The problem is that you have to know how often they get caught in order to decide the amount. For example, if they only get caught 1/4 of the time, the fine nee

The problem is that you have to know how often they get caught in order to decide the amount. For example, if they only get caught 1/4 of the time, the fine needs to be greater than four times the amount stolen to make a difference (force the expected value of the behavior below zero). In practice, it would probably need to be quite a bit higher than that since people who do this sort of thing are likely risk-takers/gamblers. So there are then two things you have to guess at. First, how often they get caught (which is difficult, but not impossible to estimate) and second, how far below zero the expected financial payoff must be to change the behavior. You also have to figure out what happens when they don't have the money (or the money is well-hidden). Do they just go into some kind of negotiated payment schedule like people who lose lawsuits? That might have no impact at all since their illegal earnings are likely to be hidden from authorities anyway (or can be if needed). This is why I favor prison, because a prison sentence is much harder to "cheat" or nullify. No one lives forever, so prison is like taking a small chunk of a precious commodity away from someone. Additionally, if you are a big earner, prison is actually worse for you in some ways because you generally lose your income while incarcerated. This means that even very rich people or people who hide their wealth from the authorities can be punished effectively with prison time.