The preparation work for the Shanghai-HK Stock Connect, also known as a "through train", is in the last stages, said an official quoted by Securities Daily Thursday.

According to Secretary for Hong Kong Financial Services and the Treasure Bureau K.C.Chan, the launch date of the "through train" won't be announced until both sides decide on it.

Securities Daily reports Chan saying that people had concerns on whether the stock connect would be delayed, and that he understood their concerns.

According to the report, 97 security companies in Hong Kong are qualified to engage in trading on the Shanghai-HK Stock Connect, and their stock trading volume take up 80 percent of the purchases on the Hong Kong stock market.

The Shanghai-Hong Kong Stock Connect was announced by Chinese Premier Li Keqiang in April. The plan will allow international investors, institutional and retail to trade Shanghai-listed stocks via Hong Kong's Exchange while Hong Kong H shares will be eligible for trading to Chinese mainland investors.

Prior to the program, a direct access to A shares is only limited to mainland investors and qualified foreign institutional investors with authorized quota.

Four-party agreement signed for Shanghai-HK stock connect	Top 10 trading partners of the Chinese mainland