Kohn could stay on at the Federal Reserve until Sept. 1

He will participate in all board activities and the next policy-setting Federal Open Market Committee meeting, scheduled for June 23. He might also participate in the Aug. 10 meeting. 

The 67-year-old Kohn, who has worked at the Fed for 40 years, was appointed to the Board in 2002 and moved into the vice chairman's position in 2006. 

Obama has nominated two others for vacant seats on the Fed's board — Peter Diamond, an economist from the Massachusetts Institute of Technology and Sarah Bloom Raskin, Maryland's state banking regulator.