1. Libor scandal: For years, some of the world's biggest banks have manipulated an interest rate that affects borrowing costs for just about everybody. The scandal could cost the banks $35 billion in fines and legal costs, according to one estimate, and Libor manipulation probably cost taxpayers, borrowers and investors more than that.
2. Enron: This horrible, horrible company is special not only for its spectacular accounting fraud, but also because it managed to further screw the public by manipulating California's energy market. The Enron scandal led to Sarbanes-Oxley and the death of accounting firm Arthur Andersen.
3. Bernie Madoff Ponzi Scheme: In the biggest individual act of financial fraud in U.S. history, Bernie cost his victims about $18 billion. Not bad.
4. Subprime CDOs: Investment banks took junk mortgages that were hand-picked by hedge funds betting against them, crammed them into bundles and sold them to gullible investors, helping set the stage for the financial crisis of 2008.
5. Charles Ponzi, the O.G. Ponzi schemer: The Italian immigrant fleeced his victims for about $20 million in 1920, or about $229 million in 2012 money. That's not the most expensive fraud of all time, but the fact that people forever after named this kind of scheme for him puts him in the running.
6. Nick Leeson Rogue Trades: This is almost more an example of a trade gone horribly wrong (the subject of a future death match), but this trader committed fraud in hiding
