The search is over. The Obama administration has tapped now-former Fannie Mae (FNM) CEO Herb Allison to replace Neel Kashkari as head of the government's $700bn Troubled Asset Relief Program, effectively granting him the title assistant secretary for the Office of Financial Stability -- so long as he is confirmed by Congress. Treasury secretary Timothy Geithner has been searching for months for someone to run TARP, but has seen senior posts become increasingly tough to fill, as candidates withdraw or don’t pass muster in the vetting process. Last month, hedge-fund manager Frank Brosens — largely expected to take Kashkari’s now-temporary role — withdrew for what has only been described as “personal reasons.” Allison, 65, is the former chairman of investment company TIAA-CREF and was a longtime Merrill Lynch & Co. executive. He was appointed as chief executive at Fannie Mae after the government placed both mortgage finance giants into conservatorship last year. The GSE thanked Allison today for his "tremendous contributions to Fannie Mae." "He has guided the company most ably through a very challenging period. We wish him all the best in his new position," said Philip Laskawy, chairman of the board at Fannie Mae. Fannie Mae also said today that Michael J. Williams has been appointed to succeed Allison as president and CEO. Williams most recently served as executive vice president and COO at the GSE. Write to Kelly Curran at Disclosure: The author held no relevant investment positions when this story was published. Indirect holdings may exist via mutual fund investments.