Overvalued stocks. Tesla stock has no business being vakued at what it is. Elon's wealth is all based on imaginary money until he cashes out. Unfortunately, he can borrow against those stocks while still owning them so it does give him some liquidity.
By the way, that's why the rich really want low interest rates: so the loans they take out against their stocks have a low rate. If that rate is lower than what their stocks pay out they have a magical cash machine. And tha's why we need to fix capital gains taxes; if you can borrow against stocks then that should be considered profiting from them and taxed accordingly.
Oh, and capital gains taxes, along with corporate taxes, should far exceed income taxes from labor, but I've digressed far enough.

Kirk Cameron would like a word you about his more recent works...