WASHINGTON - Big banks are taking turns on the treadmill to see how well they can take a pounding.

The government began to conduct financial "stress tests" Wednesday to determine how well the biggest U.S. banks could hold up if the recession got worse. What will the federal examiners be looking for? Will the banks, which have received billions in aid under the government rescue program, get a "passing" or "failing" grade?

Q As if we don't already have enough stress from the economic meltdown: What are these "stress tests," anyway?

A Just as doctors put patients on a treadmill to check for possible heart disease, the government is looking at the financial conditions of the biggest banks -- Citigroup Inc., Bank of America Corp., Goldman Sachs Group Inc., J.P. Morgan Chase & Co., 19 in all -- to help decide whether they have sufficient capital to withstand fresh shocks to the economy over the next two years.

People with blockages near the heart may have normal test results and no symptoms at rest. So patients are put on a treadmill: Up goes the speed and extra stress on the heart can reveal signs of problems.

Economic scenarios used in bank stress tests are the equivalent of jacking up the treadmill, but to unmask financial weaknesses. Stress testing is widely used in the financial industry; federal regulators use it in their periodic "safety and soundness" reviews of banks, and banks run their own stress tests.

Q How do they work?

A The tests use computer-generated models to gauge the effect of various "stressors" on the bank's financial condition, trying out hypothetical settings of variables such as interest rates, unemployment and business conditions. As a banker, "you run a variety of future scenarios and what it means for your bank," said Wayne Abernathy, an executive vice president of the American Bankers Association.

Q How long will the stress tests take, and will banks be graded on them? What will the government do with the results?

A They're expected to be completed by the end of April. There won't be any grades.

"The outcome of the stress test is not going to be fail or pass," Federal Reserve Chairman Ben Bernanke told Congress Tuesday. "The outcome of the stress test is: How much capital does this bank need in order to meet the ... credit needs" of American borrowers to get the credit system flowing again.

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