Hong Kong’s biotech stocks rose on Wednesday.

CANbridge rose 29%; Ab&B Bio-Tech rose 26%; Abbisko soared 7%; WuXi XDC rose 6%; Asymchem, JOINN rose 5%.

Ab&B Bio-Tech soared 158% in its trading debut in Hong Kong on Monday, after retail investors flocked to the Chinese vaccine maker’s initial public offering.

The share sale’s success builds on the rally of health-care stocks, which have been the best performers on the Hang Seng Composite Index this year. Ab&B, which sells an influenza vaccine, was so sought after among retail investors that they applied for more than $20 billion worth of margin loans to bid for the stock. That’s thousands of times the number of shares available to them.

“The strong demand, especially for sub-$1 billion deals, suggests growing comfort with risk in the biotech space,” said Gary Tan, portfolio manager at Allspring Global Investments. But it may also “indicate short-term overheating,” Tan said.

Ab&B is also the last company to go public in Hong Kong under listing rules that allowed retail investors to grab as much as half of all allocated shares in an oversubscribed new listing under the so-called clawback mechanism. Starting this August, mom-and-pop investors will only be able to get up to a 35% allocation in oversubscribed deals that trigger the mechanism.

Aside from flu shots, Ab&B is also developing vaccines for rabies, herpes and other respiratory diseases, with plans to commercialize them in China and beyond.