A "perfect storm" of three economic forces—impatient shareholders, unrealistic demands for growth and a slowing economy—is compelling European executives to consider a number of risky acquisitions. Focusing on building up a profitable core business is often the best path to success, but bedazzled managers too often look far afield instead.

The confluence of these three forces has disoriented many managers, causing them to overreach for fast growth, and prematurely abandon their core businesses. We find that companies in leading positions, with the most to lose, have the greatest tendency to succumb to these temptations. Call it a "paradox of success."

Mr. Zook, a director of the world-wide strategy practice for Bain & Company, is the author of "Profit from the Core" (Harvard Business School Press, March 2001). Mr. Marchal heads Bain's Paris office.