U2 singer Bono, once described as "the worst investor in the US", is beginning to look rather shrew these days.

Last week it emerged that social media giant Facebook is limbering up to raise £6bn in a stockmarket flotation early next year. This sale of 10 per cent of the firm would value the company at an extraordinary £60bn.

Bono is one of the key players in California private equity group Elevation Partners, which has a 1.5 per cent stake in the social network.

Elevation spent £60m for 2.5 million shares in November 2009 and a further €89m for five million shares in June 2010. but since then, valuations of Facebook have exploded, with Elevation seeing its stake increase more than sevenfold in just over two years.

Facebook employs more than 300 staff at its Dublin base, many of whom may be in line for a major windfall when the company goes public next year.