Warren Buffett talks about this in stock investing: you're more likely to find a bargain in the under-researched companies, because there's greater variance bet

Warren Buffett talks about this in stock investing: you're more likely to find a bargain in the under-researched companies, because there's greater variance between the stock price and the stock value (price inefficiencies). He's publicly claimed to be able to double a million dollars in a year with this approach (it won't work for his $40+ billion, because there aren't enough under-researched stocks to buy that are also bargains).