White House chief of staff Jack Lew is seen as a leading candidate to replace Geithner. Lew is well-respected in Washington by both parties and served as budget director under both Obama and former President Bill Clinton.
Another person often mentioned as a possible successor to Geithner is Erskine Bowles, a White House chief of staff under Clinton and the co-chief of the White House's 2010 deficit reduction commission.
Both Lew and Bowles would bring an intimate knowledge of the intricacies of the federal budget and could be expected to take a leading role in trying to negotiate a broad budget agreement with Congress. The selection of either would signal that the administration intends to make resolution of the government's deficit problems a priority.
At State, the leading candidates to take over as the nation's top diplomat are Sen. John Kerry, D-Mass., and Susan Rice, the U.S. ambassador to the United Nations.
But Rice has faced criticism this fall from Republicans for providing initial accounts about the deaths of Americans in Benghazi, Libya, that later proved false. The White House has vigorously defended Rice, but the prospect of starting a second term with a contentious confirmation hearing may be unappealing.
Kerry, an early Obama backer, has long coveted the State Department job. He made a well-regarded foreign policy speech at the Democratic convention and even played the role of Romney during campaign debate preparations this year.
Other Cabinet secretaries who have talked about leaving are Attorney General Eric Holder and Transportation Secretary Ray LaHood, the only Republican in the Cabinet. Both have said they would speak with the president before making a final decision.
Second term shake-ups are also sure to hit Obama's West Wing inner circle. Plouffe is expected to be among those departing, while Obama's senior adviser and close friend Valerie Jarrett is staying on.
And if Obama taps Lew for the Treasury Department, he'll have to add chief of staff to the list of vacancies
Associated Press writers Martin Crutsinger, Ben Feller, Ken Thomas and Pete Yost contributed to this report.