The Federal Bureau of Investigation and the Securities and Exchange Commission are investigating possible insider trading involving billionaire investor Carl Icahn, golfer Phil Mickelson and Las Vegas gambler William Walters, a source familiar with the matter told Reuters....Federal investigators are looking into whether Mickelson and Walters may have traded illegally on private information provided by Icahn about his investments in public corporations, the source told Reuters, confirming a report by the Wall Street Journal on Friday.
Icahn, Mickelson and Walters were not immediately available for comment. Spokespeople for the FBI and SEC declined to comment.
The investigation is the latest case to emerge from a multiyear crackdown by U.S. authorities on insider trading. It involves two of the highest-profile personalities in finance and sport: famously combative activist investor Icahn and multiple Masters champion Mickelson.
Walters, who plays golf with Mickelson, is a well-known sports bettor who met Icahn through a mutual acquaintance and struck up a friendship, according to the Journal.
All I know is that Phil is one of the nicest guys in sports - he has arguably done as much for golf as Tiger. I'm shocked at this point and certainly hope these allegations aren't true. Couldn't happen to a kinder gentleman, if you ask me.... And remember, folks - the man is innocent until proven guilty.

Read more here: Icahn, Mickelson Investigated in Insider Trading Case - NBC News