This chapter will continue the analysis of integration but shift emphasis to unrelated diversification and multinational development. Transaction cost contributions in these areas are different from the subject matter discussed in Chapter 5, hence their separate development. The discussion is organised as follows. First Oliver Williamson’s arguments accounting for conglomerate development will be introduced and assessed. To anticipate this analysis it can be pointed out that the main conclusions drawn are critical of transaction cost reasoning in this area; alternative, non-contracting perspectives are stressed. Following this the chapter will turn to multinational development. The objectives here are twofold. First to introduce transaction cost formulations in this area, and secondly on the basis of this discussion to fill gaps left in earlier analysis, particularly that of the previous chapter.