Billionaire businessman Warren Buffett toured a Mount Vernon business Thursday that he owns.

Buffett, who once lived in the area, acquired several jewelry companies last year. They then formed Richland Group, the largest jewelry manufacturer in the nation. The company is one of 76 that make up Berkshire Hathaway.

Buffett says the secret to his success is simple. "Berkshire has a policy that started in 1965 when I became involved to acquire perfect companies run by terrific people and that way I don't have to do anything," he says. "We trust our managers ? and we let them run their businesses."

Mount Vernon Mayor Clinton Young seized the opportunity, telling Buffett his investments in Mount Vernon are welcomed.

Buffett also shared his outlook on the economy as Young and Richland Group employees gathered around. "A lot of private equity companies talk about buying something with an exit strategy," he said. "Well, we have an entrance strategy, but no exit strategy. Our idea is to build and build and build."

Just one share of Berkshire Hathaway stock is worth close to $4,000.