If I recall correctly, CitiBank merged with Travelers Insurance, Primerica and SmithBarney illegally in 1998 to create Citigroup. This was, at the time, completely illegal and in violation of the Glass-Steagall Act. The Glass-Steagall Act was enacted during the Great Depression because of exactly the mess we're facing now: banks insuring each others' debts with money they don't actually have in cash and cooking up crazy swaps and tranches and hallucinatory money that does not actually exist. CitiGroup lobbied Congresscritters and managed to get the Glass-Steagall Act repealed (this was a bipartisan effort--both Donkeys and Elephants agreed) two years later.
I'd say that since this was clearly their doing, and since they were in fact doing illegal crimes for two years, we should throw them in jail and seize the CEOs' private assets for the government. After all, if we can seize the assets of drug dealers, we can seize the assets of the buggers who are wrecking the economy. No cushy country-club federal pen, either, I want to see those guys in the county pen where Rocky tells John Reed that he sure does have a purty mouth...