The central bank set up Central Huijin in 2003 to bail out the country’s banks after a surge in losses on loans issued to politically connected, state-owned enterprises in the mid-1990s.

Central Huijin was transferred in 2007 to the China Investment Corporation, which had been set up to invest part of the country’s foreign exchange reserves in the stock market. The move was controversial, in part because it involved issuance of bonds to compensate the central bank for the transfer. China Investment promised that it would collect enough dividends from the banks to make payments on the bonds.

As a result of that promise, the big Chinese banks have been paying out roughly half of their earnings in dividends since then, compared with only 10 to 12 percent for many industrial companies. That has slowed the banks’ ability to comply with regulators’ demands to build capital reserves.

The high dividend payouts, in conflict with the need to raise capital, have started to prompt grumbling by Chinese bank executives. Xiang Junbo, the chairman of the Agricultural Bank of China, was quoted in July by The Study Times, a weekly publication controlled by the Communist Party School, as saying that the country’s big banks “should avoid high levels of dividend payments while we are frequently going to the market for fund-raising exercises.”

But Lou Jiwei, the chairman of the China Investment Corporation, has said that Central Huijin needs 300 million renminbi a day, or $47 million, just to pay the interest on the bonds issued to compensate the central bank. Central Huijin cannot easily sell its shares in the banks to raise money for servicing that debt, because this would increase the number of shares in public circulation and could further depress the stock prices.

The announcements by the big four banks reversed a slide in their share prices earlier in the day. They posted small gains by the close, except for China Construction Bank; it fell 0.21 percent on the day, closing at 4.83 Hong Kong dollars, but was up from earlier lows.

Another worry for the banks lies in their exposure to special borrowing units of local governments. China’s National Audit Office said at the end of June that those loans — mainly for infrastructure projects that helped China spend its way out of the global economic downturn — had totaled 10.7 trillion renminbi, or $1.7 trillion, by the end of 2010.

The debt burden from those loans is putting heavy pressure on local governments to raise the fees for water, sewage and other municipal services that were greatly improved with the loans, but which continue to be provided to the public for less than their cost, Mr. Lardy, of the Peterson Institute, said.