Shares of fast food chain Burger King (BKC) climbed over 21% in premarket trading Thursday after already closing 14.65% higher Wednesday. The stock is getting a boost from rumors of a possible deal to sell the company.

CNBC reports, according to unidentified people it says are familiar with the situation, that 3G Capital is set to announce its acquisition of Burger King Thursday. The private equity firm, CNBC says, will take Burger King private for $24 a share or $4 billion.

A report Wednesday from The New York Times supports CNBC report regarding 3G capital, although it does not disclose a price.

Miami-based Burger King operates more than 12,150 restaurants in all 50 states and in 75 countries and U.S. territories worldwide. .