Like a patient after a near-death experience, anxious to be free of their medication but fearful of a relapse, financial markets are uncertain whether to be relieved or disappointed that the path to ‘normalisation’ has yet again been delayed by the Federal Reserve's decision to leave rates unchanged.

Inflation is the 'abnormal' vital sign for the US economy. Consumer prices fell in August and are just 0.2% higher than a year ago. Even after stripping out the effect of lower gasoline and food prices, "core" inflation is between 0.2 and 0.8 percentage points below the Fed's 2% target. Although the unemployment rate has fallen to 5.1%, the level that the Fed believes is consistent with full employment and the emergence of wage and price inflation, the Fed's Open Market Committee is not yet confident that inflation will converge to its target.