The Chinese mainland is poised to overtake Japan this year as the economy with the world's second-largest number of dollar millionaire households, behind the United States.

And the Asia-Pacific region will surpass North America in four years as the world's wealthiest region, according to a report by the Boston Consulting Group.

In its annual study of the world's wealth management industry, the global management consulting firm said worldwide wealth grew faster last year than in the previous two years.