The cumulative net worth of "ultra-wealthy" individuals fell in 2018, according to a report by Wealth-X.  

Also, the number of people who fall into the ultra-wealthy bracket – those with a net worth of $30 million or more – stalled, rising by just 0.8 percent in 2018, compared with 12.9 percent in 2017. 

"A late-year slump in investor sentiment and global equity markets more than offset earlier gains, contributing to a decline of 1.7 percent in the combined net worth of the ultra-wealthy," noted the World Ultra Wealth Report 2019. 

Despite the slowdown, the report predicted a return to growth both for the ultra-wealthy population – 353,550 individuals by 2023. It also expected their combined wealth to increase to $43 trillion by the same year, an additional $10.7 trillion. 

The report examined both the financial status of the ultra-wealthy and where they were located.

Reflecting the recent downgrade by Moody's credit rating agency, Hong Kong lost its status as the world's leading ultra-high-net-worth city to New York. Hong Kong's 11 percent decline in its ultra-wealthy population was due to a "slump in Asian stocks and a softening Chinese economy," according to the report.

Europe has two cities in the top 10, with London overtaking Paris in 2018. The Wealth-X research noted that London was – despite "Brexit-related weakness across the economy" – still attractive for the ultra-wealthy as there were "new opportunities for wealth creation amid the heightened uncertainty."

Germany, meanwhile, had no cities in the top 10, despite having more than 15,000 ultra-wealthy individuals. Wealth-X noted this was partly due to "the fact its significant levels of wealth are far more evenly dispersed across its major cities."

Though still a significant minority at 14.6 percent, the number of ultra-wealthy women was its highest ever recorded at 39,000. While a higher proportion of the women were aged under 50, an "indication of shifting trends in global wealth distribution, changing cultural attitudes, the rising frequency of inter-generational wealth transfers ... reveals how technology is creating new opportunities for female entrepreneurs to create wealth."