Documents related to a Senate inquiry into Carrier IQ and its smartphone software reveal that Sprint is by far the company’s biggest carrier client in the United States. Sprint stated in a letter to Senator Al Franken, which is now public record, that Carrier IQ software is installed on more than 26 million of its handsets. A similar letter from AT&T states that the mobile tracking software is installed on 900,000 AT&T phones, but the carrier said it is only collecting data from approximately 575,000 of them. Both companies reaffirmed earlier statements claiming they only use Carrier IQ software for diagnostic purposes and not to gather private user data or to track subscribers. ”Sprint has not used Carrier IQ diagnostics to profile customer