In fact, it varies from department to department. In general, departments should be doing what we call risk management and cash management. We're talking about twenty billion dollars out of a budget that exceeds $500 billion. For some departments, it would be a little more difficult. Indeed, they would have to defer certain expenditures to subsequent years.
That said, this would probably not be the case for all government departments and agencies. For example, the Department of National Defence has a budget in the tens of billions of dollars. In general, some appropriations lapse each year, particularly for capital expenditures in this department.
Often, 14% to 19% of capital budgets go unused from one year to the next. It is therefore quite possible that many, if not the vast majority of departments, reallocate funds from one envelope to another to make ends meet. However, this is not possible for all organizations requesting funds.