Insurers are growing more pessimistic about the economy and markets, and the risk of a U.S. recession has become one of their chief concerns, according to a new survey.

Fifty percent of company heads said they felt investment opportunities are getting worse, up from 36 percent last year.

Those figures come from the seventh annual Goldman Sachs Asset Management (GSAM) insurance survey.

The 300 insurance CIOs and CFOs surveyed for the report showed a shift in sentiment from a year earlier, according to GSAM. In 2016, the group's top concerns were political turmoil and an economic slowdown in China. In the latest report, the top concerns were a possible global economic slowdown and a U.S. recession.

Those worries seemed to be reflected in their investment outlook, with 17 percent of respondents saying they are looking to "de-risk" their portfolio, up from 10 percent a year ago. Sixteen percent said they were looking to increase risk, down from 26 percent a year ago. GSAM noted it's the first time since the survey started seven years ago that more respondents are decreasing rather than increasing risk.

“2018 marked the return of market volatility for the first time in nearly a decade, rattling markets and leading insurers to question the current investment landscape,” said Michael Siegel, GSAM’s global head of insurance asset management, in a press release. “While low returns have been the main concern in the insurance industry for the last several years, the changing economic environment is leading to more focus on protecting portfolios in the event of a downturn.”

The insurance executives, however, were not completely running away from the markets, at least for the short term. The survey found that 77 percent of respondents believe that the S&P 500 will have a positive return in 2018.

The survey also showed growing interest among insurance companies in "higher returning, less liquid asset classes such as private equity, infrastructure debt, commercial mortgage loans and middle market corporate loans and a movement towards floating-rate assets," the report said.

Also, for the first time in several years, insurance executives expressed significant concern about interest rates and inflation, with many correctly predicting that Treasury yields would break the 3 percent barrier (something it did this week). "Eighty-five percent of insurers agree inflation is a concern over the next five years, and 65 percent predicted the 10-year U.S. Treasury yield will exceed 3 percent by the end of 2018," the report said.

Other findings also emerged from the survey:

• ESG investing is getting more attention from insurance companies, with 40 percent of respondents saying they take environmental, social and corporate governance issues into account when making investments, up from 32 percent a year ago.

• The insurance industry continues to embrace big data and artificial intelligence, with 15 percent of global insurers using it in their portfolios and 40 percent considering implementing it in the future.

• Insurers seem to be taking a wait-and-see approach to cryptocurrencies. They “currently do not play a role in the investment portfolio, yet a third of companies feel it is too early to determine if there is a role for cryptocurrencies," the report said.

GSAM received 300 responses from CIOs and CFOs across life, property and casualty, multi-line, reinsurance and health insurers, representing more than $10 trillion in global balance sheet assets, the company said.