Although today’s public markets echo ancient market forms, they incorporate many original aspects which merit scrutiny because: 1) they are connected to a dominant neo-liberal market functioning and structures; and 2) they illuminate important tensions that question how sustainability is practicable at a macro level. Taking an ecological perspective, we show that public markets bring certain benefits in relation to sustainability. Significantly, however, we illustrate how these perceived benefits are underpinned by three compromises or "trade-offs" that public markets also invoke and that operate at inter-social, inter-nation, and inter-gender levels. We argue that what may look sustainable on a local level can raise challenges to macro sustainability more broadly conceived. Our contribution is twofold. First, we offer an updated, comprehensive definition of public markets and discuss to what extent they may represent a megatrend. Second, we contribute to the literature on sustainability by conceptualizing the notion of ecological sustainability, which suggests that an overarching analysis of sustainability reveals possible internal trade-offs between its economic, social, environmental, and ethical constituents, which the case of public markets helps highlight