(Reuters) – Facebook Inc. said it is investigating whether a security breach it disclosed last week affected users of its enterprise chat app, Workplace. The company’s shares fell 2 percent to $159.26. The social media giant said hackers stole digital login codes that could have allowed them to take over nearly 50 million user accounts. However, the company said it had not yet determined whether the attackers misused any accounts or stole private information. A Workplace spokesman said on Tuesday there was currently no evidence to suggest any of its customers were affected. “We are investigating and are reaching out to customers directly to update them,” the spokesman said. Business Insider was first to report the potential issue with the app. (Reporting by Sonam Rai in Bengaluru; Editing by Shounak Dasgupta)