Federal Reserve Chair Janet Yellen (L) congratulates Fed Governor Jerome Powell at his swearing-in ceremony for a new term on the Fed's board, in Washington in this handout photo taken and released June 16, 2014.

Janet Yellen's final days as head of the Federal Reserve are at hand.

The Federal Open Market Committee, which sets monetary policy for the U.S. central bank, decided this week to select Jerome Powell as its new chairman effective Saturday. He will be officially sworn in Monday.

The move was a formality considering that Powell already has been confirmed by the Senate as the new Fed chair, but it does delineate how the handoff of power will occur.

Yellen has led the Fed since February 2014, but President Donald Trump chose not to reappoint her. She becomes the shortest-serving Fed chair since the late 1970s.

After Trump made his choice of Powell public, Yellen said she would not stay on the FOMC.