Super-rich families are threatening to take away business from private banks and manage some of their trillions of dollars of assets in-house.

Almost $29 trillion (€24 trillion) of assets are owned by high net worth individuals and wealthy families, according to estimates made last year by Capgemini, the consultant, and Merrill Lynch, taking $1m as the lower threshold. They said they expected this to grow to more than $40 trillion in three years' time. At least $2 trillion is owned by 70,000 individuals and families owning $30m or more.