Fee income at Rothschild, the privately owned and independent advisory firm, came in at just under $1bn (£644m) last year.
That beats those of the giants UBS, Credit Suisse and Bank of America Merrill Lynch, according to analysis by Financial News.
Rothschild's strength arguably largely derives from the fact its small size and focus means it is not tainted by conflicts of interest.
Its modus operandi also differs from its more cut-throat rivals in the amount of time people stay with the firm.
Nigel Higgins, co-chief executive, has been at the bank for 30 years, while his co-chief in Paris, Olivier Pecoux, has been there 21 years. Its chairman David de Rothschild has worked there since the mid-1960s.