Hong Kong Exchanges and Clearing Ltd Chairman Chow Chung-kong (L) and Hong Kong Chief Executive Leung Chun-ying pose before hitting a gong during the launch ceremony of the Shanghai-Hong Kong Stock Connect in Hong Kong Nov 17, 2014. [Photo / Agencies]

SHANGHAI - A landmark stock trading link program allowing Hong Kong and Shanghai investors to buy and sell shares on each other's bourse is officially launched on Monday, marking the start of one of China's most significant moves to further open its capital markets.

Despite the A-share buying reaching the program’s daily limit of 13 billion yuan ($2.1 billion), the benchmark Shanghai Composite Index closed at 2,474.01 on Monday, down 0.19 percent.

Hong Kong stocks slid 1.2 percent to 23,797.1 in the first day of the stock connect, with mainland investors net buying 1.77 billion yuan Hong Kong shares out of their 10.5 billion yuan quota.

The Shenzhen Component Index on Monday closed at 8,361.21, down 0.52 percent.

The market performance was in part dragged by the share price decline within financial sector, whose upside sentiment from the trade link was previously priced in, said analysts.

The Shanghai-Hong Kong Stock Connect is the primary vehicle for China to take the next step to opening up its capital market to the rest of the world and is a positive move for the long term, said Mark Matthews, head of Asia research at Bank Julius Baer &Co, which oversees about $286 billion, said to Bloomberg.

Hong Kong's Chief Executive Leung Chun-ying welcomed the launch of the pilot program to provide mutual trading access between the Shanghai and Hong Kong stock markets.

Leung said the program will increase the competitiveness of both stock markets and enhance Hong Kong's status as a major offshore renminbi trading hub.

"It is a breakthrough in the opening up of China's financial markets and an important milestone in the development of Hong Kong as a unique gateway between the mainland and international investors," Chairman of the Hong Kong Exchanges and Clearing Limited Chow Chung-kong said at the launching ceremony.

On the Southbound link, institutional investors and individuals with over 500,000 yuan ($81,421) in their brokerage accounts may trade Hong Kong shares through a broker on the Shanghai stock market; while heading Northbound, Hong Kong investors and international investors with Hong Kong brokerage accounts may trade shares listed on the Shanghai stock market.

There are 568 eligible stocks for Northbound trading, namely constituent stocks of the Shanghai Stock Exchange 180 Index and SSE 380 Index as well as shares that are dual listed in the two bourses (A+H shares). For Southbound, investors will be able to trade 268 eligible stocks, namely constituent stocks of the Hang Seng Composite LargeCap Index and Hang Seng Composite MidCap Index as well as shares that are dual listed in the two bourses (A+H shares).