Their firms do more business in some corners of the financial world than many banks, including lending to low-income homeowners and small businesses. They lobby members of Congress. And they have put large sums of money behind presidential candidates, at times pumping tens of millions of dollars into super PACs.
The hedge fund industry has now ballooned in size, to $2.9 trillion, from $539 billion in 2001. So, too, has the pay of the industry's leaders.
When Institutional Investor first started ranking hedge fund pay 15 years ago, George Soros topped the Alpha list, earning $700 million. In 2015, Mr. Griffin, who started trading as a Harvard sophomore out of his dorm room, and James H. Simons, a former math professor, each took home $1.7 billion, according to Alpha magazine. The two topped the list last year, too.
Mr. Griffin's firm, Citadel, has grown from a hedge fund that managed family and pension fund money into a $25 billion firm that has expanded into the securities business, taking business away from the brokerage units of banks like Morgan Stanley and Goldman Sachs. Along the way, his own personal wealth has grown exponentially, and is estimated by Forbes at $7.5 billion.
He recently made headlines when he paid $500 million for two pieces of art. In September, Mr. Griffin, 47, reportedly paid $200 million to buy several floors in a new luxury condo tower that is being built at 220 Central Park South, in Manhattan.
Yet it is arguably on the national and political scene where his money has had the most impact. He was the biggest donor to the successful re-election campaign of Mayor Rahm Emanuel of Chicago. More recently he has poured more than $3.1 million into the failed presidential campaigns of Marco Rubio, Jeb Bush and Scott Walker, as well as the Republican National Committee.
Citadel's flagship Kensington and Wellington hedge funds returned 14.3 percent over 2015.
Renaissance Technologies, the hedge fund firm started by Mr. Simons in 1982, uses computers to track and outsmart the stock market. It is a strategy that has worked well. The main Renaissance funds gained between 15.6 percent and 16.5 percent.t and 16.5 percent.