warren buffetts berkshire hathaway made a 500 million investment in the parent company of nubank a privately held digital bank based in brazil the south american company announced tuesday nubank which was founded in 2013 made its first appearance on cnbcs disruptor 50 list earlier this year the company said it has roughly 40 million customers the companys ceo told the wall street journal that an initial public offering is likely but is not planned buffett is no stranger to investing in financial firms as traditional banks and insurance companies make up a large portion of berkshires investment portfolio however buffett had sold nearly all of his stake in wells fargo by the end of the first quarter according to securities filings