75% VTI #core position. cap weighted total US market
10% AVLV #tilt large cap value
15% AVUV #tilt small cap value
No guarantees this outperforms 100% VTI, but it achieves the goal of softening the big tech concentration. 80% VEA #intl developed
20% VEXC #intl emerging, ex-China
Put it all together with a 60/40 US/intl split VTI 45
AVLV 6
AVUV 9
VEA 32
VEXC 8
The blow of a SpaceX pump-n-dump is a drop in the ocean on this portfolio. In addition, only free float SpaceX shares will be bought by the index which is a fraction of all of SpaceX. Even a more concentrated S&P500 portfolio would not get hurt too much by the pump and dump.
Replaced with a new set of problems of course. Like no money. And if the startup is successful it will eventually morph into a big fat corporate culture. The circle of life.