48 CFR §1516.303-71

Cost-sharing is a generic term denoting any situation where the Government does not fully reimburse a contractor for all allowable costs necessary to accomplish the project under the contract. This term encompasses cost-matching and cost-limitations, in addition to cost-sharing. Cost-sharing does not include usual contractual limitations such as indirect cost ceilings in accordance with FAR 42.707, or ceilings on travel or other direct costs. Cost-sharing contracts may be required as a result of Congressional mandate.