European shares slipped after the Stoxx Europe 600 Index jumped the most in a period of 30 days as the U.S. economy is expected to boost and that may slow down the stimulus. The Stoxx 600 fell 1% to 305.06 as of 9:57 a.m. London time; the index is still set for 2.8% gain in May. The Stoxx 600 index has prolonged the win streak to 12 months and it has surged 9.1% in year 2013 to date.