Since social distancing is the primary strategy for slowing the spread of many diseases, understanding why U.S. counties respond differently to COVID-19 is critical for designing effective public policies. Using daily data from about 45 million mobile phones to measure social distancing we...

Most listed firms are freestanding in the U.S, while listed firms in other countries often belong to business groups: lasting structures in which listed firms control other listed firms. Hand-collected historical data illuminate how the present ownership structure of the United States arose: (1)...