They want you

Private banks make most of their money from their richest clients. The segment called ultra-high-net-worth (UHNW) - those with investible assets of US$10 million and above - comprise about 20 per cent of a private bank's clientele but generate 80 per cent of its revenue.

As such, banks will go to great lengths to attract and retain their biggest clients. For example, they might provide access to niche investments that otherwise only hedge funds or specialist funds would see.

They provide support to execute complex trading ideas (acting like a prime broker might work for a hedge fund) and would offer all of this at discounted fees.

To get a sense of what institutions actually do we approached a number of international private banks to see what services they offered their richest customers.

Private banks that are part of a larger entity encompassing an investment bank are able to treat rich clients as a quasi-institution. If the client wants to do heavily structured trades, involving leverage, collateral, derivatives, exotic markets and the like, they can call on the bank to treat them as if they're a mini-hedge fund, bringing in resources from the brokerage and investment banking units to execute such transactions.

This relationship is more natural if the client is a family office, a professional office dedicated to managing family wealth and investments - effectively, an institution.