The Gross Domestic Product of Los Angeles is third to only Tokyo and New York - and well above both London and Paris.
London is moving up the league of the world's richest cities, although it remains behind Tokyo and New York at the top of the wealth list, a new study said Wednesday.
Fast-growing cities in emerging markets are also making their presence felt on the global wealth stage, according to the research paper on UK Economic Outlook by consultants PricewaterhouseCoopers (PCW).
In 2005 London, where vast City bonuses are once again fueling property markets and other conspicuous spending, was sixth place in terms of Gross Domestic Product using purchasing power parities (PPP), according to the study.
But by 2020 it will be in fourth place, overtaking Paris and Chicago -- and while Tokyo, New York and Los Angeles will remain above it, "Londons economy is projected to grow faster than any of these cities, driven in particular by strong growth in business and financial services," said the research.
"It seems likely that the most successful cities of the future will be those that have comparative advantages in intangible business, financial and consumer services that are not so easily emulated by the rising stars of China, India or Brazil," said PCW head of macroeconomics John Hawksworth.
"London and Frankfurt should benefit from the increased financial services trade and Paris and Milan should find new markets for their fashion industries," he added.
According to the study, Tokyo topped the list in 2005 with a GDP using PPP of 1.2 trillion US dollars, followed by New York on 1.1 trillion. Los Angeles was on 639 billion, Chicago and Paris 460 billion and London 452 billion.
In 2020 the Japanese capital will have increased to 1.6 billion, followed by New York on 1.56 billion, Los Angeles on 886 million and London 708 million US dollars.
One striking detail of the projected 2020 rich list is that none of the top 30 fastest-growing large cities will be from the major advanced economies, with emerging economy cities rising up the rankings.
Five emerging economy cities are currently in the top 30 -- Mexico City, Buenos Aires, Sao Paolo, Moscow and Rio de Janeiro -- and will be joined in 2020 by Shanghai, Mumbai, Istanbul and Beijing.
The PCW study is believed to be the first of its kind covering the world's biggest 100 cities in terms of GDP while taking into account both population and average per capita income levels.