Billionaire businessman Warren Buffett joined the $100 billion club on Wednesday as investors drove the stock price of his company to a record high, according to the Bloomberg Billionaires <a href="https://www.bloomberg.com/billionaires/?sref=j3ErSqnQ">Index</a>. The 90-year-old chairman of Berkshire Hathaway is the sixth member of the elite club after his net worth surged to $100.4bn. Other members of the $100bn club include Amazon founder and chief executive Jeff Bezos, Tesla chief executive Elon Musk, Microsoft co-founder and philanthropist Bill Gates, LVMH Moet Hennessy's Bernard Arnault and his family and Facebook chief executive Mark Zuckerberg. Mr Buffett added $1.9bn to his fortune as Berkshire Class A shares hit a record high. Berkshire’s stock has surged higher in March, surpassing $400,000 on Wednesday. The firm’s A shares are up 16 per cent since the start of the year. In 2006, Mr Buffett started donating his company’s shares to the Bill and Melinda Gates Foundation and four family charities. He has given away more than $37bn in Berkshire Hathaway stock since then. “Without those gifts, which have cut his holdings of Berkshire Class A shares nearly in half, he’d be worth more than $192 billion,” Bloomberg said. Mr Buffett is also the co-founder of the Giving Pledge, a campaign to encourage billionaire philanthropy. Mr Bezos, the world's richest person with an estimated net worth of $180bn, was the first to hit <a href="https://www.thenationalnews.com/business/technology/jeff-bezos-fortune-tops-100bn-1.678647">$100bn</a> in 2017. Mr Buffett's company bought back a record <a href="https://www.thenationalnews.com/business/berkshire-hathaway-buys-back-a-record-24-7bn-of-own-stock-in-2020-1.1174120">$24.7bn </a>of its own stock last year and said there's more to come, as the conglomerate struggled to find other ways to deploy its enormous pile of cash.