Warren Buffett’s fortune reached $100 billion on Wednesday, as investors drove the stock price for his company Berkshire Hathaway to a record level. Buffett’s net worth, as measured by Forbes magazine, comes almost entirely from owning about one-sixth of Berkshire, a roughly $600 billion company. Berkshire’s stock price has surged higher in March, with its Class A shares surpassing $400,000 on Wednesday. That came after the Omaha, Nebraska-based company on Feb. 27 said fourth-quarter operating results improved despite the coronavirus pandemic, while gains in Apple and other stocks fueled a $35.8 billion overall profit. The 90-year-old Buffett’s net worth would be higher had he not in 2006 begun donating his Berkshire shares to the Bill & Melinda Gates Foundation and four family charities. Buffett had previously owned nearly one-third of Berkshire, and his donations have totaled more than $37 billion when they were made. Berkshire was a failing textile company …