Twitter could face a $250 million FTC fine for using phone numbers to target ads - CNN

Twitter estimates the complaint could result in a loss of between $150 million and $250 million, it said.

The social media company admitted last October that it had "inadvertently" targeted ads at users through contact details that they provided for security purposes.

Twitter (TWTR) users are asked to provide information like their phone number to help secure their account through services such as two-factor authentication.

The FTC declined to comment.