Volatility returned to global markets late last week after the European Central Bank President Mario Draghi left interest rates unchanged and downplayed the need to commit additional stimulus. The news surprised markets that had been expecting an extension of the ECB's asset purchase program. Mr. Draghi's only new announcement after again downgrading euro-area growth forecasts was that ECB officials would examine ways to ensure the current program overcomes a worsening scarcity of target bonds to buy. With the scheduled end of the 1.7 trillion-euro (US$1.9 trillion) plan just six months away, Mr. Draghi said that ECB board members have not yet discussed what they will do when the expiry date arrives by March 2017.