ach, not the UN, NATO, was it? One of those big first-world alliances with lots of power, not just political. 

and I don't think that INTERPOL would be able to focus on a global corporation that has no real consistent location after a world war. 

And I would have it so that the designs and the like are exclusive, but the technology itself isn't. If an entity funds the research of, say, a special railgun tank, with some kind of fancy laser cannon on top for use against, say, drones or mines, then the tank itself would be exclusive to that investor, but the stuff and know-how would just be re-designed into something else to sell to the highest bidder. The quality and quantity of that item, however, would be decided by the amount invested. If someone invested a great deal for something, then the publicly-sold resdesign of it wouldn't be as good, to make the exclusive models better and more valuable. 

And if the APIRCA were to be branded a terrorist organization, then so what? How would they all be caught, with the world divided and in ruins? There are still naval fleets, sure, and satellites, but that doesn't necessarily mean that you'll be able to find them before they disappear again. They aren't exactly defenseless. The higher the priority, the more likely you won't be getting close. There will be, no doubt, better submarines, torpedoes, depth charges, anti-air laser turrets, railgun ship turrets, and missile defenses, as well as maybe one or two VTOL types that could be used.