Republican lawmakers are ramping up their investigation into billionaire George Soros’ acquisition of hundreds of U.S. radio stations, contending that this move could have major implications for media ownership and national security.

Soros, renowned for his substantial donations to Democratic and liberal causes, has become a target of scrutiny following the disclosure of his role in purchasing these stations just before the upcoming presidential election.

The controversy arises from the bankruptcy of Audacy Inc., the second-largest radio company in the United States. Earlier this year, Audacy filed for bankruptcy, enabling a Soros-backed fund to acquire a significant portion of the company’s debt. This deal ultimately granted the fund control over more than 200 radio stations. Republicans are particularly incensed by the Federal Communications Commission’s (FCC) decision to fast-track the purchase, which involved waiving regulations that typically restrict foreign ownership of media outlets.