I'm also 10% in small caps with a Russell 2000 index, but when a guy is paying out 0.75% annually to a fund that is going to underperform the market, I thought the important thing was to get him pointed in the right direction. He has 35 years to tweak it. Right now he just needs to stop giving his money away. That will make a much greater difference in his long term returns than the idea that an index 500 fund isn't diversified enough will. The stats have been run thousands of times since Bogle started pushing passive investments and they are pretty robust.

https://www.ft.com/content/4594f554-...b-4a9c83ffa852

And they've damn sure worked for me.