Bears, who were waiting for an opportunity, returned with a vengeance on Monday with the impending expiry of the derivative contracts and concern over slowdown in FII inflows in the last week of the calendar year, thereby casting a shadow over Dalal Street.The Bombay Stock Exchange Sensex witnessed its seventh biggest fall of the current calendar year 2005, shedding 171.02 points to end the day at 9,085.89 as 26 of the 30 Sensex stocks ended the day in the red. The broader S&P CNX Nifty of the NSE lost 59.2 points — the fifth biggest fall of CY05—to settle at 2,749.60. Incidentally, the fall was mostly due to domestic factors as most of the leading Asian indices ended Monday on a strong note. While Japan’s Nikkei gained 166 points on Monday, the benchmark indices of Taiwan, Thailand and South Korea also ended positive. “Lack of participation and profit-booking led to the fall on Monday. The nearing of the F&O expiry also played a role in the volatile session,” said Jay Prakash Sinha, associate VP, Kotak Securities.Incidentally, most market participants say the bourses are showing a bearish trend in the near-term due to the absence of any fresh triggers.Analysts are of the view that the Indian bourses fell as the expiry of the derivative contracts is nearing.