Most theories of strategic change focus on how large, established firms recognize or fail to recognize the need for strategic change. Little research examines how early-stage entrepreneurs decide when and how to change their strategies. With a longitudinal field study of seven entrepreneurial firms developing innovations in energy and cleantech, we examined 93 strategic decisions at risk for change. We found that decision-makers chose to change their strategies only after new information conflicted with or expanded their beliefs. Furthermore, a pivot, or strategic reorientation, was not achieved with a single decision, but by incrementally exiting or adding strategy elements over time, accumulating into a pivot. We contribute a grounded definition of what constitutes a pivot and explain when and how entrepreneurial firms pivot.