Summary: Pursuant to a congressional request, GAO provided: (1) information on limitations to federal agencies' reprogramming authority; and (2) a listing of federal trust funds. GAO noted that: (1) federal agencies have implicit authority to shift funds within an appropriation or fund account for purposes other than those that were intended at the time of appropriation; (2) agencies may not transfer funds between accounts without statutory authority to do so; (3) agencies are free to reprogram unobligated funds as long as the expenditures meet the appropriation's general purpose and do not violate any other specific limitation or are not otherwise prohibited; (4) Congress has generally provided guidelines or nonstatutory instructions to agencies on their reprogramming authority and frequently requires agencies to notify it when reprogramming occurs; (5) courts have held that the nonstatutory limitations are not binding on agencies, but agencies comply to keep faith with their appropriate committees; and (6) the list of trust funds includes both revolving and nonrevolving trust funds and special fund accounts, since they are similar to trust fund accounts, that appear in the President's 1997 budget.