This paper analyzes cash flow and cost of capital dynamics around share repurchase announcements of publicly traded US firms by decomposing stock returns into news related to cash flows and discount rates. After repurchase announcements, the cost of capital decreases significantly, while cash flows do not change. The decrease in the cost of capital is largest for firms that appear underpriced. These firms also experience the highest long-term returns after repurchase announcements. The findings suggest that market participants learn about a temporary overestimation of the cost of capital when firms announce share repurchases.