This Wall Street Journal article discusses the repurchase agreement market or the "$4.5 trillion securities repurchase, or 'repo' market". The Journal speculates, "As with other kinds of short-term financing recently, the money is drying up. Investors and financial institutions who lend in this market have become worried about losing money on securities used as collateral. Determined to protect themselves, they're pulling back from offering repo financing to each other." (See also today's News, which says S&P has affirmed that rolling Bear Stearns repo is now okay in AAA money funds.)