GMO’s Jeremy Grantham is planning to cut back on his equity holdings, though he thinks stocks could continue to rise in the short term before hitting a roadblock, TheStreet.com reports.

Grantham told investors at Charles Schwab’s Investment Outlook 2011 conference that stocks are “dangerously overpriced,” according to TheStreet. But he said he expects the S&P 500 to climb to about 1,500 before the end of its big run.

Among Grantham’s concerns for the U.S. economy and markets: high unemployment, income discrepancies, stagnant wages, global warming, dwindling resources, and the decline of educational standards, TheStreet reports. But, he adds, the fact that this is the third year of the Presidential cycle — traditionally a strong year for stocks — bodes well for the short term, particularly given that the economy is “on steroids” thanks to the Federal Reserve’s quantitative easing program. “It always gets a kicker and this is extra,” he said.