Piper Jaffray analyst Gene Munster believes Apple is taking $18 per month for each iPhone subscriber under its deal with AT&T.

Apple has confirmed it has reached a revenue deal with AT&T, but has never revealed what it is. Munster - who once thought Apple was receiving $3 per subscriber has changed his mind based on information gleaned from Apple's most recent financial report.

Apple's accounts describe $118m in iPhone and iPhone-related revenue during the quarter. Apple has previously confirmed plans to account for iPhone (and Apple TV) sales across a two-year period.

Munster took the 1.4 million iPhones Apple's sold so far, took away the 250,000 units Apple said it believes were bought to unlock from AT&T's network, and calculates that 1.15 million revenue-generating iPhones contributed to Apple's quarter.

If Munster's estimates are correct, AT&T will pay Apple $432 per iPhone subscriber across the two-year life of the contract.