The BSE gauge Sensex tumbled over 440 points and the NSE Nifty cracked below the psychological 15,000-level on Friday in line with relentless sell-offs in global equities as US bond market turmoil continued to rattle investors.

At the closing bell, the Sensex was quoted at 50,405.32, showing a decline of 440.76 points or 0.87 per cent over the previous close. Intra-day, the index swung around 726 points.

The NSE barometer Nifty ended lower by 142.65 points or 0.95 per cent at 14,938.10.

On the Sensex chart, IndusInd Bank, SBI, Dr Reddy's, NTPC, ICICI Bank, HCL Tech and Bajaj FinServ emerged as major laggards.

On the other hand, ONGC, Maruti, Kotak Bank, Nestle and Ultratech Cement were among gainers. Of the Sensex shares, 21 ended with losses.

Elsewhere in Asia, equity markets continued their decline on Friday after a retreat on Wall Street amid concerns that rising bond yields will lead to inflationary pressure.

"Domestic equities corrected for second consecutive day as rise in 10-Year USA Treasury yields and commentary from Federal Reserve chairman on rising bond yields weighed on investors' sentiments. Barring FMCG, all key sectoral indices witnessed sharp pullback with metals and PSU bank indices witnessing steeper correction in the range of 3-4 per cent, said Binod Modi, Head - Strategy at Reliance Securities.

Clearly, rising bond yield fear, which appeared to have softened last week, has come to the fore again with back-to-back sharp rise in USA treasury yields, he said, adding that a higher bond yield reduces future earnings or cash flow projections and therefore premium valuations of equities become doubtful.

Foreign investors had offloaded equities worth Rs 223.11 crore on a net basis in Indian capital markets on Thursday, according to exchange data.

On the forex market front, the rupee closed 19 paise lower at 73.02 against the US dollar. Global crude oil benchmark Brent was trading 1.26 per cent higher at USD 68.11 per barrel.