JP Morgan has forecast that Apple will ship more than 28 million iPhones in the final calendar quarter of the year, contributing to revenue of US$38.7 billion, reports Apple Insider.

Analyst Mark Moskowitz upped the investment bank’s projections from a previous forecast of 25.3 million units and total revenue of US$37.3 billion. In comparison, the final quarter of 2010 saw revenue hit US$26.7 billion, after 16.2 million iPhones and 7.3 million iPads were sold.

Moskowitz wrote in a research note that US operators have been surprised by the strong uptake of the iPhone 4S as well as the continuing popularity of the cheaper iPhone 4 and 3GS models. The older devices are expected to help Apple boost its presence in emerging markets, with China a particular target.

The previous best quarter for iPhone sales was the calendar second quarter of 2011 when 20.3 million devices were sold. The subsequent (calendar third) quarter saw a decline in sales as consumers waited for the arrival of the iPhone 4S. Apple CEO Tim Cook has said he believes the current quarter will set an “all-time high” for iPhone sales.

JP Morgan also raised its estimates for the next two fiscal years for Apple handset shipments with 105.5 million forecast for 2012 and 121.7 million in 2013. However, the investment bank lowered its iPad shipment estimate by 300,000 units to 13 million due to “limited uplift in build activity" and the expected impact of Amazon’s Kindle Fire tablet.