This undated photo provided by the Howard G. Buffett Foundation shows philanthropist Howard Buffett, son of Warren Buffett, distributing aid in Posad-Pokrovske, Ukraine. (Spencer Taylor/Howard G. Buffett Foundation via AP)

FILE - Warren Buffett, Chairman and CEO of Berkshire Hathaway, left, plays bridge with Bill Gates, following the annual Berkshire Hathaway shareholders meeting on May 5, 2019 in Omaha, Neb. (AP Photo/Nati Harnik, File)

FILE - Warren Buffett, Chairman and CEO of Berkshire Hathaway, speaks to reporters before presiding over the annual shareholders meeting in Omaha, Neb., May 4, 2019. (AP Photo/Nati Harnik, File)

FILE - Howard Buffett receives presents during a visit with Colombia's President Ivan Duque, right, at a cocoa farm on Jan. 29, 2020 in La Gabarra, Colombia. (AP Photo/Ivan Valencia, File)