Breaking down last three-week winning streak, the 30-share index Sensex lost 403.41 points (2.19%) to mark its closure below 18k mark at 17,998.41.

In contrast, the broad-based Nifty index also declined by 121.95 points (2.20%) to end the day at 5408.70.

Stock markets across the globe were gripped under selling pressure on worries about the pace of the economic recovery in the US, the world's biggest economy.

The BSE Mid-Cap index dropped 186.49 points to end the week at 7,634.71, and the BSE Small-Cap index lost 234.81 points to close the week at 9,640.95.

The Sensex opened the week on a dull note with the gain of 7.53 points to 18,409.35 and the Nifty gained 12.85 points to 5,543.50.

On Tuesday and Wednesday, the 30-share index fell by 228 points and the Nifty declined by 81.15 points. Profit booking at upper levels together with worries of a slump in universal growth also affected the same.

The whole week saw huge volatility as dealers rolled positions in the derivatives section from the August 2010 series to September 2010 series.

The trading on Thursday saw huge volatility on account of bargain hunting after a two-day fall.

On Thursday, Prakash Steelage made its debut at Rs 118.55, a 7.7% premium over the IPO rate and closed the session at Rs 187.95 on the Bombay Stock Exchange (BSE) at a premium of 70.8% over the IPO cost of Rs 110.

On Friday, the 30-share index slipped 227.94 points to end below 18K at 17,998.41 and recorded a 30-day's low due to huge selling activity in real estate, bank and IT scrips considering pessimistic worldwide signals.

Likewise, the Nifty lost 69.20 points to end the week at 5,408.70 as capitalists fretted over the speed of the economic revival in the United States.

The major losers during the week were JP Associates, which lost 9.21% to end the week at Rs 111.90, accompanied by Rel Infra slipped 8.19% to mark its closure at Rs 982.

Other top losers of the week comprised Hindalco Ind that plummeted 8.09% to end at Rs 163.55, DLF fell by 7.54%, Hero Honda down 6.86% and Sterlite Ind dropped 4.91%.

In contrast, the top gainers during the week included ONGC, which advanced 4.73% to Rs 1317.65, Bharti Airtel gained 1.95% to Rs 316.20, NTPC zoomed 1.40% to Rs 195.95, ACC climbed 0.17%, Jindal Steel and Power surged 0.11% and Bhel grew by 0.03%.