European governments frequently finance defence technology before a product has a commercial market beyond the original military requirement. The economic relationship does not necessarily end with the development contract. A state may retain rights over technical information, negotiate royalties on later sales, recover the cost of publicly financed tooling, license publicly owned intellectual property, preserve a shareholding in a spin-out, or make subsequent exploitation conditional on payments or permissions. These mechanisms are easily collapsed into the language of a public “return on investment”, but that expression conceals materially different legal and financial claims. A contractual royalty is not ownership of the technology; ownership is not freedom to manufacture it; an assessed claim is not cash; and a receipt credited to a defence budget is not evidence that an equivalent amount has produced additional operational capability. The question for European rearmament is therefore not simply how much money governments can recover from successful defence technologies. It is how public financing is translated into enforceable rights after development, when those rights become collectible, and whether their design preserves public value without impairing co-investment, cross-border technological reuse or the industrial incentives required to expand European defence capacity.