This document finalizes rules related to certain provisions of the No Surprises Act regarding the Federal independent dispute resolution (IDR) process, which was established as part of the Consolidated Appropriations Act, 2021 (CAA). This rule sets forth new requirements relating to the disclosure of information that group health plans and health insurance issuers offering group or individual health insurance coverage must include along with the initial payment or notice of denial of payment for certain items and services subject to the surprise billing protections in the No Surprises Act. This rule also requires plans and issuers to communicate information by using claim adjustment reason codes (CARCs) and remittance advice remark codes (RARCs), as specified in guidance, when providing any paper or electronic remittance advice to an entity that does not have a contractual relationship with the plan or issuer. This document also amends certain requirements related to the open negotiation period preceding the Federal IDR process, the initiation of the Federal IDR process, the Federal IDR dispute eligibility review, and the payment and collection of administrative fees and certified IDR entity fees. This document also defines bundled payment arrangements, amends requirements related to batched items and services, and amends the rules for extensions of timeframes due to extenuating circumstances. Additionally, this document requires plans and issuers to register in the Federal IDR portal.