[cletus]

That really doesn't change anything. If you want to do business in the US (and everyone does) then you're subject to US laws. "Jurisdiction" here is simply a question of how a country defines it and is willing and able to prosecute it.

For example, if two US citizens on US soil discuss insider trading of an Australian company that does not even do business in the US using trades on US brokers, those two individuals are in violation of the Australian Corporations Act and can be criminally prosecuted (by Australian authorities). Why? Because Australia claims jurisdiction over any Australian company.

Likewise, "sex tourism" with children in South East Asia is rampant and many countries are unwilling or unable to prosecute. Australia has deemed having sex with an underage person in a foreign country is likewise a crime in Australia that they can and do prosecute.

The US is able to to exercise a lot of power with international banks because they have the power to remove a financial institution's access to the US banking system. It's this stick that allowed the IRS to go after Swiss banks for complicity in US citizens evading US taxes.