Rocco Femia and Megan Kirmil write that the primary focus of the Proposed Regulations and the Audit Checklist is on the issues raised by so-called ‘‘buy-in’’ transactions – that is, transactions by which a participant that makes preexisting intangible property available for use in the cost sharing arrangement is compensated by the other participants. These issues are high stakes and conceptually difficult, and the resolution of these issues could have a significant impact on the transfer pricing principles applicable to transfers of intangible property and similar transactions.