
The FBI and other federal agencies have not commented publicly on the allegations.