Chinese indexes have posted steep losses, with market volatility rising so far this year, but U.S. stocks are up and volatility in the American market is down.
"Indeed, the U.S. — at least the U.S. equity market — appears to have largely skirted the effects of the trade war," Rudean added in the report.
As a comparison, the American Russell 1000 is up about 10 percent in 2018 while China's CSI 300 — an index measuring 300 stocks on the Shanghai and Shenzhen exchanges — is down about 15 percent in the same period. The Russell 1000 represents the top U.S. companies by market capitalization.
In fact, the sensitivity of the Russell 1000 to the GSCI Non-Energy Index has been trending downward since 2010, indicating that changes in broad commodity prices had a declining impact on the U.S. market, wrote Rudean.
In contrast, the CSI 300's sensitivity to commodities fluctuated, Axioma found.
Non-energy commodity prices started falling after the trade war between the world's two largest economies heated up in June. The GSCI Non-Energy Index is down 4.5 percent so far this year.
The U.S. market's declining sensitivity to non-energy commodities could be due to reasons such as deregulation, tax cuts and protectionist policies such as tariffs boosting investor sentiment in the U.S. market.
Those factors "may have decoupled the moves of the market from the moves of the global non-energy commodities," Rudean told CNBC.
"Also, as the U.S. market rose after November 2016, it may have moved towards stocks that are less sensitive to the commodity market. For example, technology stocks became a bigger part of the Russell 1000, and their lower sensitivity to commodities may have also drawn down the index sensitivity to commodities," she added.