Some owners of private firms who cash out their investments sell their firms all at once. Others sell part of the firm in an initial public offering (IPO), then sell the remainder shortly after the IPO. Using a unique data set from IPO filings we find that the expected payoff to going public before selling the firm is 200 percent higher than selling privately. One explanation for these different valuations is that public markets are more competitive than private markets for corporate assets. An alternative explanation is that the going public process is a screening mechanism; public firms have higher valuations because they are better firms. We test between these two explanations. The results suggest that listing shares in public equity markets enhances the value to owners who want to cash out their investments because the IPO process acts as a screening device of a firm's quality. JEL Classification: G32, G34