According to a Bloomberg report, Sanford C. Bernstein research analyst Toni Sacconaghi said that up to a million of the 3.75 million iPhones sold last year have been unlocked, meaning that they’ve been hacked to run on wireless networks other than AT&T. The number is up from Sacconaghi’s previous estimate of 750,000.

In his research note, Sacconaghi estimates that Apple stands to lose a cool $300 million to $400 million for every one million unlocked iPhones.