After a smart rally in the first two weeks of the new year, the stock markets came under a bear grip during the week ended January 18 and clocked its biggest weekly loss due to various negative cues.The main index of the Bombay Stock Exchange (BSE), the Sensex, plunged 1,813.75 points (8.71%) to close at 19,013.70 when compared with the last weekend close of 20,827.45.The S&P CNX Nifty of the National Stock Exchange (NSE) tumbled 494.80 points (7.98%) to end the week at 5,705.30 as against the previous weekend close of 6,200.10.According to technical analysts, panic selling was sparked off when a technical level (Sensex support of 19,337) was broken on Friday, and the Sensex logged its fourth biggest fall of 687 points.Another factor was the sudden selling onslaught by hedge funds, which booked profits to cover up their mortgage-related losses in the US markets.Foreign institutional investors (FIIs), which are supposed to allocate funds for the new calendar year, pulled out over Rs 6,200 crore (including the provisional numbers for Friday) during the week.Global factors, too, weighed on the market. All emerging markets witnessed heavy selloffs triggered by fears about a likely recession in the US.Nearly Rs 5 trilion market capitalisation was wiped out in the five-day bear phase.