For this reason, ad hoc responses will still be critical, such as last week's federal guarantees for money-market funds, Fed loans to banks to buy asset-backed commercial paper and, on Sunday, approval of the remaining two big independent investment banks, Morgan Stanley and Goldman Sachs, to become Fed-regulated bank holding-companies whose investment bank units can now borrow from the Fed on the same terms as other banks.

ECONOMIST: The financial crisis

Additionally, members of bank holding companies that have broker dealers cannot serve as so-called public representatives.

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We only assessed the 20 largest bank holding companies in terms of total assets, as of December 2012, according to the National Information Center, a repository of financial data and institution characteristics collected by the Federal Reserve System.

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