Bloomberg Billionaire Index. Musk is worth $128 billion, with Bloomberg noted.
Last week, Musk snatched the No. 3 spot from CNBC reported Tuesday.
Tech billionaires make up seven of the Top 10 -- Google co-founders Larry Page and Sergey Brin are worth $81.3 billion and $78.7 billion respectively, while former Microsoft CEO Steve Ballmer has $76.1 billion.