Expenses for their assigned ships, squadrons, and other units APPROPRIATIONS The different types of appropriations are described in the following paragraphs. ANNUAL APPROPRIATION The annual appropriation is generally made for the current operating and maintenance expenses of the DON. It becomes available at the beginning of the fiscal year as designated by the appropriation act. These appropriations are available for payment of obligations incurred only during that fiscal year; however, they are available for payment of such obligations for 2 years thereafter. When the appropriation expires for obligations at the end of a fiscal year, the unobligated balance is transferred to the surplus of the Treasury. At the end of 2 years of availability y, the balance remaining, representing unliquidated obligations less reimbursements that are to be collected, is transferred to the successor account. CONTINUING APPROPRIATIONS A continuing appropriation is an appropriation that remains available until exhausted or until the purpose for which it is made has been accomplished. When the purpose of the continuing appropriation is accomplished, the amount equal to the total of unliquidated obligations, less the total of reimbursements to be collected, is transferred to the successor account. The remaining unobligated balance is transferred to the surplus of the Treasury. MULTIPLE-YEAR APPROPRIATIONS This appropriation is generally made for the oprating and maintenance expenses of the DON. It becomes available for obligations and expenditures at the beginning of the fiscal year designated in the appropriations act unless otherwise stated in the act. It is available for payment of obligations incurred only during the fiscal years specified in the act. However, it is available for payment of such obligations for 2 years thereafter. These 2 years maybe extended by Congress. At the end of the last fiscal year included in the appropriation, when the appropriation expires for obligation purposes, the unobligated balance is transferred to the surplus of the Treasury. At the end of the 2-year period of availability, the balance remaining (unliquidated obligations less reimbursements to be collected) in the account is transferred to the successor account. TRANSACTIONS All expenditures must have the authorization to be expended from available funds. Transactions develop through stages of reservation, commitment, obligation, and expenditure. RESERVATION A reservation is an administrative action that identifies funds set aside for planning purposes before establishing a commitment. Reservations are not maintained as part of official records. However, if a record is maintained, it is included in the minimum unofficial records of the holder of authorization or OPTAR. COMMITMENT A commitment is a firm reservation of funds based upon firm procurement directives, orders, requisitions, or an authorization to create obligations. OBLIGATION An obligation is incurred when an order is placed, a contract is awarded, a service is received, or a requisition is posted against the appropriation. EXPENDITURE An expenditure is the use of funds to cover obligations. Expenditures must be charged to the appropriate funds only. A fund is properly chargeable with all expenditures necessary to accomplish the purpose for which it is established. For example, the appendices of NAVSO P-3013-2 list the fund codes that need to be used for each specific material or services. ACCOUNTING SYMBOLS The charges and credits to appropriations and funds are reported to the Comptroller of the Navy. The report is used to update the status of the appropriation and fund. Symbols are used to identify charges and credits to appropriations instead of using titles. The appropriation symbol is used in preparing documents for contracts, Material Inspection and Receiving Report, DD Form 250, and Requisition and Invoice/Shipping Document, DD Form 1149. The 6-5