Recently, scholars have begun to show a reorientation of the Marshallian Industrial District (MDI) framework towards addressing topics that were not central to the mainstream, such as multinationals and their different sub-lines of research. In this study, we reflect on multinationals and their challenge to the established MID boundaries. By reviewing literature, we elaborate on, integrate and discuss types and effects of multinationals in districts, highlighting a new type of actor that has recently become more prominent: multinational private equity funds in MIDs. We elaborate on different types of multinationals in MIDs, reviewing and integrating extant evidence about private equity funds as new established realities. The study proposes new sub-lines of inquiry to extend and strenghten the MID framework.