But establishing the connection can be difficult. In the rarefied world of family money, deals between dynasties are still favoured.
The average deal size for office-to-office deals in 2013 was $119 million compared to $76 million syndicated by investment banks, according to UBS and family office data provider Campden Wealth.
"Family offices need someone they trust," Haimes said. "You need to go into each meeting without an agenda, without trying to presuppose what a client wants."
In an industry where one professional recommends "hanging round Mayfair" as a good way to find business, industry figures say investment bankers used to cold-calling with ideas need to work to establish rapport.
"You've got to find points of entry other than a pitch about the investment opportunity of the quarter," said Andrew Porter, director of research at Campden.
"Family offices are for life, I always say. If you don’t have patience, if you don't want to engage in a non-transactional way, don't bother."