Warren Buffett lamented a rare year of under-par investment performance in his annual letter to Berkshire Hathaway shareholders, and said he and vice-chairman Charlie Munger were on the lookout for big companies to add to their sprawling conglomerate.

The investors last month sealed a deal to invest $12 billion in the $28 billion buyout of ketchup maker Heinz, with private equity group 3G Capital, but Mr Buffett said he was on the prowl for another big deal. He said Berkshire invested $12.1 billion last year in capital spending and 26 small deals to add units or businesses to existing Berkshire subsidiaries, soaking up most of the group's earnings, but that "Charlie and I have again donned our safari outfits and resumed our search for elephants".

Mr Buffett, known as the "Sage of Omaha" for his unparalleled investment record over almost five decades, also criticised fellow chief executives for their unwillingness to invest. Last year was one of only nine years in which the book value per share in Berkshire Hathaway failed to beat the performance of the S&P 500 - the metric by which Mr Buffett judges his performance.

- (Copyright The Financial Times Limited 2013)