London based equity firm 3G Group is said to be one interested party, according to reports.
News of the potential sale comes a week after Burger King reported a 2.3% drop in global sales during 2010 in financial results compared to a 1.2% rise in the same period in the previous year.
Its rival, McDonald’s reported better results with a 4.8% rise in sales during the second quarter of the year.
The chain has been a publicly owned company since 2006, but was previously owned by private equity.
Drinks maker Diageo, which owns the Smirnoff and Guinness brands, owned the burger chain until 2002 and still holds a 32% stake in the firm.
Burger King is the second largest global burger outlet following McDonald’s. It operates more than 12,000 outlets in 75 countries.
In May Burger King named ex-Coca-Cola marketer Natalia Franco as its chief marketing officer to replace Russ Klein who left Burger King in November.
Shortly after Franco’s appointment Burger King’s most senior European marketer David Kisilevsky left the fast food chain to join ad agency McCann Erickson.