By Dan Weil The research firm came up with a list of the best companies to own based on ones to which Morningstar analysts assign a wide moat. With the S&P 500 dropping 25% year to date, you may be looking for buying opportunities in the stock market. Morningstar came up with a list of the “best companies to own.” The companies are ones to which Morningstar analysts assign a wide moat. That means the analysts think they have competitive advantages that will help them produce returns that outweigh their costs for the next 20 years. The companies have predictable cash flows and make smart decisi…