New York Fed unveils 'overnight bank funding rate' as longtime benchmark fades.

Both the Japanese and European central banks recently moved benchmark rates into negative territory.

Both the Japanese and European central banks recently moved benchmark rates into negative territory.

Chicago Fed president Charles Evans is nervous about the December decision, and anticipates rates may remain below 1 percent at the end of 2016.

Chicago Fed president Charles Evans is nervous about the December decision, and anticipates rates may remain below 1 percent at the end of 2016.

Segregated balance accounts could help Fed raise interest rates without causing funding issues for banks.

Segregated balance accounts could help Fed raise interest rates without causing funding issues for banks.

Like Alan Greenspan before her, Janet Yellen faces the possibility that the Fed can't actually control long-term interest rates.