Sydney has been ranked as the world's tenth largest international finance centre, according to a new study.London tops the rankings, followed by New York, Zurich, Frankfurt, Paris, Toronto, Tokyo, Amsterdam, and Hong Kong.Below Sydney are Stockholm, Milan, Brussels, Singapore, Munich and Melbourne (ranked 16th).The study, "International Competitiveness of Australia's Financial Services Sector", was commissioned by the Centre for International Finance and Regulation and conducted by academics from Sydney University and Oxford University.The rankings were based on investment banking fees billed from cross-border deals, including equity, debt, syndicated loans and mergers and acquisitions.The authors, Eric Knight, a senior lecturer at the University of Sydney Business School, and Dariusz Wojcik, professor of economic geography at Oxford, said this measure is a proxy for wider economic performance."Cross-border investment banking fees are an indicator of deal-making within the real economy," the authors said.They said they could get comprehensive data worldwide going back 15 years, which was not possible for retail banking or asset management transactions.The authors wanted to avoid qualitative rankings based on questionnaires.They said that for Sydney to improve its ranking all levels of government would need to support competition measures in the non-finance sector of the economy.They said flexible cross-border labour flow was crucial.Other drivers included population size, the presence of top universities, the presence of a stock exchange and strong rule of law (so that contracts could be enforced, for example).