Bank stress tests to clarify U.S. credit crisis

The results are expected to show that the 19 banks must raise possibly $150 billion or more in fresh capital, with investors expected to punish stocks of the neediest banks.

"Most banks will have to raise capital in some form," said FBR Capital Markets managing director Paul Miller. "The capital raises will be much bigger than people think."

Uncertainty about what the tests might reveal had made banks stocks "uninvestable" at this point, he added. "You just don't know how the government is going to view it."

Public release of the stress test results is set for Thursday, a government official said. A source told Reuters U.S. officials plan to brief the banks themselves on Tuesday.

The stress tests have transfixed markets for weeks, shaping a suspenseful episode in the ongoing financial crisis that has worsened the U.S. recession and shaken economies worldwide, burdening the newly arrived Obama administration and Congress.