All of the combined profits that major banks earned in recent years have vanished. Since mid-2007, when the credit crisis erupted, the country's nine largest banks have written down the value of their troubled assets by a combined $323 billion. The problems that began with home mortgages, analysts say, are migrating to auto, credit card and commercial real estate loans. The deepening red ink underscores a crucial question about the government's plan: Will lenders deploy their new-found capital quickly, as the Treasury hopes, and unlock the flow of credit through the economy? Or will they hoard the money to protect themselves? John A. Thain, the chief executive of Merrill Lynch, said on Thursday that banks were unlikely to act swiftly. We will have the opportunity to redeploy that," Mr. Thain said of the new capital. "But at least for the next quarter, it's just going to be a cushion." For every dollar the banks earned during the industry's most prosperous years, they have now wiped out $1.06. [Treasury Secretary Henry M.] Paulson unveiled plans to provide $125 billion to nine banks on terms that were more favorable than they would have received in the marketplace. The government, however, has offered no written requirements about how or when the banks must use the money. "There is no express statutory requirement that says you must make this amount of loans," said John C. Dugan, the comptroller of the currency. The banks could use the money from the government for any number of things. Some analysts say the banks may use it to acquire weaker competitors. Others say they might use it to avoid painful cost-cutting. And still others say the banks may sit on the capital.