The punishment for financial crime should be the surrendering of your entire net worth, right down to the bone, with a 10% "finder's fee" allocated to the auditor (or whoever) that discovers the fraud (or whatever). The beautiful part is that this becomes a self-policing system. If you, as an investigator, are tempted to look the other way for a bribe, you become the very type of person the other regulators are chasing, and you risk your entire fortune as a result. If you manage to hide your assets under some other person's name, you make them an accomplice and they forfeit everything, too.
It doesn't even have to act as a deterrent, because you'd be systematically stripping the corrupt of their hard-stolen cash and at the very least forcing them to start over while the government finally gets all the taxes they've dodged over the years and then some. Everyone wins except the people who defrauded the system. And their dependents, actually, I suppose. Still, with the government suddenly coming into these huge piles of cash, there should be plenty to allocate to welfare systems.
Mokalus of Borg
PS - It might be hard to get at the cash if it's in offshore banks.
PPS - And this might be kind of extreme, but we're in extreme wealth disparity right now.