If China's growth did slow more sharply, the impact on the U.S. would be minor. Goldman Sachs analyst David Kostin says a 1 percentage point drop in China's annual economic growth would shave 0.06 percent off U.S. gross domestic product. That impact is already showing up in second-quarter reports by companies such as Caterpillar, 3M and United Technologies, suggesting it would be concentrated among industrial companies.
That suggests the 2 percent decline in U.S. stock market averages today is overdone.