How much is Fed aid to U.S. corporate profits worth?

Many on Wall Street believe the Federal Reserve's monetary policy is behind record corporate earnings and the stock market's surge to all-time highs this year.
But how much is a burning issue for investors who wonder how the economy and stocks will perform once the Fed eventually eases its buying of $85 billion a month in bonds and eventually allows short-term rates to climb.
Some believe the influence of the Fed's policy, known as quantitative easing, has been particularly important to the performance of the benchmark Standard & Poor's 500 Index .SPX.
"People underestimate the extent to which quantitative easing has benefited the S&P," said Robbert van Batenburg, director of market strategy at brokerage Newedge USA LLC in New York. He called the effect akin to "an athlete on steroids."

http://www.reuters.com/article/2013/07/25/us-usa-earnings-qe-analysis-idUSBRE96O03U20130725