updated 12:44 pm EST, Thu November 14, 2013
Devices were often unlocked for sale outside US
A change deterring mass unlocks of AT&T iPhones has effectively killed a portion of the iPhone resale industry, the Wall Street Journal reports. Until early October, businesses were able to buy large numbers of AT&T models and easily unlock them for sale in regions like China, where even an imported gray-market phone is often cheaper than what Apple and local carriers charge. Since the change has taken effect, though, some vendors that specialized in reselling unlocked iPhones have suffered or gone out of business.
Exactly what happened in October is unknown, but AT&T appears to have reversed course on its unlocking policies. Officially, the company has long insisted that it will only unlock devices on request for individual customers after their contract has expired. In practice, though, the per-device cost for firms unlocking AT&T iPhones has gone up from about $1-2 to as much as $100, indicating that AT&T has implemented new policies specifically targeted at resellers and unlocking specialists.
9to5Mac sources suggest that companies doing mass unlocks were previously mailing batches of IMEI numbers to AT&T. The carrier may now simply be refusing bulk requests, possibly on the basis that there's no way to verify if every unit is legitimate.
Clamping down on unlocking could be intended to keep more iPhones in the AT&T sphere. The company normally loses money on the iPhone hardware, due to subsidies paid to Apple; the profit comes from monthly voice and data fees. As a result, ensuring that everyone who wants to use an iPhone on AT&T can get one is critical.