A black budget is a budget that is allocated for classified and other secret operations of a nation, a corporation, a society of any form, a national department, and so on. A black budget usually covers expenses related to military research and covert operations. The black budget is mostly classified due to security reasons.
The United States Department of Defense has a black budget it uses to fund black projects—expenditures it does not want to disclose publicly. The annual cost of the United States Department of Defense black budget was estimated at $30 billion in 2008 but was increased to an estimated $50 billion in 2009. A black budget article by the Washington Post, based on information given by Edward Snowden, detailed how the US allocated $52.8 billion in 2012 for the black budget.