The Federal budget and budget process largely use obligational accounting–a distinct administrative control through which Federal agencies control, monitor, and report on the status of funds at their disposal. Unexpended budget balances consist of the unobligated and obligated, but unliquidated, budget balances.
Unobligated budget balances, including amounts for trust funds, are the cumulative amount of budget balances that are not obligated and that remain available for obligation. In 1-year accounts, the unobligated balance is not available for new obligations after the end of the fiscal year. In multiyear accounts, the unobligated balance may be carried forward and remains available for obligation for the period specified. In no-year accounts, the unobligated balance is carried forward until specifically rescinded by law or the head of the agency concerned determines that the purposes for which it was provided have been accomplished and disbursements have not been made against the appropriation for 2 consecutive years. The total unobligated budget balances as of September 30, 2011, and 2010, are $829.4 billion and $885.1 billion, respectively.
Obligated budget balances are the cumulative budget balances that have been obligated but not liquidated. The obligated balance can be carried forward for a maximum of 5 years after the appropriation has expired. The total obligated budget balances as of September 30, 2011, and 2010, are $1,428.5 billion and $1,530.9 billion, respectively.
The President's Budget is located at www.whitehouse.gov/omb; unexpended budget balances are shown in the supporting documentation section under "Balances of Budget Authority." The President's Fiscal Year 2013 Budget (issued on February 13, 2012) includes the actual unobligated and obligated amounts for fiscal year 2011. The President’s Budget with fiscal year 2012 actual amounts is expected to be published in February 2013.