The following video is part of our nationally syndicated Motley Fool Money radio show, in which host Chris Hill and advisors Ron Gross, James Early, and Joe Magyer discuss the week's business and investing news. This week's guest is Wall Street banking analyst and author Mike Mayo. In this audio clip he analyzes the challenges that Europe's debt crisis poses to U.S. financial-services firms and the one he believes is the most protected from European threats.

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