The third and latest round of quantitative easing rolled out earlier this month by the Federal Reserve will sweeten MBS demand far above supply, but it will ultimately provide only a negligible boost to mortgage refinance activity, analysts say. The Federal Open Market Committee announced QE3 on Sept. 13, making a commitment to buy an additional $40 billion in agency MBS a month and saying that it would continue buying “if the outlook for the labor market does not improve substantially.” The New York Fed has been buying about $27.9 billion of agency MBS per month since October 2011 in an effort to reinvest principal payments from its MBS holdings back into the mortgage securities market. An analysis by Bank of America Merrill Lynch this week found...