Bank of China is negotiating for four foreign partners to take significant stakes in its business, an unusual arrangement that could mitigate the investors' risk and give the Chinese bank access to a wide range of financial know-how.

Investors that are negotiating with the Chinese bank include Britain's Royal Bank of Scotland Group PLC, the world's sixth-biggest bank by market capitalization and parent of Citizens Financial Corp. in the United States; Temasek Holdings Ltd., an investment company owned by Singapore's government; Asian Development Bank, a Manila-based development bank; and Zurich bank UBS AG, according to a person familiar with the negotiations.

Spokesmen for Royal Bank of Scotland, Temasek and the ADB declined to comment. UBS in June confirmed that it was in talks for a $500 million stake in Bank of China.

The foreign financial institutions are bidding for access to a potentially huge market and an unusual prize. Bank of China is the mainland's leading foreign exchange bank, conducting most currency trading for the central bank and other state agencies. In addition, Bank of China has a higher international profile than any other Chinese financial institution, with offices around the world and a Hong Kong subsidiary that is listed in that city.

China's red-hot economy and burgeoning consumerism have prompted a range of banks to invest in the country's financial-services sector, which is opening up under pledges made to the World Trade Organization. Under terms of the deal with the WTO, foreign banks will get unrestricted access to China's corporate lending and consumer banking market, starting at the end of next year.

Chinese banks are seeking foreign strategic investors to help them upgrade their technology, including risk-management systems, and to pass on management expertise.

The deals Bank of China is negotiating would represent a sharp departure from other Chinese banking joint ventures, including HSBC Holdings PLC's landmark purchase last year of a 19.9 percent stake in Bank of Communications.

Both Royal Bank of Scotland and UBS likely are trying to carve out joint venture businesses with Bank of China in return for their investments, banking analysts say. For UBS, wealth management and corporate finance would be an obvious fit; Royal Bank of Scotland may well bring its retail-banking experience to the table, including expertise in the hot mortgage industry.

Banking-industry analysts say they think Temasek and the Asian Development Bank would be mainly passive investors.

Royal Bank of Scotland's proposed investment in Bank of China would be a departure from its traditional focus on mature markets and controlling stakes. The Edinburgh-based lender has little presence in Asia, and a Bank of China stake could give it broader access to the fast-growing Asian market -- and bring its retail-banking experience to bear on Bank of China's vast branch network.

Royal Bank of Scotland has been punished by its shareholders over its reported interest in China. Since news of its proposed $2.5 billion investment in Bank of China came out during late July, Royal Bank of Scotland's stock has lost about 5 percent. Royal Bank of Scotland chief executive Fred A. Goodwin told analysts Friday that the bank hasn't ruled out any options in China, describing the bank's appetite for a "minority investment in anything" as "extremely limited."

Temasek, a private equity-like investment company owned by the Singaporean government, brings a reputation as a savvy and long-term investor.

Aside from its long experience as the biggest shareholder in DBS Bank in Singapore, Temasek has amassed minority positions in other financial institutions across Asia.

Swiss bank UBS already has a relationship with Bank of China, having acted as an underwriter for the initial public offering of the bank's Hong Kong subsidiary in 2002.

UBS also helped Bank of China sell an additional stake in its Hong Kong affiliate the following year. UBS continues to act as an adviser to the Chinese lender, and it is one of the firms competing to underwrite Bank of China's coming initial public offering, estimated at $3 billion to $4 billion.

Kissel reported from Hong Kong and Browne reported from Beijing. Sarah Spikes in London also contributed to this report.