The FOMC has a big decision to make. Last fall, it announced Operation Twist, an asset purchase program wherein the central bank buys $45 billion of long-term Treasury bonds each month and sells short-term notes to "sterilize" the purchases by keeping the overall size of the central bank's balance sheet the same.

In September, the FOMC announced open-ended QE3, which added $40 billion per month of purchases of mortgage-backed securities to the Fed's balance sheet expansion efforts.

Now, the Fed has run out of short-term notes to sell, and Operation Twist is set to expire at year-end.

The Fed's decision on what to do next will set the tone for monetary policy in 2013.

QE4

Wall Street economists expect the Fed to fill the hole left by the expiration of Operation Twist by continuing to by the same amount – $45 billion per month – of long-dated Treasuries, just without the sterilization.