It has taken a while, but the world's biggest asset managers have woken up to the possibilities of robo-advisory.

Twelve months ago it seemed they were asleep - and while they snoozed, new players such as Wealthfront, Betterment and Nutmeg were going to gather billions of assets. Startups were being born every month, all offering variations on the same theme: automated investment advice based on analysis of a customer's lifestyle and tolerance of risk, implemented mostly through purchases of exchange-traded funds to keep costs low.