New York and London are ranked the top two global cities according to economic advisory firm Oxford Economics in its inaugural Global Cities Index. This index is described as a “comprehensive evaluation of the world’s 1,000 largest urban economies.”

Tokyo, ranking fourth, is Asia's top urban economy, followed by Seoul at 41st and Singapore at 42nd. Korea’s second-largest city, Busan, came in at 252nd.

The index was compiled using five broad categories — economics, human capital, quality of life, environment and governance — with the most weighted emphasis on economic factors such as wealth generation and employment opportunities.

By category, New York leads in the economics category due to the size of its economy, as well as its structure and growth. London excels in human capital with its level of educational attainment, universities and corporate headquarters.

Seoul ranks 5th in human capital, with its level of collective knowledge and skills, corporate presence and demographics. Preceding Seoul in the human capital category are London, Tokyo, Riyadh and New York, respectively.