Sensex, Nifty, Share Prices LIVE: Markets opened on a weak note on Friday, with the Sensex falling 393.63 points or 0.48 per cent to 82,172.74 and the Nifty declining 135.15 points or 0.53 per cent to 25,283.75 as of 10 AM, weighed down by sharp losses in metal stocks despite optimism ahead of the Union Budget presentation on Sunday.