By Andy Bruce LONDON (Reuters) - Chinese factory activity shrank in May for the first time in seven months, overshadowing signs that the euro zone's downturn tempered slightly in May, business surveys showed on Thursday. World stock markets tumbled after the Chinese data and also in response to U.S. Federal Reserve Chairman Ben Bernanke, who hinted on Wednesday the Fed could soon pare back its bond-buying with new money if the economy maintains momentum. China's flash HSBC Purchasing Managers' Index (PMI) entrenched fears recovery in the world's No. ...

By Chuck Mikolajczak NEW YORK (Reuters) - Stock index futures fell on Thursday, putting the S&P 500 on track for its first daily back-to-back declines in a month, amid investor concerns the U.S. Federal Reserve may begin to taper its stimulus measures and over weak data in China. The S&P 500 posted its biggest decline in three weeks on Wednesday, after minutes from the latest U.S. Federal Reserve meeting showed some officials were open to tapering large-scale asset purchases as early as at the June meeting. ...