Five years after becoming the poster child for the Department of Justice’s war on banking secrecy and offshore accounts, Switzerland’s UBS AG finds itself in the eye of another potential tempest, this time the Puerto Rican bond crisis.

And to make matters worse, one of its top executives, Raoul Weil, was arrested in Italy last week. He is awaiting extradition to South Florida to face charges he assisted wealthy Americans hide assets from the Internal Revenue Service.