Stocks fell on Monday in shortened pre-holiday session, extending losses, on worries that President Barack Obama and congressional leaders will not be able to reach agreement to avert “fiscal cliff”. The non-partisan Congressional Budget Office forecasts the economy would go into a recession in the first half of 2013 if lawmakers are unable to strike a budget deal. Tech stocks joined a broad-market retreat, while Facebook bucked the bearish trend, gaining 2.55%, after Needham & Co. raised the target price to $33 from $25 and lifted 2013 earnings and revenue estimates. Implied volatility inched higher in very thin trading.