This chart shows U.S. stocks dependent on China

Published Tue, Jul 7 20152:44 PM EDT

The raging China bear market is finally tightening its grip on the U.S. stock market, and it may only get worse as large domestic companies with big sales to the country come under pressure. If you need evidence of this, look no further than a one-day chart of the S & P 500 with the iShares China Large-Cap ETF laid on top of it through 2 p.m. ET Tuesday. Source: Barchart.com These two are a mirror image. That wasn't the case before. This China ETF, which contains the largest Chinese stocks that trade in Hong Kong, is off 15 percent in one month. The S & P 500 is down only 1 percent. If history is any guide, odds are that the decline for U.S. stocks should catch up. There have been 21 other occasions in the last decade when the iShares China ETF dropped more than 10 percent in one month, according to Kensho, a quantitative tool used by hedge funds. During those periods, the S & P 500 dropped, on average, 5 percent. And during those troubled months for Chinese equities, the S & P 500 managed to trade positively only four times. Read More No one on Wall Street likes Shake Shack Shares of U.S. companies that sell raw materials to the globe were the worst performers Tuesday on fears that China's stock market crush will lead to a slowdown for the global economy. "Consumer names may not be as impacted as others, but I sure don't want to own stocks dependent on commodities such as Freeport-McMoRan ," said Stephen Weiss of Short Hills Capital Partners. But the second-worst sector performer was technology, and that's an industry with a lot at risk if China's economy starts to slow. "Tech is the holdout that's not pricing in an Asia-Pacific slowdown, led to the downside by China," said Steve Cortes, macro strategist at BGC Partners. "I see tremendous risks for spaces like semiconductors." The five U.S. companies with the largest 2014 sales to Asia as a percentage of total revenue are all from the technology sector, according to Howard Silverblatt of S & P Dow Jones Indices. (Companies don't break out sales in China specifically.) The two companies with the largest sales in Asia by dollar amount are also from the tech industry: Intel and Apple . In order to find some other names that could get hit further on this China-led drop, CNBC Pro went back to the Kensho screen mentioned above, which looked at what happened to the S & P 500 when the China ETF dropped 10 percent in one month. The U.S. stocks that dropped signficantly during that one month period included American International Group , Joy Global , Transocean , Seagate Technology and General Motors . Forget Greece. This could be the real risk for U.S. stocks going forward.

Investors look at computer screens showing stock information at a brokerage house in Qingdao, Shandong province, China.

China Daily | Reuters

The raging China bear market is finally tightening its grip on the U.S. stock market, and it may only get worse as large domestic companies with big sales to the country come under pressure.

If you need evidence of this, look no further than a one-day chart of the S&P 500 with the iShares China Large-Cap ETF laid on top of it through 2 p.m. ET Tuesday.

S&P 500 vs. China ETF Tuesday (Through 2pm ET)

Source: Barchart.com

These two are a mirror image. That wasn't the case before.

This China ETF, which contains the largest Chinese stocks that trade in Hong Kong, is off 15 percent in one month. The S&P 500 is down only 1 percent.

If history is any guide, odds are that the decline for U.S. stocks should catch up.