In most countries jails are no good to prisoners. They are used to isolate people from society, not to help people to become a better person. And society is putting tones of money to support penitentiary system.
I believe for economical crimes people who took the decision should be fined a lot and banned from taking positions where they can do the same things again. No need to isolate them from society. At least for the first time. The same for other crimes where people do not hurt or threaten to hurt other people.