Sensex tanked over 1,000 points to 73,608 on Friday, whereas Nifty lost around 250 points in mid-day trade, wiping out gains made in initial trading. Nifty had earlier touched an all-time high of 22,794.70 today. The indices fell due to a decline in index heavyweights Reliance Industries and HDFC Bank. Nearly all sectoral indices were also trading in the red.