Warren Buffett, the man often described as the world's best investor, appears to have abandoned his long-held contempt for overvalued technology shares by buying a stake in Microsoft.
The latest move by Mr Buffett's company, Berkshire Hathaway, follows his repeated warnings that technology shares were overvalued and that he did not understand them. It also comes after a patch of poor performance by the firm.
Mr Buffett had wanted to keep the purchase of 167,500 Microsoft shares a secret for up to a year but the US securities and exchange commission rejected the request for secrecy and Berkshire reported its purchase late on Tuesday.
Some analysts suggested that the tentative purchase, worth about $167m (£104m) at the end of September, could reflect Mr Buffett's personal relationship with Microsoft's co-founder Bill Gates as much as a conversion to the world of technology. Mr Buffett has been described as a mentor and good friend of Mr Gates and the pair are known to play online bridge together.
A Berkshire official refused to discuss the purchase yesterday. Previously, the company has bought a stake in First Data Corporation, which processes payments for e-commerce companies.
The surprise in the Microsoft stake is that Berkshire typically buys stakes in undervalued groups and holds them for a long period of time.
Berkshire has attracted an almost cult-like following with its adherence to stocks Mr Buffett can understand. However, many of these stocks, including companies such as Coca-Cola and Gillette, have underperformed the market in the past year as technology shares have raced ahead.
Shares in Berkshire fell almost 4% on Tuesday before rebounding slightly yesterday morning. The company, which has enjoyed compound annual returns of about 25% in the past 35 years, has seen its premium rating fall in the past year.
The company has publicly denied that the 69-year-old Mr Buffett wants to retire. Under SEC rules, investment funds with more than $100m in assets under management have 45 days from the end of each quarter to disclose changes to the firm's holdings.
