The Indian rupee registered a massive fall of 67 paise and slipped below the 73 per US dollar mark in opening trade on Friday, tracking weak Asian currencies and heavy selling in the domestic equities.
At the interbank forex market, the domestic unit opened at 72.43 against the US dollar, then lost further ground and touched 73.10, registering a plunge of 67 paise over its previous close. On Thursday, the rupee had settled at 72.43 against the American currency.
Meanwhile, the dollar index, which gauges the greenback's strength against a basket of six currencies, advanced 0.25 per cent to 90.35.
"The Indian rupee started this Friday on a weak note against the US dollar, tracking the spike in the US 10-year yields, which lifted the dollar from three-year lows on Thursday," Reliance Securities said in a research note.
Most of the Asian currencies have started weak this Friday morning and could weigh on sentiments, the note added.
On the domestic equity market front, the 30-share BSE benchmark Sensex was trading 842.09 points lower at 50,197.22, and the broader NSE Nifty declined 217.35 points to 14,880.
Foreign institutional investors were net buyers in the capital market as they purchased shares worth Rs 188.08 crore on Thursday, according to exchange data.
Brent crude futures, the global oil benchmark, fell 0.39 per cent to $66.62 per barrel.