According to a recent review of the AUKUS nuclear submarine deal done by the Parliamentary Budget Office (PBO), over $123 billion has been set aside as a "contingency" for Australia's greatest ever defence investment. The $368 billion nuclear-powered submarine program's breakdown of costs discloses that Defence has budgeted $123 billion for a 50% contingency that is not allocated by year but rather "is triggered on the occurrence of a contingent event."