The bourses remained under selling pressure on overnight key interest rate hike by RBI which overlapped the investors sentiment ahead of F&O expiry as the benchmark S&P CNX Nifty slipped further by 28.05 points at the National Stock Exchange (NSE). The trading commenced on a modestly positive note after yesterday's sell-off which attracted low level buying amidst a tinge short-covering pushing the key index to trade higher,though global cues were not supportive. Market could not sustain the momentum and turned choppy with profit-taking mainly in rate sensitive counters,particularly in banking,taking it into negative terrain. The sell-off got further aggravated after a sluggish European opening,taking the key-index to the day's lowest point. Some buying in blue chip counters and fmcg helped the market to cut short the losses. The dismal Q1 numbers from BHEL yesterday continue to put pressure on capital goods sectors amidst growth concerns over rate hike. "Furthermore unwinding of long positions by investors ahead of F&O expiry too added to the pressure on the market," traders said. The 50-share index swung wildly between a high of 5,591.70 and a low of 5,521.50 before concluding at 5,546.80,a loss of 28.05 or 0.50 per cent,over its last close. BHEL,PNB,JP Associates,Hindalco,Siemens,HCL Tech,Reliance Infra,Wipro,RPower and PowerGrid were the top losers from the Nifty. However,Maruti,Sesa Goa,DLF,Rcom,Bharati Airtel,HDFC,Ambuja Cement,HDFC Bank,Bajaj Auto and ACC managed to register some gains. Turnover in cash segment declined to Rs 12,639.43 crore from Rs 12,296.62 crore yesterday. A total of 5,960.21 lakh shares changed hands in 59,64,078 trades. The market capitalisation stood at Rs 65,84,477 crore.