Belgian authorities have charged Swiss banking giant UBS with money laundering and serious and organized tax fraud.
The prosecutors said that the bank has been suspected of having directly approached Belgian customers, without going through its Belgian subsidiary, to encourage clients to set up structures aimed at evading taxes.
UBS in a statement said that it will continue to defend itself against any unfounded allegations.
"The Belgian authorities have confirmed today by way of a press release, that the investigating magistrate has opened a formal investigation against UBS AG," the bank added.
Belgian authorities said they were able to firm up the case against UBS through excellent cooperation from French authorities, who have conducted a similar inquiry into UBS’s activities.
The Swiss bank denied that its Belgian division, which has since been sold, had ever supported tax evasion.
In October 2014, UBS has paid EUR1.1bn ($1.4bn) security deposit for allegedly helping wealthy French clients evade taxes even as it continues to challenge the accusations.
In July 2014, Marcel Bruehwiler, chief executive of UBS Belgium unit, has been detained by local police on suspicion that he and the firm helped wealthy clients evade billions of euros in taxes.