According to the Wall Street Journal, a number of sponsors are frustrated with the lower than expected numbers of people visiting the elaborate pavilions they have set up on Beijing's Olympic Green.
Lenovo, Samsung, Adidas, Coca-Cola and McDonald's are among the sponsors to have a presence on the Green, which is six times the size of the Green in Athens and three times the size of Central Park
The Journal claims sponsors were expecting 200,000 visitors per day, but have seen only 20% of that number because Chinese officials are only allowing in people with tickets for the venues around the Green and not those with day passes.
No sponsor was quoted by the paper apart from an Adidas spokeswoman who said: "It would have been nice to see more numbers earlier, but we are seeing a growing trend." A McDonald's spokeswoman declined to answer questions about the lack of people on the Green.
A spokesman for the Beijing Olympic Committee said it was "aware of the issue" and it was planning to invite more people to the Green.
Meanwhile, swimmer Michael Phelps, nicknamed the "human dolphin", established himself as the US's darling by winning the most golds of any Olympic athlete. He won his tenth gold in the 200m butterfly and is on course to break the record for the most gold medals at a single Games.
Visa, which already had a relationship with Phelps through its Team Visa programme, ran a special congratulatory ad in NBC's first commercial break following his achievement.
Kevin Burke, head of global consumer marketing of Visa Inc, said: "Michael Phelps truly embodies the spirit of our 'Go World' campaign that celebrates memorable Olympic moments and the extraordinary athletes who achieve them."
Phelps has been tipped by a US talent agency as one of the athletes most likely to be signed as a brand ambassador following the Games.
Scott Sanford, senior client director at Davie Brown Talent, said: "Phelps is exactly what marketers are looking for in an Olympic athlete: focused but still fun, authentic, hard-working, handsome."
Sanford also praised swimmer Natalie Coughlin, saying: "Natalie's spent a lot of time on the medal stand, which has kept her in the spotlight. Off of it, her personality has really shone through. I think she's connected with many Americans."