Zhong Shanshan, chairman of Nongfu Spring Company, attends the company's new product launch conference in Baishan, Jilin province, on Feb 1, 2015.  (JIANG XIN / VCG VIA GETTY IMAGES / BLOOMBERG)

It was the hottest IPO in town. Now Nongfu Spring Co’s stock surge is turning its founder into the Chinese mainland's second-richest person.

Shares of Nongfu Spring Co jumped as much as 85 percent and closed up 54 percent in Hong Kong

Shares of the bottled water maker jumped as much as 85 percent and closed up 54 percent in Hong Kong. The debut was the city’s fourth best on record among firms that raised more than US$1 billion.

The surge is pushing the net worth of Zhong Shanshan, who owns 84 percent of the firm he founded in 1996, to almost US$51 billion, according to the Bloomberg Billionaires Index. He’s now the wealthiest person on the mainland, just after Alibaba Group Holding Ltd’s Jack Ma and above Tencent Holdings Ltd’s Pony Ma.

The IPO was a smash hit in Hong Kong, so much so that the retail portion was oversubscribed by more than 1,100 times and Nongfu increased the number of shares allocated to the public. That was after it priced at the top end of a marketed range.

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Despite the coronavirus outbreak, the IPO market on the mainland and in Hong Kong has remained vibrant this year. Companies raised almost US$60 billion via new share sales in 2020, more than double from the same period in 2019, data compiled by Bloomberg show. Hong Kong is becoming an increasingly popular listing venue amid US-China tensions, while demand from retail investors has been surging as ample liquidity encouraged banks to lend. On the mainland, IPOs produced at least 24 new billionaires in the first half of the year.

READ MORE: Mainland's red-hot IPOs creating a new billionaire weekly

Zhong, also known by the local media as the Lone Wolf for eschewing business groups and politics, is the only tycoon among the mainland's five richest people who isn’t from the tech or real estate industry, which typically dominate the rankings. His fortune was boosted in April when Beijing Wantai Biological Pharmacy Enterprise Co, a company he acquired a controlling stake in almost two decades ago, went public in Shanghai. The stock has surged more than 2,150 percent since then.

Now Zhong is sharing his success: The Nongfu listing is also creating at least 68 new millionaires. Dozens of them became shareholders just last year, when Zhong and his holding company transferred 0.79 percent of Nongfu as part of a staff incentive program.

Jack Ma has topped the list of the mainland's richest people for most of the past six years, after Alibaba went public in the US. The listing of his Ant Group is poised to boost his fortune further -- his stake is worth US$25 billion at the US$225 billion valuation the payments giant is targeting.