AT&T and Verizon versions of the phone are especially hard hit, at least according to a survey taken by Gene Munster and team at Piper Jaffray, a banking and asset management firm.
Piper Jaffray polled 70 Apple Stores about the "Five's" availability, finding that the more popular AT&T and Verizon flavors have a "generally constrained" supply.
Inventory for Sprint's version of the phone is said to be improving. Sprint stores on the East Coast reportedly ran low or out of the iPhone 5 when the phone launched Sept. 21.
Grow it shall
Piper Jaffray also asked 738 U.S. customers about the iPhone 5 and their next phone purchases preferences, concluding that demand for the iPhone 5 is on the rise.
The firm's polling found 55 percent of respondents would choose the iPhone 5 for their next smartphone, up from the 48 percent who said they would in a poll taken before the phone's announcement.
Though a relatively small survey sample, Piper Jaffray's data supports the likelihood that the iPhone 5 will be one of Apple's best selling products, to the detriment of other manufacturers.
"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," Gene Munster wrote in an investor note Friday.
During an earnings call last week, Apple CFO Peter Oppenheimer reported that iPhone 5 demand continues to outstrip supply, and the company is taking measures to fill orders.
The second figure only includes nine days of iPhone 5 sales.
TechRadar has reached out to AT&T, Verizon and Apple and will update this story if and when the companies respond.