An industry with low exit barriers is more attractive because it allows under performing firms to exit more easily. This in turn reduces competitive pressure on the remaining firms because excess capacity is removed. In contrast, an industry with high exit barriers reduces its profit potential because excess capacity still remains. All of the large airlines featured in Strategy Highlight 3.2 (American, Delta, and United) have filed for bankruptcy at one point or another. Due to a unique feature of U.S. Chapter 11 bankruptcy law, however, companies may continue to operate and reorganize while being temporarily shielded from their creditors and other obligations until renegotiated. This implies that excess capacity is not removed from the industry, and by putting pressure on prices further reduces industry profit potential.