In theory, free entry can lead to social inefficiency. We study the radio industry in a first attempt to quantify this inefficiency. Using cross-sectional data on advertising prices, the number of stations, and radio listening, we estimate the parameters of listeners' decisions and of firms'...

In theory, free entry can lead to social inefficiency. When new products are substitutes for existing products, the business stolen from incumbents places a wedge between private and social benefits of entry. The business stealing effect can be offset if entry reduces prices or increases...

Free entry into markets with decreasing average costs and differentiated products can result in an inefficient number of firms and suboptimal product variety. Because new firms and products draw their customers in part from existing products, concentration can affect incentives to enter as well...