The Polish financial regulator said that Polish banks could collect up to 20.6 billion euros in provisions, which, according to the head of the financial organization, Jacek Jastrzybski, represents a “systemic risk” for the industry, with many creditors at risk of bankruptcy. Millennium Bank, the Polish branch of BCP Bank, announced this week that it has strengthened its provisions in the third quarter to deal with ongoing legal proceedings related to Swiss currency loans.

Successive EU rulings have undermined creditors’ valuations because rulings by Polish and EU courts favor mortgage holders. The ruling against the banks will allow customers to borrow interest-free loans.

“The European Court of Justice must realize the consequences of its decision on society,” Jastrzybski told reporters in Warsaw. “Adding a banking crisis to the economic slowdown would have a very negative impact,” he added.

Jastrzebski will attend this week’s hearing where his written opinion was rejected. The trial is expected to take place within 6 to 12 months and could affect around 400,000 Swiss franc clients, of whom more than 100,000 have sued their banks.