(Bloomberg) -- Private wealth will expand at a weaker pace through 2020 than previously forecast because the global economy isn't advancing as quickly as expected, according to Credit Suisse.

Wealth is now expected to expand 6.6% a year to $345 trillion through June 2020, the Zurich-based bank said in its annual wealth report on Tuesday. That compares with last year's projection of an increase of 7% a year to $369 trillion by 2019.

"The global economic outlook is weaker than previously expected," the world's fourth-largest wealth-management firm said in the report. "This leads us to revise our projections downwards."

Private wealth measured in dollars fell 4.7% to $250.1 trillion in the 12 months through June, the first decline since the 2008 financial crisis, as the greenback rose against other currencies, according to Credit Suisse. Net worth valued in dollars dropped in every region except China and North America during the period.

The Swiss bank's prediction is based on the global economy accelerating "slightly" and China's economy "stabilizing" as it continues its transition toward consumption and services.

The global economy may grow 3 % this year, compared with 3.4% in 2014, according to the median estimate of 43 economists surveyed by Bloomberg. Growth is expected to revert to 3.4% in 2016 and 2017, according to the Bloomberg survey.

SLOWER GROWTH

While wealth has doubled since 2000, including a fivefold increase in China, the pace of growth has slowed in recent years, Credit Suisse said. The richest 0.7 % of the world's population own 45.2 % of global wealth.

A stronger dollar led the number of super-rich with a net worth of more than $50 million to decline by 800 since mid-2014. The dollar climbed 8% against the pound, 17% versus the yen and 19 % versus the euro between June 2014 and June 2015, according to the report.

Credit Suisse estimates 123,800 individuals are worth more than $50 million. Half of these ultra-wealthy people live in North America, while almost a quarter reside in Europe. The number in the U.S. rose by 3,800 to 58,900 during the 12 months covered by the report, while in China the super-rich increased by 1,800 to 9,600 over the same period.

Credit Suisse observed a "small increase" in individuals worldwide owning more than $500 million, according to the report. The U.K., Germany and Switzerland complete the top five countries for the ultra-wealthy.

Wealth growth in Europe may out-pace the rate of growth in the U.S. over the next five years, although the U.S. is expected to remain the richest nation, with almost $113 trillion by 2020, compared with $85.9 trillion in 2015.

Credit Suisse sees emerging markets out-pacing higher- income countries, even after a plunge in China's stock market in June and the devaluation of the yuan triggered a sell-off across financial markets over the summer. Wealth in China will surge more than 9% a year, based on the country's economy advancing 6.2% a year, Credit Suisse forecasts.

MORE MILLIONAIRES

The number of millionaires will probably increase 4 % to 49.3 million over the next five years, with Malaysia more than doubling the number of affluent individuals with $1 million or more, Credit Suisse forecasts. Millionaires will increase at least 70% in China, Saudi Arabia, Taiwan, Colombia and Poland, according to the report.

Credit Suisse is the fourth-largest wealth manager, behind Swiss competitor UBS, Morgan Stanley and Bank of America, London-based consultancy Scorpio Partnership said in a report in July.

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