Dually listed companies' share prices in Shanghai are 33.24 percent higher than their counterparts in Hong Kong , a newly launched index showed yesterday.

Hang Seng China AH Premium Index was down 0.21 points, or 0.16 percent, to 133.24 on its debut yesterday, showing that H-share prices have narrowed the gap with A-share prices but still lag far behind. The index stands at 100 if the two prices are at par.

Special coverage: Markets Watch Related readings:  New index to track AH share price gaps  HK becomes world's 2nd largest IPO market  A plus H index to be launched soon Mainland and Hong Kong bourses track joint path for equities growth

The index was one of the four launched by Hang Seng Index Services Ltd, the index manager of Hong Kong's stock exchange.

The other three are the Hang Seng AH (A+H) Index, Hang Seng China AH (A) Index and Hang Seng China AH (H) Index. They gauge the performance of A and H shares together, and A and H share prices individually.

The three indexes all gained yesterday, thanks to a rally in Shanghai and Hong Kong. The Hang Seng AH (A+H) Index rose 73.44 points, or 3.26 percent, to 2,327.36. Hang Seng China AH (A) Index and Hang Seng China AH (H) Index grew 79.77 points and 69.75 points respectively to 2,779.77 and 2,141.4 respectively.

The indexes cover 27 companies that trade both in Shanghai and Hong Kong. The largest index constituents include China Life, Sinopec Corp, China Merchants Bank and the Industrial and Commercial Bank of China . The four constitute almost half of the index.

Shenzhen-listed A shares are yet to be included since Hang Seng Index Services Ltd has not reached any understanding with the Shenzhen bourse. But discussions are on and "the number of constituents will be raised to 29 when the Shenzhen stocks are included", said Vincent Kwan, director and general manager of Hang Seng Index Services Ltd.

Analysts hailed the launch of the indexes.

"With more mainland companies trading shares in both markets, Hong Kong investors are now paying special attention to Shanghai and Shenzhen markets," said Ricky Tam, chairman of Hong Kong Institute of Investors.