Citigroup's success at combining balance sheet strength with the investment banking skills of Schroder Salomon Smith Barney (SSSB) is raising fundamental questions for its bulge bracket competitors. The key strategic issue now facing the industry is this: will the top investment banks of the future need to be in the commercial banking business as well?

John Mack, the new CSFB chief executive, thinks so. And this is not some sudden conversion just because he has joined the Credit Suisse group. Just before he left Morgan Stanley, he told one potential recruit that the lack of commercial banking was the biggest threat facing Morgan Stanley.