When US billionaires Bill Gates and Warren Buffett held a banquet in China a few years ago to urge fellow tycoons to donate their fortunes to charity, some of their intended targets didn’t bother to turn up.

The no-shows sparked a fierce debate on social media: are China’s super rich really so stingy?

By some measures, they are. Total charitable giving in China stands at just 4% of levels in the US or Europe, according to the United Nations Development Programme.

Chinese charities have been hit by scandal, and there is widespread mistrust of the private wealth on which much of the giving depends.

But according to a new report from Harvard University and the Swiss bank UBS, the picture is far more complex.

"Philanthropy in China today is in a state of expansion, experimentation and evolution," it said.

Donations from the top 100 philanthropists in mainland China have more than tripled between 2010 and 2016 to $4.6bn (3.6bn pounds), according to the study.

Of the 200 wealthiest people in China, 46 have foundations.

And two-thirds of the people surveyed by the study’s authors had established or were planning to establish foundations.

Wang Bing, who has been called China’s "most influential" philanthropist, says Chinese tycoons aren’t stingy, they’re just cautious.

"Everybody in my circle wants to give," he tells BBC News. "There is a lot of money available that hasn’t been donated."

"These people are smart. That’s why they’re rich. So, they’re not going to give their money to just anyone. They want to donate to charities that are effective at what they do."

Asked how many such organisations exist in China, he says "very few".

China’s top 3 philanthropists (according to the 2016 Hurun Report):

1，Pony Ma, founder of Tencent, gave $2.15bn to the Tencent Charity Foundation

Chen Yidan, co-founder Tencent, gave $615m to Wuhan College

He Qiaonu of Beijing Orient Landscape, gave $450m to various charities

Experts say the challenges to philanthropic giving are numerous, including public scepticism, a lack of transparency and shortage of experienced talent.

What is clear, according to the Harvard report, is that there is genuine innovation happening in China’s vibrant tech world.

Technology giants Tencent, Alibaba and Sina all have desktop and mobile platforms designed to encourage mass giving by the general public, as well as larger-scale donations by the wealthy.

According to one estimate, more than 23 million people in China gave charitable gifts online in 2015.

Last September, a total of 300m Chinese yuan in online donations were raised within three days.

Tencent and its partners matched that amount, giving more than $77m to thousands of charities.