Here are a few reasons why an early departure would be appropriate: Long gap between FOMC meetings: There's an unusual amount of space in between the Fed's meeting on Jan. 31 and the one on March 28. Greenspan will thus be presiding over a meeting that casts a long shadow in a quarter that often sets the tone for the entire year for the economy. It also brings Bernanke's decision-making closer in time to the midterm elections. Little time until semiannual report to Congress: Twice a year, the Fed chairman is required to deliver a semiannual monetary policy report to Congress; the first is typically delivered in February. While there's no doubt about Bernanke's ability to prepare high-caliber testimony, it would likely more accurately reflect the views of all of the members of the FOMC if he were to have more time with them in advance. Otherwise, Bernanke's testimony could lean a bit too heavily toward his personal views. Uncertainties would clear more quickly: There are numerous uncertainties with respect to how Bernanke will lead the Federal Reserve, including for example the construction of policy statements, the extent to which he might deploy a strategy of inflation-targeting and how he would react to events as they occur. Continuity: Bernanke stressed continuity in his acceptance speech at the White House and it would thus be quite a symbolic gesture for Greenspan to hand the reins over early to his able successor. Given the history and some of the compelling factors that would justify an early departure, it isn't necessarily a given that Greenspan will preside over the Jan. 31 FOMC meeting. True, Bernanke was appointed to fill a seat on the Board of Governors that won't be vacant until Greenspan's term expires, but there are two other empty governor seats that Bernanke could take without comprising any prospect for a lengthy stay as Fed chairman. Indeed, one of the empty seats is the seat that Bernanke vacated, with a term that doesn't expire until Jan. 31, 2018, when Bernanke could theoretically be appointed for a second term and stay on to become the longest-serving Fed chairman ever.