The Debt Limit: History and Recent Increases by Andrew Austin, Mindy R. Levit published by Congressional Research Service (2010).
“Total debt of the federal government can increase in two ways. First, debt increases when the government sells debt to the public to finance budget deficits and acquire the financial resources needed to meet its obligations. This increases debt held by the public. Second, debt increases when the federal government issues debt to certain government accounts, such as the Social Security, Medicare, and Transportation trust funds, in exchange for their reported surpluses. This increases debt held by government accounts. The sum of debt held by the public and debt held by government accounts is the total federal debt. Surpluses generally reduce debt held by the public, while deficits raise it…”
Federal Debt and the Statutory Limit, November 2013 published by Congressional Research Service (2010).
“The debt limit—commonly referred to as the debt ceiling—is the maximum amount of debt that the Department of the Treasury can issue to the public and to other federal agencies. That amount is set by law and has been increased over the years in order to finance the government’s operations. The debt ceiling was suspended earlier this year—from February 4 through May 18—so that the Department of the Treasury had the authority to borrow any amounts necessary to meet the government’s operating needs during that period. The debt limit has again been suspended, this time through February 7, 2014…”
