It is not illegal for the Federal Reserve or the U.S. Treasury to buy S&P 500 futures. This type of intervention could explain some of the unusual market action in recent months, with stock prices grinding higher on low volume even as companies sold huge amounts of new shares and retail investors stayed on the sidelines. Some market watchers have charted that virtually all of the market's upside since mid-September has come from after-hours futures activity. [These claims are] based on an analysis of the possible sources of the $600 billion in net new cash that was needed to boost the U.S. stock market capitalization by $6 billion since March. The usual sources, such as retail investors and pension funds, could muster only about $100 billion. The rest had to come from somewhere. The Fed has been openly buying some $1.7 trillion worth of long-term bonds since last March, which is something it hasn't done since the 1950s. Today, the Fed is making purchases to support housing by keeping mortgages cheap. As these purchases are phased out over the next few months, long-term interest rates will continue to move higher. This will cause long-term bond prices to fall, causing this new bond bubble" to deflate. Stock investors will benefit, just as they did in the 1950s and 1960s as capital was moved from falling bonds into rising stocks.