Inorganic phosphate-based fertilisers have done much to alleviate the grave problem of global hunger, yet these gains have also come at the expense of a critical dependence on a finite mineral resource. According to various projections, current economic global reserves of phosphate rock, approximately 90% of which is used to manufacture chemical fertilisers, are diminishing and will be depleted within as few as 40-“150 years -“ a phenomenon commonly known as peak phosphorus. This article argues that much like the idea of peak oil before it, the peak phosphorus claim tends not to distinguish between long-term concerns about one day -running out of phosphate rock and the more immediate, multi-dimensional socio-economic causes and effects of poor resource management. The article shows the importance of a more nuanced understanding of the problem of resource scarcity to the sustainable investing agenda. In particular, the concentration of the majority of remaining global phosphate reserves in a handful of geopolitically sensitive countries and state-capitalist corporations presents a number of unexplored challenges to investors.