Oracle Co-founder Larry Ellison is closing the gap with Tesla CEO Elon Musk as the world's richest person. This comes as Ellison's total fortune surged by $70 billion in a day, lifting it to $364 billion, according to Bloomberg Billionaires Index. With Oracle shares up 45% this year, Ellison now trails Musk, whose net worth is $384-billion, by $20 billion.