Warren Buffett becomes joint largest IBM investor

Warren Buffett has bought a 5.5 per cent stake in IBM, in a break from the veteran US investor's policy of avoiding the technology market.

In an interview on television station CNBC, the outspoken Buffett said his Berkshire Hathaway company had begun purchasing IBM shares in March, and his holding now stood at around 64 million shares - a 5.5 per cent stake, worth $10.7 billion.

According to data from Thomson Reuters, the holding makes Buffett the joint largest investor in the technology firm, along with State Street Global Advisors.

Buffett said this was the first time he had spoken publicly about the investment, that IBM was unaware that he had built up the stake.

Buffett has been traditionally wary of investing in the technology sector, issuing a warning earlier this year of what he feared would be a new Dotcom bubble caused by "overpriced" social network valuations

Explaining his shift in thinking, Buffett said that every year, he read IBM's annual report - his preferred method of identifying companies to invest in - but that this year he had "read it through a different lens."

Since Buffett began investing in the company in March, IBM's share price has risen around 17 per cent.