Berkshire Hathaway ($BRK.A@US) CEO Warren Buffet initiated a position in the Brazilian Bitcoin-friendly bank Nu Holdings ($NU@Brazil) while dumping shares of Visa ($V@US) and Mastercard ($MA@US). Berkshire said in a filing with the U.S. Securities and Exchange Commission Monday that it purchased $1 billion worth of Nubank shares in the fourth quarter of 2021. It also sold $1.8 billion worth of Visa and $1.3 billion worth of Mastercard. On Tuesday, Nu Holdings shares spiked more than 5% in the regular session. In June, Berkshire invested $750 million in the digital bank. Nubank offers investment in Bitcoin through the QR Bitcoin ETF, a product of Easynvest, a company acquired by Nubank in the same month. In the past, Buffet has taken a public stance against Bitcoin. While Berkshire has not invested in cryptocurrencies directly, the companies that he did invest in have been gaining exposure to the world’s oldest cryptocurrency.