Rupert Hoogewerf looks pale and a little fragile after what he says was a busy night socialising. But as a man who makes it his business to know what people are worth - the British accountant has compiled a list of the mainland's wealthiest people for years - the schmoozing is par for the course. Hoogewerf (pronounced Hoojwerf), who was in Beijing recently to attend a private banking conference, says the event made him think about which businesses would profit most from the growing number of millionaires in China. 'Who is going to really make money out of these people?' he asks rhetorically. 'Cartier? Well, they'll sell a few watches. Armani, Zegna? Yes, they'll make something. No, the people who are really going to make money are the [international] private bankers.' His Chinese name, Hurun, has become household currency as a result of his Hurun Rich List. He first put together an annual list of the mainland's wealthiest people in 1999 in collaboration Forbes, but their alliance ended after four years when the magazine dropped him to compile its own rankings. However, Hoogewerf's now independently issued list is still widely anticipated, offering a glimpse of the mainland's super rich, who enjoy more anonymity than those in the west. He was inspired to start the rich list because he wanted to reveal a unique aspect of rapidly changing China, he says. What could he say that journalists weren't saying or tourists seeing for themselves on the streets? The answer was to focus on private wealth, a tradition that runs in his British-Luxembourgian family. And it's not their wealth but their stories that fascinate him, says Hoogewerf, who studied Chinese and Japanese at Durham University and arrived in the mainland 14 years ago to work for Arthur Andersen. What's remarkable about the mainland's swelling ranks of super rich is that so many are self-made tycoons. They include Peng Xiaofeng of LDK Solar, who is ranked No6 on his list with personal wealth of US$5.3 billion, and Robin Li Yanhong of Baidu, who is ranked 29th with US$2.4 billion. And their average age is just 47 compared to the global average of 62 estimated by Forbes. 'The stories of these people tell the story of modern China,' says Hoogewerf. The rich used to shun Hoogewerf, fearing that inclusion on his list would bring unwanted attention from regulators, tax inspectors, or party ideologues - after all, 16 of 50 on a 2003 list of people with the most capital were arrested. That's changing. Now the wealthy attend his Private Dinners series, held in major cities each summer, and he regularly flies around the country calling on people and making contacts. Sometimes, businessmen even enjoy a little bragging, Hoogewerf says, recalling how one tycoon approached him at a party and said: 'I've just bought another listed company. But I'm not going to tell you which one.' Three decades after the Communist Party announced in 1978 that 'to get rich is glorious', Hoogewerf says China's wealthy are at a unique juncture. They're not millionaires any more - they're US-dollar billionaires. 'When we look back in 20 years I think we will see 2007 as the year China's wealthy really came of age,' he says. The Rich List this year logged 106 billionaires - a figure that Hoogewerf point outs registers only those people with personal assets that they can ascertain. There may be as many as 250 US-dollar billionaires on the mainland, double the official figure. By that reckoning, China is fast catching up with the US, which has 371 this year, according to Forbes. 'Take our list as an 'at least' figure,' Hoogewerf says. 'Someone we identify with US$200 million might well be worth a billion.' He estimates there are 'a handful' of anonymous billionaires or, at least, multimillionaires in Beijing alone, usually children of senior political figures. Elsewhere, there are more self-made moguls, especially in eastern provinces. Zhejiang has the biggest number of wealthy people, with Guangdong in second place. There is some dispute over Hoogewerf's calculations - Forbes only lists 20 US-dollar billionaires from the mainland this year - but with assets often hidden from scrutiny, estimates of the rich is a perennial challenge. 'Last year saw the biggest increase in wealth here that I've ever seen,' he says. '[Since 2004] we've basically seen the number of US-dollar billionaires go from one to seven to 16 to - oh, my God - 106. I had no idea there were going to be so many.' The sudden leap is due to Shanghai's booming stock market, whose value has jumped from about 1,000 to 5,000 points in 30 months. And despite the volatility, he expects the number of billionaires to rise to 180 by next year. Like the people he researches, Hoogewerf is private, apparently reluctant to discuss his personal life. His family has strong ties to Luxembourg, where he was born and where the family's tax firm Hoogewerf & Co has its headquarters. Hoogewerf speaks six languages, including Luxembourgeois, and lives in Shanghai with his wife and two children, aged two and four. And with children at home, home life is busy, he says. That may have sensitised him to the startling finding that six of the world's richest self-made women are Chinese. They include Zhang Yin of Nine Dragons Paper, who is ranked No2, with US$10 billion; Zhang Xin of Soho China, in 16th place with US$3.6 billion; and Chen Lihua of Fu Wah International, in 25th position with US$2.7 billion. He suggests one reason for the trend is that families often divide responsibilities, with the husband working his way up the hierarchy in a stable, state-owned enterprise, while the wife takes risks in a private venture. Another reason for the women's success is that they're frequently able to hand their children to parents to raise, allowing them to resume busy careers after having a child. Hoogewerf isn't sure how long he will keep compiling the list with his Hurun Report monthly magazine team in Shanghai. He doesn't plan to settle permanently on the mainland, 'but I will always work with China', he says.