AMZN was $1,010 on 2017-Jul-17. Right now it's $1,813. That's a ~80% increase, so it's extremely plausible that his net worth went up by 50% (in fact, I'm surpr

AMZN was $1,010 on 2017-Jul-17. Right now it's $1,813. That's a ~80% increase, so it's extremely plausible that his net worth went up by 50% (in fact, I'm surprised it didn't go up by more).