But 90% seems to me too much.
We don't know the future and bitcoin has a lot of mighty ennemies (states, central banks, politicians, etc...).
Imagine what you will do if all of a sudden 1BTC= 0$
I view 75% as a maximum.
Personnality I am more carefull and stay around 50%, with gold, real estate and cash for other 50%.
well, yeah. that would be even better, but unless there's a legal way to roll my capital gains into another asset, I'd have to pay a huge tax penalty. and it's hard to imagine a scenario that would cause a crash to zero barring a new tech that cracks the encryption. the closer BTC comes to zero, the more attractive it is to guys like me who want to buy low.
If you think there is a tech coming that will break the encryption then I've no idea what you are investing in bitcoins for ....