(Reuters) — The money laundering scandal at Danske Bank A/S deepened on Thursday when the Danish lender said it had received an inquiry from the U.S. Securities and Exchange Commission.

To bolster its defense, Danske, already under investigation in a number of countries, nominated former Dutch finance minister and ex-ABN Amro Bank NV CEO Gerrit Zalm to its board.

Danske is being investigated in Denmark, Estonia, France and Britain over €200 billion ($226 billion) in payments found to have flowed through its Estonian branch from Russia, former Soviet states and elsewhere.

The SEC is now also carrying out inquiries, adding to an ongoing criminal investigation by the U.S. Department of Justice in relation to the case of possible money laundering at Danske’s Estonia branch.

The value of Denmark’s largest bank has almost halved since last March, with investors concerned by the threat of hefty fines. The news about a new investigation by the SEC pushed its shares down a further 3.7% by 1215 GMT.

Shares in Swedbank AB have also tumbled over the past two sessions after Swedish television linked the bank to the Baltic money laundering accusations.

Danske will also propose Christian Sagild, former head of Danish insurance firm Topdanmark AS/ADR, to the board at its March 18 annual shareholder meeting.

Nominating Messrs. Zalm and Sagild to the board is the first concrete step by Karsten Dybvad, who took over as chairman in December.

Mr. Dybvad, former head of the main Danish business lobby group and a former government official, has been tasked with appointing a new permanent chief executive after Thomas Borgen resigned in September last year.

“We have no information about when the investigations conducted by DoJ and SEC are expected to be completed, nor do we know what the outcome of these will be,” said interim CEO Jesper Nielsen.

The new investigation came only two days after Estonia’s financial regulator took the unexpected step of demanding that Danske close its branch there and repay customers’ deposits within eight months, overturning the lender’s plan to scale back but keep business in the country.