The mechanism: Since FY2022, Congress has attached a dedicated Submarine Industrial Base (SIB) appropriation to the annual defense budget — separate line-item money, running into the billions cumulatively, meant to fix the supplier bottlenecks and workforce shortages that have both the Virginia-class attack submarine and Columbia-class ballistic-missile submarine programs running behind schedule. AUKUS raised the stakes further: the U.S. committed to selling Virginia-class boats to Australia starting this decade, which means the SIB money now has to fund a submarine build-rate increase, not just stabilize the existing one. That cash flows through the Navy to two shipyards — General Dynamics' Electric Boat (Groton, CT / Quonset Point, RI) and HII's Newport News Shipbuilding (Virginia) — and hundreds of second- and third-tier suppliers. But the two primes don't compete for this money so much as split it by design: Electric Boat is lead yard on both Virginia and Columbia construction, while Newport News builds the aft/stern sections of Virginia-class boats as a subcontractor to GD and is the sole builder of nuclear aircraft carriers.