billionaire
/ˌbɪljəˈnɛr/
noun
A person possessing assets worth at least a billion dollars (or pounds, etc.).
Melbourne is filling with tycoons, moguls, magnates, billionaires and mere millionaires.
magnate,mogul,big businessman,baron,merchant prince,captain of industry,industrialist,financier,top executive,chief,lord,magnifico,nabob,grandee