The new price took effect Sunday, The Wall Street Journal reports. Nokia's and AT&T's website have both been updated to reflect the change.
The price cut comes less than a month after Microsoft unveiled its next-generation mobile OS, Windows 8 -- and with it, news that Lumia 900 phones will not be getting the upgrade. If the phone wasn't selling well before that bit of news dropped, it's likely selling much worse now.
A Nokia spokesperson told the Journal that the move was "a normal strategy that is put in place during the life cycle of most phones." He pointed out Samsung's Galaxy S II experienced a similar price drop in that timeframe.
Sales of the Lumia 900 initially appeared to be strong; the device was listed as the bestselling smartphone on Amazon the week following its release. Reviews were overwhelmingly positive.
The Finnish company has had a tough quarter. Last month, Nokia announced it will close its factories in Finland, Germany and Canada, and lay off up to 10,000 workers before the end of 2013. The company reports second-quarter earnings on Thursday.