LONDON Oct 23 (Reuters) - European shares broke their nine-day winning streak on Wednesday as blue chips including chip maker STMicroelectronics and brewer Heineken unveiled weak updates and traders took profit on "overbought" indexes.
Heineken cut its full-year profit guidance due to a drop in sales in some regions while quarterly revenues at STM fell short of analysts' expectations, sending the stocks down 3.1 percent and 5.7 percent, respectively.
Finnish utility Fortum, fell 5.8 percent, after it reported a weaker-than-expected underlying third-quarter profit, which it blamed on low hydro power production.
The euro zone Euro STOXX 50 index fell 0.5 percent to 3,030.24 points, with the pan-European FTSEurofirst 300 also down 0.5 percent at 1,281.44, retreating from a five year-high.
The euro zone Euro STOXX 50 index was at its most "overbought" since 2006 on Tuesday, when its 14-day Relative Strength Index, a measure of buying momentum, hit 73 points.
A reading above 70 indicates "overbought" conditions. The Euro STOXX 50 has fallen each time its RSI came close to 73 over the past seven years. Germany's Dax was also in "overbought" territory by the same indicator.