BEIJING — China's creation of a company to invest part of its $1 trillion in foreign currency reserves will have no impact on Beijing's substantial holdings of dollar-denominated assets, Premier Wen Jiabao said yesterday.

Speaking at a news conference, Wen also said Beijing must improve stock market supervision and build a mature financial system. His comments came two weeks after a plunge in Chinese stocks triggered a global selloff, but Wen did not mention that market turmoil.

Wen's comments reflected China's efforts to harness its 10 percent-plus annual economic growth more effectively and reassure the world about its intentions.

The government said last week it is creating a company to make more profitable use of its reserves, up to 70 percent of which are believed to be held in safe but low-return U.S. Treasuries and other dollar-denominated assets. Some economists suggested that could affect Beijing's purchases of Treasuries, which helps to finance the U.S. government budget deficit.

"It is true that in China's foreign exchange reserves, U.S. dollar-denominated assets account for a large proportion," Wen said. "I can assure you that by instituting such a foreign exchange company, it will not have an impact on the U.S. dollar-denominated assets."

Wen did not respond directly when asked how the company will make investments or give any other details.

China's reserves have surged as surging exports bring in a flood of foreign currency, forcing the central bank to drain billions of dollars a month from the economy by selling bonds in order to reduce pressure for prices to rise. The reserves are growing by about $20 billion a month.

"How to properly use such a huge amount of foreign reserves has become a new problem facing us," Wen said.

Wen also stressed Beijing's desire to develop Chinese financial markets as a tool to finance growth.

"Our goal is to build a mature capital market," he said.

The government must improve the quality of publicly traded companies, make the market "open, fair and transparent" and improve oversight, the premier said.

"We also need to encourage and do a good job in the timely disclosure of information in the stock market," Wen said.

China's stock markets have grown rapidly in recent years, but are subject to wild swings in prices and accusations of insider trading and other abuses. Most traded companies are government-owned, and economists say the market's performance has little connection to the overall health of the Chinese economy.

The premier didn't mention the turmoil of Feb. 27, when a 9 percent drop in the Shanghai stock index set off shock waves that dragged down markets in New York, Hong Kong, London and elsewhere.

Wen's comments are part of a long-running effort by Beijing to reassure both financial markets and the Chinese public that it has social and economic problems under control, said Robert Broadfoot, managing director of the consulting firm Political and Economic Risk Consultancy Ltd.

Despite its rising wealth, China faces a litany of challenges: rural poverty, widespread official corruption, uncompetitive banks, and potentially huge costs for pensions and social programs for an aging population.