Alibaba Group Chairman Jack Ma attends 2018 Alibaba Xin Philanthropy Conference on September 5, 2018. Visual China Group | Getty Images

The total wealth of global billionaires grew to $8.9 trillion in 2017, an increase of more than 19 percent from the previous year, according to a study released Friday by UBS and PwC. China's ultra-wealthy are driving that trend, the report said, adding two new billionaires per week last year, and growing at a rate almost double that of the Americas and Europe; in Asia as a whole, three people a week saw their net worth cross the $1 billion mark. "Over the past five years (2012–2017), the sum passed by deceased billionaires to beneficiaries has grown by an average of 17% each year, to reach USD 117 billion in 2017. In that year alone, 44 heirs inherited more than a billion dollars each (56% Americas, 28% EMEA, 16% APAC), totalling USD 189 billion (the discrepancy with USD 117 billion is assumed due to growth of assets in probate and revaluation of assets)," the report said. But another key demographic is growing. The number of female billionaires grew to 2,158 in 2017, up 9 percent from 1,979 in the previous year. While women still represent a small portion of the total number of billionaires overall — 11 percent — their rise could indicate a steady shift in wealth creation.

Female billionaires – one-tenth of the world's richest

Asked about the growth of female billionaires, Josef Stadler, head global ultra high-net-worth at UBS, said: "It's growing." He differentiated between the way male and female billionaires distribute their wealth. "They are the same when it comes to creating value, but different when it comes to distributing the value," Stadler told CNBC's "Squawk Box Europe" on Friday. "Women tend to foster family values and want to invest more into the sustainability area, whereas males are more value creators and leave it then to their females or to their officers and family officers or foundation officers to basically give back to society." He noted that the number of female billionaires was increasing overall, but highlighted a key cultural distinction between China and the West. "We see in China entrepreneurial female billionaires," Stadler said. "Whereas in Europe and the United States there are more females who inherit, but then get into entrepreneurial activities as a result."

In China, the total share of female billionaires stood at 8 percent last year. In comparison to the portion of billionaire women in Western Europe and the Americas, that number is lower, but represents an increase of 13 percent, higher than that of Europe and America.

Chinese billionaires up 2,200% in last dozen years