Baron's personal wealth soared as his fund made a successful bet on Tesla. Forbes estimates that his net worth has grown to $4.5 billion, nearly doubling from $2.3 billion in mid-March last year, largely because of the explosive 728% rise in Tesla's stock over the past 12 months. True to form, Mr. Baron, 78, remains upbeat about the market's outlook. "My faith is in the long term," he told Forbes.

While many investors are trying to predict the direction of the U.S. economy or interest rates, Mr. Baron doesn't worry about such things and sticks to his tried-and-true approach. His firm focuses on high-growth companies with long-term competitive advantages. "When we invested, our goal was to double our money every five years," Baron explains.