The BSE benchmark Sensex was down by 124 points to 16,909 in the late morning session due to selling from operators mainly in metal, refinery, banking and realty counters, triggered by fall in the overseas market. The 30-share barometer, which gained 326 points in last three sessions, fell by 129 points to 16,903 with in few minutes of trading.Similarly the NSE 50-share Nifty also declined by 42 points to 5,124.