On September 1, 2026, the Cost Accounting Standards Board (CASB) issued a final rule, effective October 1, 2026, that explains when and how CAS applies to contracts. 91 Fed. Reg. 56056. The final rule increases the monetary thresholds for CAS coverage, changes how CAS applies to indefinite delivery contracts (IDCs), expands agency waiver authority, and, critically, permits exemptions for portions of hybrid contracts.