Specific terms of the settlements were not disclosed, but AT&T said that all of the defendants have agreed to permanent injunctions that would prohibit them from conducting any future pretexting.
Pretexting involves a person fraudulently representing themselves as someone else in order to obtain personal details such as phone records.
The practice received widespread public attention last year when HP admitted that the technique had been at the centre of its boardroom scandal.
The AT&T suits related to an internal investigation which found that the records of 2,500 AT&T customers may have been compromised by investigators using pretexting tactics.
The suits were filed in a San Francisco district court on 23 August, when news of HP's wrongdoings was just beginning to emerge.
"We stated at the time we filed these suits that AT&T would use every means available to vigorously pursue individuals and companies who, through fraud, attempt to obtain unauthorised access to customer information," said AT &T chief privacy officer Dorothy Attwood.
"We believe that the results send a clear and decisive message that has had a significant and chilling effect on the pretexting community."
The settlement closes 15 of the 16 suits, leaving Lobel Financial Corp, a provider of car loans, as the sole defendant.
The State of California and the US Federal Government have passed laws in recent months strengthening the penalties for pretexting. The maximum jail term now stands at 10 years.
AT&T claims victory in pretexting suits
By Shaun Nichols on Apr 19, 2007 7:23AM