I think it's a question of liquidity. If most of his wealth is in equities, he can't just sell $40 billion of TSLA without causing a huge price drop and losing

I think it's a question of liquidity. If most of his wealth is in equities, he can't just sell $40 billion of TSLA without causing a huge price drop and losing voting power, etc. The way a lot of super wealthy people get liquidity is by getting loans against their less liquid assets. I think Elon did a combination of selling TSLA and getting loans to put together enough money to try to buy Twitter, IIRC.