Global investors have tempered their optimism about the U.S. and world economies and plan to put more of their money in cash and less in commodities during the next six months, a Bloomberg survey found.

Almost one in three of those questioned said they will hold more cash, and 30 percent intend to reduce investments in commodities, according to a quarterly Bloomberg Global Poll of 1,263 investors, analysts and traders who are Bloomberg subscribers. Both results were the highest since the survey began asking the question last June.

Forty percent expect oil prices to fall in the next six months, the first time respondents have felt that way since the inception of the poll in July 2009.

The “big stimulus game is over,” said Bill O’Connor, a poll participant and founder of the Sagg Main Capital hedge fund in New York, in explaining why he’s moving money into cash as the Federal Reserve winds up its bond-buying program and U.S. lawmakers look to cut the budget.

Fewer than four in 10 of those surveyed described the U.S. and global economies as improving, down from about 50 percent who felt that way in January. U.S. economic growth slowed to a 1.8 percent annual pace in the first quarter of this year, down from 3.1 percent in the final three months of 2010. Home prices fell in more than three-quarters of U.S. cities in the first quarter of 2011, according to the National Association of Realtors.

The poll, conducted May 9-10, also found that investors’ ardor for stocks is cooling. Two in five intend to increase their exposure to equity markets in the next six months, down from almost three in five in January. U.S. investors in particular have become less keen on stocks, with 37 percent saying they are increasing their exposure to equities, down from 57 percent in the previous poll.