Cost Accounting Standard (CAS) 405 requires that expressly unallowable costs be identified and excluded from any billing, claim, or proposal applicable to a government contract. For this reason, it is important to understand what types of costs are unallowable.

Corporate Topical Manual F200 defines the criteria to be followed for identifying and segregating allowable and unallowable costs. For questions, contact the Government Financial Relations Department (O74).