Shanghai's key stock market fell the most since April 14 as financial shares and electricity producers declined.

The Shanghai Composite Index, which tracks yuan-denominated A shares and hard-currency B shares, shed 4.13 percent, or 154.36 points, to 3,579.15 at 3pm.

Losers in the Shanghai market outnumbered gainers 712 to 85 while four were unchanged.

The Shenzhen Composite Index, which tracks the smaller domestic stock exchange, was down 4.35 percent, or 48.84 points, to 1,073.81.

Industrial and Commercial Bank of China, the nation's biggest lender, lost 3.24 percent to 6.28 yuan (90 US cents). Shanghai Pudong Development Bank Co, part owned by Citigroup Inc, plunged 7.36 percent to 29.32 yuan.

ICBC, the world's largest bank by market value, will open a US$50-million unit in Dubai, adding to its emerging-market holdings in Asia and South Africa.

The bank won the "final license'' from United Arab Emirates Dubai Financial Services Authority on April 28, Beijing-based ICBC said in a statement to the Shanghai stock exchange today. The subsidiary will accept deposits, provide credit, manage assets and arrange deals in investments.

The bank now has more than 110 branches in 13 countries and regions worldwide. ICBC has also applied to open branches in New York and Australia.

Pudong bank's shares tumbled after it said 412.5 million of yuan-denominated shares will become tradable next week as a two-year lockup period expires.

Pudong Bank's two largest shareholders will be allowed to sell part of their holdings, representing 7.3 percent of total outstanding shares, from May 12, the Shanghai-based bank said in a statement to the city's stock exchange today. Pudong Bank still has 6.5 billion non-tradable shares.

Shares of Pudong Bank have dropped 22 percent this year, triggered by the collapse of China's equity market bubble and the prospect of an additional share offering that may raise as much as 20 billion yuan.