Former Microsoft chief executive Steve Ballmer is now wealthier than Bill Gates.
Ballmer, who began his career at Microsoft as Gates' assistant, surpassed the Microsoft co-founder on the Bloomberg Billionaires Index on Monday for the first time.
According to the index, Ballmer is now the sixth-richest person in the world, with a net worth of $157.2 billion, topping Gates' $156.7 billion.
MELINDA FRENCH GATES DISHES MORE ON HER DIVORCE FROM BILL GATES
Bloomberg noted that Ballmer's wealth eclipsed Gates' as Microsoft shares hit a new record high on Monday. The stock is up more than 22% year-to-date, hovering around 455 per share on Tuesday.
The outlet said more than 90% of Ballmer's net worth is in Microsoft stock, and he is the company's largest shareholder. Gates, meanwhile, has diversified his portfolio and donated tens of billions of his personal wealth to philanthropic endeavors, including the Bill and Melinda Gates Foundation he founded with his ex-wife.
Gates also co-founded and signed the Giving Pledge, vowing to leave a majority of his fortune to charitable causes. Ballmer has not signed the pledge, but he and his wife launched their own philanthropic organization, the Ballmer Group, to improve economic opportunity for children and families in the U.S., and he has made several significant donations to universities.
BILL GATES MAKES CAMEO AT PARTY FOR MARK ZUCKERBERG'S 40TH BIRTHDAY
Ballmer spent over three decades at Microsoft, including nearly 14 years as the tech company’s CEO. He first became part of the company co-founded by Gates in 1980, when he took on the role of business manager, according to Microsoft.
GET FOX BUSINESS ON THE GO BY CLICKING HERE
Ballmer retired from the tech giant in 2014, before buying the Los Angeles Clippers NBA team. Microsoft’s current CEO, Satya Nadella, succeeded Ballmer in February of that year.
FOX Business' Aislinn Murphy contributed to this report.