Commerzbank AG's Polish unit mBank SA asked some of its clients whose foreign exchange mortgage agreements were annulled by courts to pay for using its funds during the time when the loans were valid, Parkiet reported Nov. 18.

The lender claims that the right to demand clients to pay a fee on the use of funds granted under Swiss franc mortgage loans before their cancellation stems from a 2019 ruling of Poland's Supreme Court.

The Polish Office of Competition and Consumer Protection argues, however, that mBank's demands toward its clients have no legal basis under Polish and EU law. The watchdog asked the lender for explanations and does not rule out the possibility of launching proceedings against the financial institution.

In 2019, the European Court of Justice sided with Poland-based Swiss franc mortgage holders in their disputes with local banks. The ruling resulted in a surge of franc mortgage-related court cases, which prompted banks to boost their provisions on legal risks related to such disputes. MBank set aside 185.8 million zlotys in provisions in the third quarter against legal risk relating to its portfolio of Swiss franc-indexed mortgage loans.

As of Nov. 17, US$1 was equivalent to 3.79 Polish zlotys.