Previous research has shown that firms react differently to the same institutional configurations due to their different backgrounds. This study examines a regional economy in France in which 300 firms are operating under the same framework conditions and have done so over a long period. From observations we argue that even when all previously respected factors and backgrounds are identical between firms, their responses to the institutional configuration will diverge and bring them on different development trajectories. We identify four distinct groups of observed trajectories, and argue for specific endogenous and exogenous factors that make firms from those groups within the institutional configuration react differently. The observed different responses to the established institutional framework are likely to be increasingly visible at times of or around major external change events affecting the industry as a whole (such as global financial crises, emergence or decline of markets etc.).