Apple may sell as many as ten million iPhone 5 units in the device's first week on sale.
That's according to an estimate from Piper Jaffray analyst Gene Munster, based on the widely tipped iPhone 5 release date of September 21.
"We believe that if the 21st is the actual ship date, Apple could sell six million to 10 million iPhone 5s in the final week of September barring supply issues," he said in a research note.
Munster went on to forecast iPhone 5 sales ranging between 26 million and 28 million units in 2012, AllThingsD reports.
Apple is widely expected to show off its new smartphone at an iPhone 5 reveal event this Wednesday, September 12.
Have a read of our iPhone 5 rumour round-up to get an idea of what Apple might be showing off later this week.