Mumbai, Mar 20: The rupee depreciated further by 4 paise to hit its four-month low of 65.21 against the US dollar in opening session today on some dollar-buying by importers and banks and weakness in the domestic equity market.

The greenback's gains against major global currencies ahead of the US Federal Reserve's key policy meet that kicks off later in the day, in which it is expected to hike interest rates, weighed on the domestic unit, dealers said.

Yesterday, the rupee slipped 23 paise to close at 65.17 against the dollar due to concerns over a widening current account deficit. Meanwhile, the Sensex today fell further by 112.26 points, or 0.34 per cent, to 32,810.86 in early trade. FIIs bought shares worth Rs 292.23 crore on a net basis yesterday, provisional data showed.