Swedish authorities searched the head office of Swedbank on Wednesday as part of an investigation into the bank's handling of money laundering allegations at its Baltic branches.
Adding to pressure on the lender, state broadcaster SVT said separately that Swedbank may have misled U.S. investigators over transactions by its customers linked to Mossack Fonseca, a Panamanian law firm at the center of a global tax avoidance and money laundering scandal.
The money laundering allegations have sparked fears that Swedbank, the largest lender in the Baltic region, will be swept up in a scandal that has already pummeled rival Danske Bank, with the threat of lawsuits, fines and other legal sanctions.
Swedbank said in an emailed response to Reuters following the broadcast that it "cooperates fully and communicates clearly, correctly and with the best intentions with all relevant authorities".
The Swedish lender has lost more than a fifth of its value since being linked with Danske Bank, whose Estonian branch was used for as much as 200 billion euros ($227 billion) of suspicious payments between 2007 and 2015.
Regulators in Sweden, Estonia, Latvia and Lithuania began a joint investigation into Swedbank after SVT in February reported allegations that at least 40 billion Swedish crowns ($4.3 billion) in suspicious transactions took place between Swedbank and Danske Bank's Baltic accounts over the same period.