Tourists walk next to Victoria Harbour in the Tsim Sha Tsui district as Two International Finance Centre (IFC), center, and other commercial buildings stand in the background on Hong Kong island in Hong Kong, Oct 21, 2014. (BRENT LEWIN / BLOOMBERG)

HONG KONG - Hong Kong Exchanges and Clearing Limited (HKEX) on Friday announced specific plans to expand the Stock Connect, a landmark mutual market access program connecting Hong Kong and mainland equity markets.

Mainland investors will be able to buy shares of some Hong Kong-listed biotech companies expectedly from the end of this year

The expansion will allow Hong Kong investors to buy some stocks traded in the Sci-Tech Innovation Board of the Shanghai exchange, commonly known as the STAR market, as early as 2021, according to the HKEX statement.

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Mainland investors will also be able to buy shares of some Hong Kong-listed biotech companies expectedly from the end of this year.

STAR market-listed shares that are constituent stocks of the SSE 180 Index and SSE 380 Index, or have H-share counterparts listed in Hong Kong, will be eligible for northbound trading, according to agreements of three exchanges in Shanghai, Shenzhen and Hong Kong. Accordingly, their corresponding H-shares will be included in southbound trading.

Shares of pre-revenue biotech companies listed under Chapter 18A of Hong Kong's Main Board Listing Rules that are eligible constituent stocks of the Hang Seng Composite Index, or have corresponding A-shares listed on Shanghai or Shenzhen exchanges, will be included in southbound trading.

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Shares of biotech companies that are H-shares in STAR market-listed A+H companies will be included in southbound trading.