Sun's popularity in his homeland has skyrocketed after he won the 400- and 1,500-meter freestyle at London's Aquatics Centre and will rake in around $18 million over the next year as part of his arrangement with three major companies.
However, under the terms of his contract with the Chinese swimming authority he will have to hand over one third of those earnings to other members of the Olympic team who are not so well rewarded.
[ Related: Sun Yang wins 1,500 free with world record ]
His handout will be welcomed by the less well-known swimmers, many of whom receive just a small stipend from their country's governing body, although all their training and living costs are covered.
Chinese media reports told how Sun's wealth will be boosted by Coca Cola, shoe company 361 Degrees and dairy goods manufacturer Yili. A series of smaller deals will increase his earnings further. Billboards in major cities such as Beijing and Shanghai already have sprung up with his face on them, alongside pop stars and actors.
Like the majority of Chinese athletes, Sun only gets to keep one third of any prize money or endorsement packages himself. As well as treating his teammates, another third must go to the Chinese swimming program.
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Chinese swimming officials would not comment on the money-sharing program, but it was confirmed by Xinhua, the official state media agency.
The Chinese government has defended its stance on demanding a percentage of its athletes' income, insisting it is necessary to continue to develop fresh talent.
[ Related: U.S. likely to top China in the medal count ]
It also claimed that the cost of turning Sun into a world-class swimmer and training him from childhood had reached $1.57 million, a revelation that caused a mild uproar in China and led to public questioning of whether the nation's pursuit of sporting glory was worth the financial investment needed.
Part of that was spent on Australian Denis Cotterell, considered to be among the best swimming coaches in the world and a specialist in long-distance events. Cotterell was tasked with mentoring Sun to Olympic glory, but did not come cheap.
"What the Chinese offered me for a month, I could live on for a year," Cotterell said.
Athlete endorsement deals in China have greatly increased in recent years as the country's economic power continues to grow. Hurdler Liu Xiang was richly rewarded after claiming gold in Athens in 2004 and is reported to earn $14 million a year from sponsors.
Basketball's Yao Ming and former French Open tennis champion Li Na have both accrued serious wealth from being the face of several products and companies, but those deals were primarily due to their efforts outside the Olympic arena.
Sun's deal is the highest for any athlete in a sport where Olympic gold is the highest honor possible. At just 20 years old, it is expected that he will return in Rio in four years' time and possibly in 2020 as well.
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