US economy concerns knock shares

It's worst share losses in almost a year, after data showed that activity in the key US service sector unexpectedly shrunk in January.World stock markets renewed fears about the health of the US, the world's largest economy.Fears that the worst US housing slump in 25 years is crippling the wider economy sent the Dow Jones index down almost 3% and hit European shares.Economists had forecast a milder decrease to 53.0.The sell-off was broad based, hitting banking giants, technology firms and energy stocks.A reduction in their credit ranking would lead to banks, already reeling from losses centred on US mortgages taken out by individuals on low incomes or with poor credit, having to make further write-downs.