The problem for developers of Generation IV nuclear power plants is that it is too early in the development process for investors and potential customers to bet significant money on the winners from an increasingly crowded field. A working prototype would give developers a reactor model they could sell to customers. As yet, no one has got that far.New patterns of investment could help. Public-private partnerships for reactor development, of the type formed by NuScale and the Bill Gates-backed TerraPower, both with the US Department of Energy, are creating opportunities for entrepreneurial developers who can harness the knowhow and get access to funds.