(Bloomberg News) Blackstone Group LP's Byron Wien, whose prediction for the U.S. economy and stock market in 2011 proved too optimistic, said he may need to lift his estimate for the Standard & Poor's 500 Index for this year.

Wien, chairman of Blackstone's advisory services unit, said in January in his annual "10 Surprises" list the benchmark gauge for U.S. stocks may exceed 1,400. He said today in a Bloomberg Radio interview he may have to raise the projection.

"1,400 when the market was 1,250 at the beginning of the year was a reasonable target, a conservative target," Wien said in an interview today on Bloomberg Radio's "Bloomberg Surveillance" with Tom Keene. "But I think we could well exceed it. Look, S&P 500 operating earnings are going to be in excess of $100. Very often, almost always, the S&P 500 sells at 15 times, that would take you over 1,500."

The S&P 500 has jumped 7.4 percent this year to 1,350.50 through yesterday, as investors gained confidence the European debt crisis won't trigger a global recession and U.S. economic data improved. Wien had said in January 2011 the S&P 500 would rise toward 1,500 by year-end. The index was almost unchanged in 2011 at 1,257.60.

The measure is trading at 14 times profit in the last year and 13 times projected earnings for 2012, according to data compiled by Bloomberg.

"What's jump-starting the market is the economy is better than the consensus thought it was going to be at the beginning of the year," Wien said.