Last rites called for B shares

China's B shares are back in the headlines. The B-share indices in Shanghai and Shenzhen have soared to record highs in the past month on the back of growing speculation about market reforms. The rumour mill contends that China's B-share markets will be opened to mainlanders, through joint-venture mutual funds; A-share and B-share markets will merge; and the Shanghai and Shenzhen stock exchanges are set to combine. But some fund managers believe B shares' days are numbered.