If the answer was convincing, it would give me confidence in the company's portfolio. A nonanswer would lead me to suspect sloppy underwriting as the reason for fast growth. Truth be told, I worried that I had left myself open to a long-winded discussion of the power of the American Express brand, a fair argument but not new information. To my surprise, the executive paused, took a deep breath, and responded, "We keep asking ourselves that very question."

Sometimes a well-designed question hits the motherlode. Indeed, credit quality was about to become a serious problem for the company.

Kenneth A. Posner is a financial services industry analyst and a fifteen-year veteran of Morgan Stanley, where he served as managing director and senior research analyst and where his work received high rankings from Institutional Investor and Greenwich Associates. He earned his MBA from the University of Chicago, Graduate School of Business and holds the Certified Public Accountant, Chartered Financial Analyst, and Financial Risk Manager designations.

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