During the last election cycle, Gilder gave Republicans $250,000 of his own money. But the donations represented just a fraction of the cash he marshals for supply-side politicians. In the mid-1980s Gilder founded the Political Club for Growth, a group of Wall Street conservatives who pooled their contributions to increase their influence. The more-visible Club for Growth, a political action committee modeled on the liberal Emily's List, was created in 1999. Last year, club members combined their contributions into million-dollar "bundles" for several candidates, several of whom later appeared at press events as the Club's "rising stars" in Congress.

In January, the club promised to spend another $1 million on advertising in support of Bush's tax cut proposal. "What's needed is a sort of pressure group that puts direct pressure on members of Congress to enact legislation using a carrot-and-stick approach," says Stephen Moore, another founder of the club and a senior fellow at the libertarian Cato Institute. The carrot is cash, and Gilder holds one of the sticks.

In a rare interview with the National Journal in 1995, Gilder was unabashed about how politics affect his personal fortunes. He described leading his clients into the stock market during the late 1970s in anticipation of a capital gains tax cut. When it came, the market surged and his investments rose -- only to be driven to further heights by Reagan's income-tax cuts. Gilder came to believe that lower taxes meant a better environment for investing. "If you are an investor you want to watch tax rates, especially capital gains rates," Gilder told the Journal. "If rates are going up, that's not good for the economy."

More recently, Gilder has trumpeted another proposal that would benefit his investment portfolio: the privatization of Social Security. Such a plan, according to analyst estimates, could pump $6 billion of public retirement funds into private markets each month. It would also create an unprecedented political incentive for politicians to cater to the wishes of Wall Street, lest they hurt their constituents' new portfolios.

Gilder has also been an active supporter of plans to privatize another lucrative service: public education. As far back as 1993, Gilder and his former wife, Virginia, gave $100,000 to an ill-fated proposal in California to promote vouchers for public school students who transferred to private classrooms. In 1998, Gilder gave at least $25,000 to a political action committee lobbying for more charter schools in New York. Amway founder Richard DeVos Sr.(No. 12, $764,500), buyout king Theodore Forstmann (No. 210, $251,000), and Wal-Mart heir John Walton (No. 396, $153,250) have all financed similar efforts to bring market principles to public education.