A black budget or covert appropriation is a government budget that is allocated for classified or other secret operations of a state. The black budget is an account of expenses and spending related to military research and covert operations. The black budget is mostly classified because of security reasons.
A black budget can be complicated to calculate, but in the United States it has been estimated to be over US$50 billion a year, taking up approximately 7 percent of the US$700 billion military budget.[1]