Washington | The Federal Reserve’s decision to raise interest rates for the first time in three years this week has markets worried that short-term borrowing costs are about to become more expensive than their long-term counterparts – a classic yield curve inversion.

The yield curve – a graphic which plots the yields on all available bonds from three-month money on the left-hand side to 30-year money on the right – is usually steep at the beginning of a rate rise cycle.