Analyses of the private pension system typically focus on such issues as how to improve overage or encourage saving or prevent tax abuse or generate retirement income more equitably. Those issues are important, but the thesis of this paper is that more attention needs to be paid to the structure in which they are embedded. It examines the nuts-and-bolts of the private pension system, that is, the plans that comprise it and the rules that govern them. The architecture and machinery of the private pension system have much to teach us about directions for reform.