Ownership changes are common across firms of all sizes, and they have meaningful impacts on subsequent firm performance. Using a panel of Canadian administrative data, we document that sales are an important margin in the firm life cycle, larger than exit rates for employer firms. Applying an event-study framework, we find that (a) survival rates initially decline post sale, leveling off after three years and (b) conditional on survival, profits are permanently higher. Embedding firm sales in a model of firm dynamics, we show that sales are quantitatively important to understanding entry, growth, and exit dynamics. We estimate that 13% of entrants survive exclusively due to the option value of sale. Among small firms, 18% of average log employment growth is accounted for by realized ownership changes. In the stationary distribution, firm sales operate at the tails, allowing smaller firms to survive and magnifying the size of the top firms. Finally, we quantify the importance of incorporating ownership changes for understanding the aggregate response to policy changes.