Three new chapters will be added into the Hong Kong stock exchange's initial public offering rules, while double-digit companies are expected to apply to be the first listings under the new rule beginning Monday, the head of Hong Kong Exchanges and Clearing (HKEx) said on Tuesday.

According to the new rule, firms with dual-class shareholding structures, biotechnology companies without revenue yet and those already listed out of the city will be able to apply for the listing in the city. 

HKEx's chief executive Charles Li Xiaojia said the first listings under the new rule would float shares in late June or early July.

"There is a large number of companies that have indicated to us that they are ready to file," said Li. "I think they are just waiting for the rules to be published today.

"I don't want to speculate on the numbers, but I do think we are talking about not single numbers, or single digit numbers. We are talking about numbers that are potentially going into the dozen. Hopefully before the summer, we will see at least a number of companies be able to have access to the market."

"In terms of number, I believe more companies will list under the biotech chapter. But the scale of applicants with double-class shareholding structure will be larger," he added.

The new listing rule comes after a Chinese Depository Receipt (CDR) mechanism was released on the Chinese mainland last month as part of efforts to further open up the capital market, encouraging firms to be back in the mainland's A-share. But Li was confident in Hong Kong, as he believed the mechanism was not for competition with Hong Kong.

The exchange received 283 responses to the consultation, most of which supported the proposals, while several amendments were made to the proposed rules.

According to the result of the consultation into reform of the bourse's listing rules, the exchange proposed applicants for listing under the biotechnology chapter must have a minimum expected market capitalization of HK$1.5 billion at the time of listing.

For companies with dual-class shareholding structure, the corporate governance committee is required to be made up entirely of independent non-executive directors.

In addition, applicants under the secondary listing chapter need to be listed on a qualifying exchange, including the NYSE, Nasdaq and LSE's main market for at least two financial years, with an expected market capitalization of at least HK$10 billion.