Warren Buffett"s Berkshire Hathaway Inc(BRKa.N) invested $500 million in Brazil"s Nubank, giving the fast-growing fintech a big vote of confidence as it seeks to widen its footprint across Latin America. Nubank, best known as a credit card issuer, also said it raised an additional $250 million from a series of other investors. The new investments give Nubank a $30 billion valuation, up from $25 billion at the time of its previous fundraising round, according to a source familiar with the situation. That would make the upstart bank worth just slightly less than Banco Santander Brasil SA (SANB3.SA), Brazil"s No. 3 bank, which has more than 2,000 branches. The transaction also vaults Nubank into the upper echelons of fintechs worldwide, on a par with brokerage startup Robinhood Markets Inc and China"s Lufax but still far behind Ant Group. Nubank, which has 40 million clients, said in a statement it plans to use the proceeds to fund its international expansion to Mexico and Colombia, launch new products and services and hire more employees. The arrival of such high-profile investors, who usually invest in publicly traded companies, gives a hint on how close Nubank is to a listing. Earlier in April, Reuters reported that Nubank had initiated preparations for a U.S. stock market listing which could come as early as this year, according to sources familiar with the matter. read more BERKSHIRE BETS IN BRAZIL Nubank is Warren Buffett"s second bet on a Brazilian financial startup. His Berkshire Hathaway also acquired a stake in payments company StoneCo Ltd (STNE.O) almost three years ago, when it went public. A highly concentrated financial market, in which the five top lenders hold almost 78% of the country"s total assets, Brazil has been a hotbed for fintech growth. Online banking has reduced costs for newcomers and the central bank has created new rules to encourage competition, aiming at lower fees and interest rates for consumers. Nubank"s $750 million new funding round is part of its series G fundraising round, which totaled $1.15 billion. An initial part of the series G round was announced in January. Other participants in the round included Sands Capital, Canada Pension Plan Investment Board, MSA Capital, Advent"s Sunley House Capital and Brazilian asset managers Verde Asset Management and Absoluto Partners.