iPhone 5 constraints remain at AT&T, Verizon, inventory improving at Sprint

Gene Munster and his team at Piper Jaffray polled 70 Apple Stores to check on availability of the iPhone 5. They found that supply is generally constrained for the more popular AT&T and Verizon models, though inventory is said to be improving for Sprint.

Piper Jaffray also conducted a poll this week of 738 U.S. customers which indicated demand for the iPhone 5 is increasing. A poll conducted prior to the iPhone 5 announcement found that 48 percent of customers who planned to buy a smartphone would choose Apple's next iPhone, while this week's poll found that 55 percent of those surveyed chose Apple's iPhone 5.

Increased demand in the iPhone 5 came at a cost to Android and Windows Phone. Among those surveyed, those who planned to buy an Android handset dropped from 39 percent to 35 percent, while Windows Phone fell from 9 percent to 5 percent.

"We believe the incremental strength in iPhone 5 demand following the product launch, despite the reported supply and Maps issues, suggests that demand for the phone remains strong," Munster wrote in a note to investors on Friday.

Apple sold 5 million iPhone 5 units over the device's launch weekend in late September. The company doesn't break down sales by model, but indicated in its quarterly report that it was seeing "phenomenal" demand for the handset that was outstripping supply. A total of 26.9 million iPhones were sold in the September quarter.