Wealthy U.S. investors expressed declining market confidence in May, according to a Spectrem Group survey.

The Spectrem Millionaire Investor Confidence Index, which tracks the sentiments of investors with $1 million or more, dropped two points in May to 6. The Spectrem Affluent Investor Confidence Index, which tracks those with more than $500,000, dropped three points to -1, falling back into negative territory after pulling out of that range for three months.

The survey was conducted May17 to May 23. While the stock market remained steady during that period, it was also marked by rising tensions with China, increasing political rhetoric about impeachment in the wake of the Mueller investigation, and a more aggressive U.S. stance toward Iran, according to Spectrem.

Spectrem said that high-net-worth investors are concerned over the lack of progress in resolving the ongoing U.S.-China trad  conflict, and that they plan to allocate more assets to bonds and cash.

Spectrem President George H. Walper, Jr. said in a news release that despite favorable market performance, investors were clearly concerned about the impact of U.S. politics and foreign policy on future market performance.

“A prolonged trade war and its likely impact on American corporations [will also] impact investors and their household finances,” Walper said in a news release. “It's fair to expect investors to be conservative during this type of environment.”