The unwillingness of team owners to share their data prohibits a direct assessment of the value of professional team sports ownership. But insights into that value can be gleaned from actual team sale prices. First, throughout the entire modern history of Major League Baseball (MLB), the average real growth in team sale prices is twice the usual comparison value of 3% for the economy at large. Second, aggregated at the franchise level, the average rate of growth is about 1.6 times the 3% comparison. Third, the real growth rate an owner can expect from time of purchase to time of sale over the decades has been a roller-coaster ride. Fabulous growth occurred to the 1940s, fell off dramatically to the 1970s, rebounded very strongly in the 1980s, and was essentially zero in the 1990s. In addition, there appears to be a strong relationship between risk and return, owners have learned to price expansion franchises close to discounted expected future profits, the period of ownership has shown dramatic declines at two distinct points in time, and the portion of ownership value not associated with annual operations appears to be significant. This information has implications for claims of losses by owners and for future analysis.