In his latest column for Forbes, top fund manager John Rogers looks at the notion of economic “moats”, and how investors can profit from companies that have them.

Rogers looks the wisdom of two great value investors — Warren Buffett and Charles Munger of Berkshire Hathaway — as it pertains to moats. Buffett, he says, has said of moats, “The key to investing is not assessing how much an industry is going to affect society, or how much it will grow, but rather determining the competitive advantage of any given company and, above all, the durability of that advantage. The products or services that have wide, sustainable moats around them are the ones that deliver rewards to investors.”

Munger, meanwhile, has said that superior companies have deep moats that are continuously widening. “In light of this we not only specify how wide a moat is but also how it is trending,” Rogers says of his own approach. “Is the moat stable, growing or shrinking? Sometimes it pays to own companies that everyone recognizes as wide-moated, while other times it’s a contrarian view on the moat that matters.”

Rogers offers three of his “moat” picks. Among them: spice giant McCormick & Co. “It has multiple customer bases and a strong moat for each of them,” he says. “No shopper, restaurant or potato chip company is likely to take the risk of trading down and serving food that doesn’t taste great.”