T-Mobile Sued Over Massive Data Breach Impacting 79 Million Americans

T-Mobile US, Inc. is facing a lawsuit from the Washington State Attorney General Bob Ferguson over a massive data breach that affected 79 million Americans. The lawsuit alleges that T-Mobile knew about cybersecurity vulnerabilities for years but failed to address them, leading to the 2021 data breach that exposed sensitive information, including names, addresses, and more.

The breach, which occurred in August 2021, compromised the personal information of approximately 76 million U.S. consumers. The specific information accessed for each person included some combination of names, addresses, zip codes, phone numbers, dates of birth, social security number/tax identification number, and/or other government identification number including driver’s license number, account establish date, name of authorized user, phone number, IMSI, MSISDN, PIN, and personal unlock code.

T-Mobile is accused of misleading customers about its security practices and notifying them in a timely manner about the breach. The lawsuit seeks restitution for Washingtonians harmed in the breach, along with injunctive relief to require improvements to T-Mobile's cybersecurity practices.



The lawsuit comes as T-Mobile continues to grapple with the fallout from the data breach. In 2022, T-Mobile agreed to pay $350 million to settle multiple class-action suits stemming from the data breach. Additionally, T-Mobile was fined $60 million by the Committee on Foreign Investment in the US (CFIUS) for failing to prevent or disclose unauthorized access to sensitive customer data.

While stock prices typically drop after a breach is disclosed, they tend to bounce back within a few weeks. However, the impact on stock performance can be muted in the long term. According to Comparitech's analysis, even though stock prices went back up after the initial breach disclosure, they were not as high as they would have been if the breach hadn't happened. Three years after the data breach, the stock price for the companies on average had risen 28.71 percent, but was down 15.58 percent compared to the NASDAQ index.

In T-Mobile's case, the company has already paid significant financial penalties due to the data breach, which could weigh on its stock price. Additionally, the ongoing legal battles and potential fines or penalties could lead to uncertainty among investors, potentially impacting T-Mobile's stock price.

The lawsuit against T-Mobile highlights the importance of robust cybersecurity measures for companies to protect customer data and mitigate potential financial losses. As data breaches continue to be a significant threat, companies must prioritize data security and be transparent with customers about any breaches that occur.