Chamber of Commerce in Shanghai showed a majority of firms believed that competition had intensified, while the number who said they were profitable in 2012 dropped to 73 percent from 78 percent in 2011.

This reflects the challenge for global firms looking to boost profits in faster-growing economies such as China, and underlines the impact of China's slowdown in 2012, where GDP grew at its slowest pace in 13 years.

The 420 U.S. firms surveyed identified rising costs, human resources constraints and heightened domestic competition as the main business challenges, said the report.