U.S. realty trust giant Brandywine Realty Trust has confirmed a cyberattack that resulted in the theft of data from its network.

In a filing with regulators on Tuesday, the Philadelphia-based Brandywine described the cybersecurity incident as unauthorized access and the “deployment of encryption” on its internal corporate IT systems, consistent with a ransomware attack.

Brandywine said the cyberattack caused disruption to the company’s business applications that support its operations and corporate functions, including its financial reporting systems.

The company said it shut down some of its systems and believes it has contained the activity. The company confirmed that hackers took files from its systems, but it was still investigating whether any sensitive or personal information was taken.

Brandywine is one of the largest real estate trusts (REIT) in the United States, with a portfolio of about 70 properties across Austin, Philadelphia, and Washington DC as of its last earnings report in April.

Some of the company’s biggest tenants reportedly include IBM, Spark Therapeutics, and Comcast.

Since the introduction of new rules in December, U.S. publicly traded companies are obliged to disclose to investors cybersecurity events that may have a material impact on the business. As of the filing, Brandywine said it does not believe the incident is “reasonably likely to materially impact” its operations.