As the economy strengthens, industry leadership is more contestable and fleeting than ever. Globalization, changes in technology, and deregulation not only drive strong supply-side growth in the broader economy but also create new sources of supply, new competitors, a flood of new innovations (and knockoffs), and dramatically higher productivity. Today’s industry leaders will face increasing risk as growth emboldens attackers—many of whom will have lower costs, lower return requirements, or both.

A version of this article appeared in the March 2005 issue of Harvard Business Review.