Why is it that exporter productivity premia (EPP) differ so widely in size? We take this question to the theory and to the data. We derive the sectoral EPP in a standard heterogeneous firms trade model and apply the insights from the model to 13 years of data for all Danish manufacturing firms....

An astonishing 33% of all firm-product-destination export spells in Danish data turn out to be isolated single-month one-off export events (observed once in a 49 month window). On average, for an export-active firm, such one-off exports account for 17% of total foreign sales. These patterns...