FORTUNE — As he gears up for the final stretch in the marathon that is the Republican nomination campaign, Mitt Romney has no shortage of eminent financiers to call on — for advice or money. Billionaire hedge fund titans such as Julian Robertson of Tiger Management, Louis Bacon of Moore Capital, and John Paulson of Paulson & Co. have all lined up behind the front-runner. Steve Schwarzman, the co-founder of private equity giant Blackstone (BX), recently held a high-level fundraiser for Romney at his Park Avenue apartment. Romneys old friends at Bain Capital, the buyout firm he co-founded in 1984, have also been generous in their support. But perhaps none of Romneys Wall Street supporters will be more crucial to the candidates success, or have more influence on his thinking, than Paul Singer.
Singer is the founder of a $19 billion hedge fund called Elliott Management. And he has a well-earned reputation as one of the smartest and toughest money managers in the business. Over the past 35 years Singer, 67, has produced an extraordinary 14% average annual return after fees, nearly double the price appreciation of the S&P 500 (SPX). He has achieved that record in large part by buying the debt of bankrupt companies and nations — a strategy that has earned him considerable opprobrium in some circles. His firm, which is engaged in a costly, protracted legal war with Argentina over its defaulted sovereign debt, is so influential that fear of its tactics helped shape the current Greek debt restructuring. Among the sophisticated investors who have placed their confidence in Singer is Mitt Romney himself. According to Romneys financial disclosures, the trust managing his more than $200 million fortune has at least $1 million invested with Elliott.
In recent years Singer has emerged as a quiet force in the Republican Party. He is one of a handful of moneymen who have given $1 million to the Romney super PAC Restore the Future, which so far has raised $37 million and spent some $34 million. Singer has also donated more than $220,000 to 31 Republicans in national races across the country since Barack Obama became President. Over the past three years he has given nearly $2 million to Republicans in local races in states as far-flung as Florida, Michigan, California, and Texas. But his value goes far beyond his own deep pockets. Singer is known as a major Republican bundler, with a large network of rich donors ready to follow his lead. All the candidates come to pick his brain, says one party insider.
