More than 17 million people live in Beijing, China, the host city for the Summer Olympics that open Friday. That is more than the population of the past four host cities — Athens, Sydney, Atlanta and Barcelona — combined. China counts 1.3 billion residents, more than any country on Earth.

Never before has an Olympics been staged in a market so big — and so underserved. Though capitalism has been a fact of life in China for years, no brand category has been captured the way, say, Wal-Mart dominates the U.S. retail market. Which means: Olympic sponsors are staring at a once-in-a-lifetime opportunity to engage and snare the Chinese consumer. Do it right, and the payoff could be massive.

According to IEG, a sponsorship tracking firm in Chicago, the host organizing committee in Beijing has secured about $740 million in sponsorship revenue — only $56 million shy of the combined amount brought in by the 2004 Athens committee and the 2002 Salt Lake City committee during the Winter Olympics. Sponsorships handed out by The Beijing Organizing Committee of the Olympic Games, or BOCOG, are coveted because they give the companies rights to use the Olympic name when promoting their products within China.