KEY POINTS
  • Janet Yellen, whose last day at the Fed was Friday, told CBS that stock market valuations are "high," though she's not sure if they're in a bubble.
  • The comments came amid an aggressive market sell-off that saw the Dow industrials lose 666 points Friday.
  • Yellen has ended a 14-year career at the Fed, the last four as chair.
  • During her tenure, the S&P 500 surged 53 percent and the Fed hiked its benchmark interest rate target five times.

Janet Yellen ended her long career at the Federal Reserve with concerns over how high the stock market has surged under her watch.

The has soared 315 percent since the March 2009 bear market lows and about 53 percent since she took over as chair of the central bank in 2004.