Musk's net worth fell below $400 billion for the first time this year on Monday, according to Bloomberg Billionaires Index.

Here's a list of the top ten richest people in the world, nine of which are American billionaires. See Elon Musk's net worth.

Trump has threatened to place a 25 percent tariff on imports from Canada and Mexico, as well as a 10 percent additional ...

It's well documented that Musk's maternal grandfather was involved in controversial movements and political parties.