SHANGHAI (Bloomberg) — Willis Group Holdings Ltd., the world's third-largest insurance broker, plans to buy out its joint venture in China, where property and casualty coverage premiums rose almost 50 percent in this year's first four months.Willis "fully" intends to exercise an option to purchase the 49 percent owned by its Chinese partner in Willis Insurance Brokers Co., which dropped "Pudong" from its name, chief executive officer Joe Plumeri said in Shanghai yesterday.

London-based Willis also plans to add more branches to the venture's current network of 20 in the country, aiming to make China its most profitable business in Asia within five years.

Risk consultants such as Willis and Marsh & McLennan Cos. seek opportunities in China as the nation's companies open plants and expand overseas, boosted by an economy that's grown an average 10 percent since 2001. The insurance brokers advise companies on their risks and on appropriate insurance coverage.

Insurers in China sold 71 billion yuan of property and casualty premiums in the first four months of 2007, up 43 percent from a year earlier.

In January, bigger rival Marsh won the first wholly owned permit to broker policies for large-scale commercial risk, reinsurance, and international marine, aviation, and transport insurance in China. The licence enables the broker to operate independently, rather than through a local partner.