Selon Goldman Sachs il existe 3 raisons de croire en un Quantitative easing 3.

“1. The improvement might not last.

With real GDP growth tracking just 2% in the first quarter and signs that at least some of the recent strength is probably due to the unusual warm weather and perhaps some seasonal adjustment distortions, question marks still surround the true pace of activity growth. In addition, there are still several actual or potential “headwinds” for growth, including a reduced boost from inventory accumulation, the recent increase in oil and gasoline prices, continued risks from the crisis in Europe, and the specter of fiscal retrenchment after the presidential election.

2. Even if the improvement does last, faster growth would be desirable to push down the unemployment rate more quickly.

Fed officials believe that the level of economic activity and employment is still far below potential. This means a large number of individuals are involuntarily unemployed, which not only causes hardship in the near term but may also translate into higher structural unemployment in the long term…This creates an incentive to find policies that speed up the return to full employment.

3. Not easing might be equivalent to tightening.

At a minimum, the bond market currently discounts some probability of QE3. This has kept financial conditions easier than they otherwise would have been, which has presumably supported economic activity. A decision not to ratify expectations of QE3 could therefore result in a tightening of financial conditions.”

Source: Goldman Sachs