Over the past 20 years, the average one-year real rate has been a negative-0.8%. If U.S. inflation over the next 12 months is higher than over the past 12 months, the real one-year Treasury yield would be lower than 1.

The Fed kept its key rate unchanged for the fourth straight meeting Wednesday, and said the economy is expanding at “a solid pace."

Four meetings and six months have elapsed since the Fed last adjusted interest rates. The federal funds rate stands between 4.25% and 4.5%, preserving much of a sharp increase imp