Three years later, Arum became the lawyer for the man who beat Liston, Muhammad Ali. Arum promoted 26 of Ali’s bouts, making a fortune, and then made another in the 1980s from such great middleweights as Tommy Hearns, Sugar Ray Leonard, and Marvin Hagler. Throughout the next decade, while King and his crown jewel, Mike Tyson, presided over the heavyweight division, Arum guided the career of the young De La Hoya and turned him into a fistic Fort Knox.

With Arum pulling the strings, De La Hoya established his career by crushing a series of carefully picked patsies before knocking out super-featherweight Jimmy Bredahl for his first world title. He had been a pro for a little more than 18 months. From then on, De La Hoya made a minimum of $1 million a fight, an unprecedented sum for the lower-weight divisions, let alone for a fighter with only a dozen pro bouts.

De La Hoya was the boxer that the Hispanic community—and advertisers—had been waiting for. Spooked by Tyson’s cannibal mystique, Madison Avenue recoiled from virtually all prizefighters except De La Hoya. Radiating charisma, De La Hoya pitched everything from aftershave lotion to milk. His status as a Latin heartthrob was promoted by Arum, who planted women with marry me, oscar! signs in televised press conferences. In 1997, De La Hoya’s $37 million in earnings made him, according to Forbes, the third-best-paid athlete in the world.

By the end of the century, the freewheeling, free-spending De La Hoya was saddled with numerous lawsuits and burning through his money as fast as he made it. He squandered millions in casinos, sometimes losing as much as $300,000 in a single sitting. After one of De La Hoya’s fights in Las Vegas, Arum asked Caesars Palace to impose a $250,000-a-night credit limit on the fighter to ensure that he would leave town with most of his boxing winnings intact.

At the same time, the undefeated champion had begun to question the way his purses were being carved up. He says Arum explained very little about the intricacies of pay-per-view, closed-circuit broadcasts, and sponsorship percentages. He grew warier in September 1999 after a welterweight title bout with Felix “Tito” Trinidad of Puerto Rico. Arum and King, who represented Trinidad, had negotiated the fattest nonheavyweight deal ever. De La Hoya lost, in a split decision, his title and his temper: His take was $23 million; Arum’s, $12 million. “I thought, There’s something wrong here,” De La Hoya says.

He hired his own agent and accountant and set up Golden Boy Enterprises to oversee his fights and endorsements. In search of a banker to help him run the operation, he turned to Richard Schaefer, then the deputy C.E.O. of UBS’s private-banking operations in the U.S., who happens to be married to the aunt of De La Hoya’s closest childhood buddy. Schaefer, now 46, isn’t anyone’s idea of a boxing whiz kid. Born into a banking family in Bern, Switzerland, he’s a mild, sober fellow with an exceedingly limited understanding of the fight game. Yet since Schaefer joined the company, in 2001, Golden Boy has shown consistent double-digit growth. “As a business, the sport is a mismanaged asset that’s stuck in the 20th century,” he says. “To me, boxing was a stock out of favor. We had the chance to buy low and sell high.”

Schaefer, who says that his clients included “nearly half of the Forbes 400 west of the Mississippi,” persuaded De La Hoya to quit gambling and set about learning the vagaries of the sport. Apprenticing under Arum, he learned quickly. De La Hoya insisted that Schaefer be allowed to sit in on meetings, and Arum taught the banker how to run a boxing show, ferret out sources of revenue, and negotiate with venues, sponsors, and TV networks.

“I knew about integrity and transparency and how to deal fairly with people, all of which were new and unknown concepts to boxing,” Schaefer recalls. Eventually, he told Arum that De La Hoya wanted to dump him as a promoter and go it alone. “Bob didn’t believe me at first,” says Schaefer. “When he did believe me, he started screaming. You can’t blame him for wanting Oscar to remain his cash cow.” (Arum denies reacting this way.) De La Hoya sued to get out of his contract, but the Golden Boy’s victory in federal court, as well as his reputation, was tarnished by a boast that he had just “defeated one of the biggest Jews to come out of Harvard.”

Still, the company may not be as clean as its reputation. Last year, at a steak house in Beverly Hills, Schaefer and De La Hoya handed boxer Manny Pacquiao—Golden Boy’s opponent in the ring this month—a suitcase stuffed with $250,000 in cash to get him to sign a seven-fight contract. Though Schaefer and De La Hoya broke no laws, the hand­off of 12,500 twenty-dollar bills seemed like a move straight out of the Don King playbook. And as it turned out, Golden Boy was outbid. Arum later paid $1 million to Pacquiao and won a court battle for the right to promote him, and the cash was returned.

For his part, Schaefer has worked to bring corporate support back to the ring. “Luring sponsors wasn’t hard in Ali’s day,” he says. “But now sponsors have choices, and frankly they don’t need the negative perception that comes with boxing.” Yet he managed to persuade five Fortune 500 companies to sponsor the Mayweather fight in 2007 and publicize it at their retail stores. The cash and advertising by such formerly boxing-­unfriendly sponsors as Southwest Airlines, Tecate beer, and Bacardi-brand Cazadores tequila were valued at more than $10 million.