Warren Buffett's company nearly quadrupled its investment in Apple to over 57 million shares during the last three months of last year.
Berkshire Hathaway Inc. filed a quarterly update on its U.S. stock portfolio with the Securities and Exchange Commission on Tuesday. Besides the Apple move, Berkshire also revealed a new stake in Monsanto.
Investors like to look at Berkshire's investments because of Buffett's remarkably successful track record although the filing doesn't make clear who made all the investments.
Buffett surprised many people last fall by disclosing new investments in American Airlines, Delta Air Lines, United Continental and Southwest. Berkshire added to the investments in American and United.
Besides investments the Omaha, Nebraska-based Berkshire owns more than 90 subsidiaries, including insurance, utility and jewelry firms.