The U.S. Department of Justice (DOJ) sent Volkswagen a subpoena under the Financial Institutions Reform, Recovery and Enforcement Act of 1989.
The automaker faces investigations across the globe after the company admitted, in September 2015, to installing an emissions cheat system in approximately 11 million vehicles, according to a report by Reuters.
A federal judge also imposed a March 24 deadline for Volkswagen to state whether it has found an emissions fix for 600,000 U.S. diesel vehicles that is compliant with the demands of U.S. regulators.
Prior to that, the department sued Volkswagen for up to $46 billion for violating U.S. environmental laws. VW and its Audi and Porsche brands are barred from selling any new 2016 diesel models in the U.S.
The automaker faces more than 500 lawsuits from U.S. vehicle owners.