Iran's Central Bank is moving to bring part of its official foreign currency exchange rate into line with the much higher rate on the streets.
The bank announced Sunday that it would allow authorized money changers to trade dollars at 19,000 rials per dollar, while the official rate remains at 12,260.
The Iranian currency has lost much of its value because of Western sanctions over Iran's nuclear development program.
Iran has a burgeoning black market in currencies because of the wide gap between the official and street exchange rates.
It was not clear if the central bank would continue adjusting its market rate to reflect the unofficial street price.
The lower, official rate is still used for importing essential goods, in effect lowering their prices for Iranians.