"A 70 per cent oil decline in the stress test would equate to oil prices at just over $10 oil per barrel and that is probably as low as the Fed would go," he said.
"The incremental stress to moving oil below $10 per barrel in a stress test would be pretty small in our view. However, banks should be worried that the price declines across all asset classes could increase from the prior stress test as a result of the steep decline in oil prices."
Banks are also tested in their ability to withstand falls in a range of other asset types including house prices, stock markets and other commodities.
Mr Goldberg said that while low oil prices put pressure on some banks, there was no reason to believe banks were going to make overall losses. "It's the fact that they have 28 negative things hitting you at once that makes them challenging," said Mr Goldberg.
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Until now, the tests have assumed that banks keep paying dividends throughout that nine-quarter period of stress — an assumption that some banks have said is unrealistic
For the past five years, the Fed has subjected banks with at least $50bn in assets to an annual two-part test designed to ensure they could keep trading through a deep recession and a big shock to the financial system.
Until now, the tests have assumed that banks keep paying dividends throughout that nine-quarter period of stress — an assumption that some banks have said is unrealistic, and should be changed in future.
Every part of every bank's book — the trading portfolio, the available-for-sale portfolio, the investment portfolio — goes through the same drill. This year no US bank failed the quantitative part of the test, which sets a minimum 5 per cent threshold for so-called "tier one" common equity, considered the safest kind of capital.
No bank had its dividend and buyback plans rejected after the qualitative assessment, which judges whether banks have a strong enough grip on their capital-planning processes.