Warren Buffett has said many times that being so large (and eg able to buy billion dolar companies) actually makes it more difficult for them to make money - be

Warren Buffett has said many times that being so large (and eg able to buy billion dolar companies) actually makes it more difficult for them to make money - because there aren't many companies large enough to make a difference, and everybody already knows about those companies. He's also been quoted as saying that if he only had a million dollars, he could double it in a year. I haven't seen him explain this specifically, but the idea seems to be to research companies that are not well known, because that's where you're more likely to find stocks that whose price are mis-valued. And this is the work side: you have to research all those stocks (not just the top 300 or so that have analysts following them), and you have to be sure (within a margin of safety) of your evaluation of their value (especially in terms of enduring competitive advantage). If they're selling cheap, with respect to your evaluation, you buy. It takes a lot of work, and self-confidence.