Does Discipline Still Matter? (Spoiler: YES!)
But here's what that dominance has done to the "market": the top five companies in the S&P 500 now represent 26% of its total value. The top ten account for nearly 36%. Think about that. When you buy an S&P 500 index fund believing you own "the market," you are placing an enormous concentrated bet on a handful of Silicon Valley giants. That's not diversification — that's a crowded trade with a diversification label slapped on it.