It is less likely for the U.S. Federal Reserve to adopt the third round of quantitative easing (QE3) this year, Prudential analysts said at the Prudential's Midyear Global Markets and Economic Outlook panels on Tuesday.

"It is a close call," said Edward F. Keon, managing director and portfolio manager for Quantitative Management Associates, "but I think it is less likely for Fed to do QE3 in the second half of this year. "

He thought U.S. long-term interest rates were already record low, any more bonds buying would be unlikely to low it much further.

Besides, although U.S. economic growth was slowing down, "it will continue to grow at least a little in the second half, so the policy-makers will be reluctant to use the last big weapon they have available to them. "

Keon's opinion was echoed by John Praveen, managing director and chief Investment Strategist of Prudential International Investments Advisors LLC. Praveen also thought QE3 was unlikely this year.

He cited two main reasons for the "less possibility for QE3". He predicted a 2-percent growth rate for U.S. economy in 2012, which "is weak as it is", but "not weak enough to trigger a QE3".

And another important reason was that before the U.S. presidential election in November, the Fed basically only has two months to do something. And he thought in that two months, the data was not going to be so bad to force the Fed to adopt QE3.

Praveen also pointed out that the 10-year U.S. Treasury yield had dipped to a very low level of around 1.6 percent, which had already been a very easing environment for the economy. "So if the bond yield of 1.6 percent is not supporting the economy, will QE3 support the economy?"

But both of them said, if the European crisis worsened and triggered a global recession, the odds of QE3 would definitely increase. And the possibility of U.S. fiscal cliff could also increase the odds.

"I think it's more likely (for QE3) to occur if we get a further slowdown in the U.S. economy or much bigger problems coming out of Europe," Keon said.