The U.S. Constitution vests Congress with the "power of the purse," and funds may only be drawn from the Treasury in consequence of appropriations made by law. Enacted appropriations and other budgetary legislation may vary in the level of detail they provide regarding how agencies should spend the funds that have been provided. Even when the purpose of appropriations has been specified in great detail, agencies have often been provided with some flexibility to decide how they will use their available budgetary resources during the fiscal year. In some instances, agencies are provided with limited authority to shift funds from one appropriations account or fund account to another—commonly referred to as "transfer authority." In addition, agencies are generally permitted to shift funds from one purpose to another within an appropriations account. This practice, usually referred to as "reprogramming," may be restricted by statute. While the terms reprogramming and transfer are sometimes used interchangeably, the two terms each represent distinct budgetary actions with different statutory limitations. In order to differentiate between a reprogramming action and a transfer action, it may be necessary to understand the structure of the accounts involved and the range of activities and programs typically funded by each account. For example, in FY2013 there were more than 30 accounts within the Department of Justice Appropriations Act, including an account for "Federal Bureau of Investigation (FBI), Salaries and Expenses" and an account for "Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), Salaries and Expenses." Given the range of activities typically funded by these two accounts, a transfer would occur if funds originally appropriated for FBI salaries and expenses were moved and then used to pay for ATF salaries and expenses. The Department of Justice Appropriations Act also includes an account for "U.S. Attorneys, Salaries and Expenses." This account provides funding for a range of activities, including criminal litigation, civil litigation, and continuing legal education of U.S. attorneys. In this example, a reprogramming would occur if funds originally allocated for criminal litigation expenses were shifted and then used to pay for civil litigation expenses or for continuing legal education expenses. In the first example, funds are transferred from the "FBI, Salaries and Expenses" account to the "ATF, Salaries and Expenses" account, while in the second example funds are reprogrammed from one activity to another within the "U.S. Attorneys, Salaries and Expenses" account. In each example, whether the budgetary transaction is a transfer or a reprogramming depends, in part, on the structure and contents of the appropriations accounts involved. This report provides an overview of transfers and reprogramming, and describes the statutory limitations and requirements for congressional notification that are applicable to each. This report concludes with a brief discussion of the following possible issues for Congress: (1) agency reporting and congressional oversight of transfers and reprogramming actions, (2) the potential burden of transfer and reprogramming notifications, (3) excessive or improper use of transfer and reprogramming authorities, and (4) financial management and budgetary treatment of transferred funds. Transfers (i.e., the shift of budgetary resources from one appropriations or fund account to another) typically involve movement of funds within an agency or department, but may also involve movement of funds between two or more agencies or departments. An agency or department may only transfer budgetary resources if it has been provided the statutory authority to do so. A general restriction on transfers may be found in 31 U.S.C. Section 1532, which provides, in part, "An amount available under law may be withdrawn from one appropriation account and credited to another or to a working fund only when authorized by law." According to the Government Accountability Office (GAO), all transfers are prohibited without statutory authority, including "(1) transfers from one agency to another, (2) transfers from one account to another within the same agency, and (3) transfers to an interagency or intra-agency working fund. In each instance statutory authority is required." Without prior statutory authority, an agency may not use budget authority from one appropriations account to pay for programs, projects, or activities (PPAs) that are typically funded by another account. Without statutory authority, an agency may not use excess funds in one account to offset potential deficiencies in another account, or shift funds from a project it considers a low priority to a project funded by a different account that it considers a higher priority. Transfer authority may be broad or narrow in scope and it may apply to all agencies, to select agencies, or only to a single agency. Transfer authority may also be limited to a specific dollar amount. Alternatively, transfer authority may be "indefinite" (i.e., provided without a specific limit on the dollar amount that may be transferred). Indefinite transfer authority is typically provided with specific restrictions on the circumstances under which the authority may be used. Transfer authority may be provided either in authorizing statutes or in appropriations acts. In addition, statutory provisions that provide transfer authority will typically require the agency or department to notify Congress a certain number of days (often 15, 30, or 45 calendar days) prior to transferring funds. Transfer authority in annual appropriations acts provides agencies with limited discretion to shift budget authority from one appropriations account or fund account to another. Within annual appropriations acts, transfer authority may be provided to a specific department or agency. Transfer authority may also be provided for a specific account, program, or purpose. Department-wide and agency-wide transfer authorities are often found in the sections of appropriations acts titled "General Provisions." Department-wide and agency-wide transfer authorities are typically provided with specific limitations on the overall amount that a department or agency may transfer amongst its accounts in a given fiscal year. Additionally, there may be limits on the amount that any single account may be augmented by incoming transfers. For example, the FY2013 department-wide transfer authority provision for the Department of Commerce states "not to exceed 5 percent of any appropriation made available for the current fiscal year for the Department of Commerce in this Act may be transferred between such appropriations, but no such appropriation shall be increased by more than 10 percent by any such transfers." In the above example, 5% is the limit on how much may be transferred out in total. In other words, the total amount of transfers carried out by the Department of Commerce may not exceed 5% of the total amount the department was appropriated for FY2013. The 10% figure is the maximum amount that any single account may be augmented by incoming transfers. In other words, each account for the Department of Commerce may be increased by a maximum of 10% of its original appropriation. For example, an account that was originally appropriated $10 million may accept a maximum of $1 million in incoming transfers. Transfer authority may also be found in the paragraphs of an appropriations act that specify the amount of budget authority being provided to each account. Account-specific transfer authorities allow agencies to transfer funds among specific accounts. Account-specific transfer authority may be limited to a specific dollar amount. For example, in FY2012 the Secretary of the Interior and the Secretary of Agriculture were authorized to transfer up to $50,000,000 of funds appropriated for wildland fire management "when such transfers would facilitate and expedite wildland fire management programs and projects." Alternatively, account-specific transfer authority may be indefinite with respect to amount, and limited only to the amount of funds available. In such cases, the authority is often provided with specific restrictions on the purposes for which the authority may be used. For example, in FY2012 the Secretary of the Treasury was provided indefinite authority to "transfer funds from Financial Management Service, Salaries and Expenses to the Debt Collection Fund as necessary to cover the costs of debt collection." While transfer authority provided in annual appropriations acts is often limited to a specific dollar amount or percentage of the total budget authority provided, transfer authority in authorizing statutes is often broad or indefinite (i.e., provided without explicit caps on the amount of funds that may be transferred). Generally, when indefinite transfer authority is provided in authorizing statutes, it is accompanied by specific restrictions on the circumstances under which the authority may be used. In addition, restrictions on indefinite transfer authority may be imposed by subsequently enacted legislation, such as annual appropriations acts. Under 31 U.S.C. Section 1531(a), executive agencies may transfer funds when the responsibility to carry out the functions or activities for which the funds were provided is transferred from one agency to another. This provision also applies when a function or activity that was previously under the jurisdiction of a single agency becomes the shared responsibility of two or more agencies. The balance of an appropriation available and necessary to finance or discharge a function or activity transferred or assigned under law within an executive agency or from one executive agency to another may be transferred to and used (1) by the organizational unit or agency to which the function or activity was transferred or assigned; and (2) for a purpose for which the appropriation was originally available. It is important to note that the above provision provides executive agencies with authority to transfer funds only when there is a corresponding transfer of function authorized by law. In cases of governmental reorganization, the authority to transfer funds may be temporary, periodic, or both—whichever is best suited for the associated transfer of function authorized by law. Generally, the authority to transfer funds ceases when the associated transfer of function or transition period is complete. One recent example of government reorganization was the establishment of the Department of Homeland Security. The Homeland Security Act of 2002 (HSA, P.L. 107-296 ; 116 Stat. 2135) provided for the transfer of multiple functions to the newly created Department of Homeland Security (DHS). To facilitate the transfer of functions, the HSA included multiple provisions authorizing the transfer of funds from these departments and agencies to DHS.