Shares of T-Mobile (TMUS  ) took a sizable pre-market hit on Monday after news broke of a potential large-scale hacking resulted in the exposure of data belonging to 100 million users.

The first report of the potential breach came from Vice News' Motherboard , with reporters communicating with the alleged hackers through an online chat. In the exchange, the hackers told reporters that a fraction of data containing the information of 30 million users cost 6 bitcoin (equaling roughly $276,000, according to the BTC price at the time of writing). According to the seller, the data contained personal information such as addresses, phone numbers, social security and driver's license numbers. According to Motherboard reporters that saw a sample of the data, it appeared to contain accurate information.

T-Mobile, for the most part, has been quiet on the matter, telling multiple outlets "We are aware of claims made in an underground forum and have been actively investigating their validity. We do not have any additional information to share at this time."

While T-Mobile has yet to confirm the breach, nor has it disclosed the true scale of any potential breach, or when hackers had potentially gained access, its well known that the telecom giant has been an apparent favorite of hackers as of late. Within the last year alone, T-Mobile has been hacked two additional times, with confirmations in March and December of last year. According to statements made by T-Mobile at the time, the data of customers was exposed both times. The company had also reported breaches once in 2019, and once in 2018.

T-Mobile shares dropped 2.7% pre-market, completely reversing gains made over the last week. Investors seem to have remained spooked through the first half of the day, with shares sliding an additional 1% by noon on Monday.