SO this is the thanks that Uncle Sam gets.

Six years after a forceful rescue of the financial system (and, derivatively, the economy) by two presidents and the Federal Reserve, a megarich individual and a battalion of investment funds are claiming unfair treatment and trying to extract billions in undeserved riches.

Call it by its proper name: extortion.

The weapon of choice is litigation — expensive, time-consuming court battles that have chewed through millions of dollars of taxpayer money in fees and countless hours of government officials’ time.

For the past few weeks, a trial has been underway in a Washington courtroom on one suit, the claim of Maurice R. Greenberg, the former chief executive of American International Group, that the harsh terms on which funds were provided to the company amounted to an unconstitutional taking of shareholders’ property.

His argument, simplified: The federal government saved other institutions on less onerous terms, so A.I.G. should have gotten one of those better deals.