The divergent lives of a championship golfer, a high-rolling gambler and a billionaire investor have collided in a federal insider trading investigation.

Federal authorities are examining a series of well-timed trades belonging to golfer Phil Mickelson and gambler William T. Walters, people briefed on the investigation said, focusing on trading in two stocks. The authorities are also questioning what role, if any, investor Carl Icahn may have had in sharing information about one of the stocks: consumer products company Clorox.

Mickelson, a three-time winner of the Masters and one of the country’s highest-earning athletes, placed his Clorox trade in 2011, the people briefed on the investigation said. Walters, an owner of golf courses who is often considered the most successful sports bettor in the country, made a similar trade about that time, the people added.

Icahn, a 78-year-old billionaire and one of the best-known investors in the world, was mounting a takeover bid for Clorox around the time that Mickelson and Walters placed their trades.

The FBI and Securities and Exchange Commission are examining whether Icahn leaked details of his Clorox bid to Walters, the people briefed on the investigation said. One theory, the people said, is that Walters might have passed on that information to Mickelson.