Wall Street advanced Wednesday after the Federal Reserve added a modest amount of cash to the banking system and investors went in search of bargains among hard-hit stocks.

The market revealed its nervousness, however. The Dow Jones industrial average bobbed above and below the 13,000 mark throughout the day amid conflicting announcements from the New York Federal Reserve over its repurchase plans, a brief surge in energy prices, and the potential for more bad news from hedge funds and mortgage lenders.

The Fed ultimately said it would accept a “repo” of $7 billion, in which it buys that amount in securities from dealers, who then deposit the money into commercial banks. The repo followed the Canadian central bank’s announcement that it has temporarily expanded the list of eligible collateral it will accept for repos. Central banks worldwide have supplied billions of funds to banks over the past week to make cash available for lending and keep interest rates stable amid signs that credit was drying up. [MORE]