There are two true answers here. 1. Very large investors actually don't do anything different. The best game in town is the efficient frontier (modern portfol

There are two true answers here. 1. Very large investors actually don't do anything different. The best game in town is the efficient frontier (modern portfolio theory; essentially, spread the bets around so some zig while others zag). Once you have more than $10 M or so, it becomes worthwhile to start optimizing at the margins; there are things that can be done with tax efficiency that have tiny but real gains, and there are things like exploiting the short rebate and negotiating for special concessions. But as a passive, financially-oriented investor, you're basically playing the diversification game. 2. That said, very large investors almost all get to be that way not by the diversification game, but by the concentration game. Think about the wealth generation period of any industrial fortune: it comes from highly concentrated equity holdings in a corporation undergoing a massive change in valuation (archetypally, profitable growth, although many an investor has done well by changing the valuation through other means, see ESL and K-Mart). So. The way a person gets super rich is by doing something very different than what you are (should be) doing. And so while they are in that period, their portfolio looks very different. But once they are super rich, if they go to the world's best advisors, they are likely going to get something that looks like a well-diversified asset allocation according to modern portfolio theory.