[dragonwriter]

> Can someone explain to me how the US has jurisdiction over Credit Suisse?

Because the US is a sovereign state, which means they have jurisdiction over whatever they choose to have jurisdiction over, subject to constraints forcibly imposed by outside parties.

> I see how they could have gone after the individual tax fraudsters (American citizens), but how can they police foreign banks?

The US government (even ignoring extraordinary action it could take outside of the US or with the cooperation of foreign governments) can effectively impose penalties on any entity that does business in the United States, or holds assets in the United States.

[cube13]

Or because they have branches and accounts in the US:

https://www.credit-suisse.com/us/en/

[aestra]

>impose penalties on any entity that does business in the United States, or holds assets in the United States.

Or even does business with US citizens.