“…For each flow of goods across a US border, this data set records the product classification(s) of the shipment ( ten-digit harmonized system (HS)), the value and quantity shipped, the date of the shipment, the destination or source country, the transport mode used to ship the goods, the identity of the US firm engaging in the trade, and whether the trade is with a related party or occurs at arm's length. 21 In our main results, we aggregate the establishment-level data from the CM and LBD and the trade transactions data up to the level of the firm. We thus obtain a data set for each firm that contains information on firm characteristics (e.g., industry, employment, productivity, and total shipments) as well as on each of the margins of firm international participation considered above (exports of each product, the number of products exported to each market, the num- 19 For further discussion of the CM see, for example, Bernard, Redding, and Schott (2010).…”