malefactor of great wealth: monopoly, large corporation, or rich individual who makes money by unethical means
Theodore Roosevelt popularized this term, using it on a number of occasions, both before and during his presidency. For example, it appears in an essay written in 1909 for The Outlook titled "The Thraldom of Names:" "The big newspaper, owned or controlled in Wall Street, . . . which is quite willing to hound politicians for their misdeeds, but which with raving fury defends all the malefactors of great wealth . . ."
Roosevelt was deeply opposed to monopolies, which were more commonly known as trusts during the early twentieth century. His strenous efforts to break up large monopolies and regulate corporate activities earned him the nickname "Trust buster."
Malefactors of great wealth has become a popular phrase once again, thanks to recent Wall St. hijinks. It appeared in newspaper articles and op-ed pieces dozens of times in 2009, as in this sentence from Bob Herbert's New York Times column of July 13, 2009: "These malefactors of great wealth (thank you, Teddy) developed hideously destructive credit policies and took insane risks that hurt millions of American families and nearly wrecked the economy."