structural:expansion, information:extraction
Related terms such as "national deficit" and "national surplus" most often refer to the federal government budget balance from year to year and not the cumulative amount of debt held. In a deficit year, the national debt increases as the government needs to borrow funds to finance the deficit. In a surplus year, the debt decreases as more money is received than spent, enabling the government to reduce the debt by buying back Treasury securities. Broadly, US government debt increases as a result of government spending and decreases from tax or other funding receipts, both of which fluctuate during a fiscal year. The aggregate, gross amount that Treasury can borrow is limited by the United States debt ceiling.