Are American Banks strong enough?

Tier I ratio reflects how much of a financial cushion a banks has to protect it from unexpected problems.

Federal regulators require a bank to have a Tier I ratio of 4%. A bank with a ratio of 6% or higher is considered to be well capitalized.

As June 30, Bank of America's Tier I ratio was 8.5%, J.P. Morgan was 8.4% and Citigroup fell to 7.4% down from 8.6% .