This rulemaking provides rules concerning the limitation on the deduction for business interest expense after amendment of the Internal Revenue Code (Code) by the Tax Cuts and Jobs Act, which was enacted on December 22, 2017.  Specifically, these proposed regulations provide rules that characterize interest expense associated with debt proceeds of partnerships and S corporations (passthrough entities), including where debt is used to fund distributions and debt proceeds of partners or shareholders allocated to the acquisition of an interest in a passthrough entity. These proposed regulations provide rules for how the business interest deduction limitation rules under section 163(j) apply to United States shareholders, as defined in section 951(b), of controlled foreign corporations, as defined in section 957(a), and to foreign persons with effectively connected income in the United States. Finally, these proposed regulations also provide guidance regarding the definition of real property development and real property redevelopment, and the definition of a syndicate for purposes of sections 163(j) and 1256. These proposed regulations affect taxpayers that have business interest expense, particularly passthrough entities, their partners and shareholders, as well as foreign corporations and their United States shareholders and foreign persons with effectively connected income. These proposed regulations also affect RICs that have business interest income, RIC shareholders that have business interest expense, and members of a consolidated group.