No evidence was found that Mickelson was involved in questionable stock trading in shares of Clorox, multiple sources told the New York Times.
Mickelson remains under investigation over well-timed trades involving Dean Foods stock that netted him nearly $1 million, according to New York Times sources.
"I'll continue to say, I haven't done anything wrong," Mickelson said after shooting a 70 in the first round of the U.S. Open on Thursday. "I'm willing to help out, love to help out any way on the investigation. So like I said before, with an investigation going on, I'm not going to comment any further on it. But I'll continue to say that I've done absolutely nothing wrong.''
The Wall Street Journal previously had reported that Mickelson was being investigated by FBI and SEC agents in an insider-trading case allegedly involving investor Carl Icahn and Las Vegas gambler Billy Walters. Officials reportedly analyzed trades Mickelson and Walters made involving Clorox in 2011, at the same time Icahn was attempting to take over the company. When Icahn's intent became public, the stock price jumped.
As far as Dean Foods, the New York Times reported that authorities are pursuing a theory that a source tipped Walters off about the company's plan to offer its WhiteWave Foods subsidiary in an initial public offering in 2012. It is unclear what prompted Walters and Mickelson to trade; however, shares of Dean Foods went up 41 percent the day after the company officially announced the news. Icahn is not connected to the Dean Foods trading.
Mickelson has denied any wrongdoing in either instance. No charges have been filed.
ESPN.com's Bob Harig contributed to this report.