Revealed: rich set to get even richer

The number of millionaires will soar by more than 70 per cent over the next decade, and the members of this elite club will control more than $200 trillion (£121trn) in assets, twice as much as they do now, according to the consulting firm Deloitte – another piece of evidence that the world's rich will continue to get richer.

The study, aimed at encouraging investment by banks in wealth management services for the super-rich, also concluded that China will enter the top 10 countries with the most millionaires.

However, the dominance of the US – where eight of the world's 20 richest men, including Bill Gates and Warren Buffett, currently live – and the rest of the developed world will continue, Deloitte says. It predicts there will be 20.6 million millionaire households in the US in 2020, up from 10.5 million now, controlling $87.1trn of assets. The number of UK millionaires is set to grow from 2.9 million to 3.8 million at the start of the next decade – keeping the country in fourth position.

"Which countries may offer the most promising future and how wealth managers can potentially increase profitability in the next decade are important questions for a wide range of financial institutions," said Andrew Freeman, the executive director of the Deloitte Center for Financial Services. "Identifying and understanding how different market segments are changing can help formulate growth strategies."

Hong Kong is likely to have the highest density of millionaires in 2020, with 47 per cent of the population holding more than $1m, followed by Singapore with 37 per cent and Switzerland on 24 per cent. The study, conducted with Oxford Economics, defined wealth as financial assets, such as stocks and bonds, and non-financial assets including primary residence.