The decision of Bank of America Merrill Lynch to add 2,000 to its "thundering herd" of US wealth advisers this year has raised eyebrows, as wealthy clients increasingly show preference for a more personal approach to private banking.

The hirings in US retail brokerage business will see numbers increase to around 17,000, mainly in the US. The bulk of them will be achieved by training "rookie" brokers, rather than poaching. Even so, mass hirings on this scale during so short a time period have been rare in the wealth sector.