Usana's stock jumped $13.91 to close at $49.48 for a 40 percent gain for the day.

"We couldn't have asked for a better outcome," said Joe Poulos, an outside spokesman for the Utah-based vitamin maker that markets its products using a multilevel distribution system. "This really is a vindication of the company."

The SEC began its "informal" investigation of Usana in March after an independent California-based investigator of corporate fraud targeted the company in a report that was cited in The Wall Street Journal's well-known "Heard on the Street" column.

Barry Minkow, an investigator who spent time in prison for securities and tax fraud but now runs a business known as the Fraud Discovery Institute, contended Usana's business model is "primarily based upon sales to a continuously collapsing pool of associates that need to be replaced monthly and yearly."

Minkow said Friday he is sticking with his position.

"This is the first time that the SEC and I have ever disagreed on the outcome [of one of their investigations]," Minkow said. "Heck, I even agreed with the SEC's action against me when I was a crook."

Minkow said he continues to believe that most people never make money becoming independent distributors of Usana's products. "Yet most people sign up thinking they're going to make money."

Usana responded by blasting Minkow's report and filing a lawsuit against him. It also pointed out that Minkow shorted the company's stock, claiming the investigator attempted to take advantage of the decline in the share price his allegations generated.

"We're still pursing that lawsuit," Poulos said.

Usana President David Wentz said in a statement Friday the company's management has "always been confident about the integrity of our company and takes pride in our direct-selling business model."

Under multilevel marketing arrangements, independent sales associates can earn a commission on merchandise they sell. More importantly, they get a piece of the sales from new distributors they recruit, and on down the line.

The company's announcement that it had received notification from the SEC that the inquiry was complete and that no "enforcement action" was being recommended, sparked a flurry of activity among analysts who follow Usana.

"A company that has just emerged from a SEC inquiry unscathed is likely a very clean company - and that has always been our view," said Timothy Ramey of D.A. Davidson & Co. in a update released Friday. Ramey has a "buy" rating on Usana's stock with a 12- to 18-month price target of $60.

Usana was raised to a "buy" from a "hold" by Wedbush Morgan Securities analyst Rommel Dionisio. And Jefferies & Co. analyst Douglas Lane reiterated his "buy" rating on the company's shares.

steve@sltrib.com