If bitcoin were an equity, then the U.S. Securities and Exchange Commission might be looking at it.
But even if they did ... if you are in Brazil, Russia, India, China, or wherever, ... how would what the SEC does be relevant? (yes, I'm being purposely obtuse, but remember that bitcoin is data, and as such it knows no borders.)
And remember certain US agencies have huge power outside the US. The DEA and the IRS come to mind.
I don't know which US agency will flip out when bitcoin becomes popular, but I'm quite certain one of them will, once it becomes widespread to exchange for illegal items, and used for money laundering.
It's also widespread enough to use instead of a Swiss bank account to hide money. Just move the money into a Bitcoin wallet, encrypt the wallet, and store copies of it on as many computers, in as many countries as possible.