Despite a denial from securities regulators, rumours that China may merge its foreign-currency B shares into A share sharply drove up the B shares market yesterday.

The Shanghai B shares index jumped 9.12 per cent to close at 77.617. The Shenzhen B shares index surged 7.55 per cent, bringing its gain for the year to 23 per cent.

The Shanghai and Shenzhen A-share indexes also rose 2 per cent yesterday.

Some analysts believe that the index climbed on speculation of a merger that would benefit holders of B shares, which usually trade at a discount to local-currency stock.

"That the B shares may be merged into A shares is a main reason for the index to rise," said Dong Chen, an analyst with China Securities.

Bloomberg News has reported that the Shanghai Stock Exchange wants to start trials for converting foreign-currency B shares into yuan stock.

Zhou Qinye, executive vice-president with Shanghai Stock Exchange, said that the exchange would hopefully start a trial program for some B-share companies this year, according to the news agency.

"Companies may be allowed to buy back B shares or swap them for local currency A shares," Zhou said.

However, exchange spokesman Chen Ji later denied that the exchange would start any trial program.

"Zhou was misunderstood by the media," Chen said.

Dai Biao, spokesman with the CSRC also denied that the CSRC has ever planed the merger issue.

Zuo Xiaolei, chief economist with Yinhe Securities did not believe the merger would happen, either.

"There is obviously not the right time for the A and B shares to merge. As we all know, the reforms on the A share is ongoing and comes to a critical period. The government is focused on shifting all the non-tradable A shares into tradable ones. Surely they have no strength to take care of B shares," Zuo told China Daily.

"Besides, to merge B shares with A shares, regulators may first solve a lot of technical problems and build a series of new rules. These cannot be completed in a short time."

Zuo contributes the rise of the B shares index to investors wanting to obtain margin earning between the price of A shares and B shares.

B shares, introduced in the early 1990s as a means for companies to raise hard currency from foreign investors, have lost relevance as China loosens capital controls and opens its much larger yuan share market to overseas institutions.

Trading in Shanghai-listed B shares was less than a quarter of 1 percent of the volume for local-currency stocks last year.

Source: China Daily