They have vaults from Switzerland to Hong Kong to Dubai, and they count among their clients some of the largest mining companies in the world. They know what they're doing.
And now they're dumping US citizens.
ViaMat does a great deal of business within the United States. As such, the company is heavily exposed to the insane US regulatory environment.
As an example, the 2010 Foreign Account Tax Compliance Act turned into more than 500 pages of regulation! The costs and risks associated with compliance simply became too much for ViaMat to bear.