Firms trading over-the-counter (OTC) derivatives in the US, or US residents buying foreign OTC derivatives, must report the details of the trade to a Swap Data Repository (SDR). However, Dodd-Frank requires only single-sided reporting. Who should report the transaction is based on several criteria, including the type of asset being traded and the types of firms involved in the trade. Different criteria apply depending upon if one or both counterparties are US citizens. Entity types are ranked hierarchically with regards to reporting obligations, with Swap Dealers at the top.