Private equity funds, mostly domiciled in secrecy jurisdictions, are dominant investors in the resource-based economies of Africa. Some of the investments that these funds make have been speculative and based on perceived high-value ‘futures’ in biodiversity, bio-fuels and land, carbon capture or strategic minerals. However, private equity funds are also heavily invested in mining, energy and infrastructure, which also generate wealth from the non-human world; ‘old’ markets alongside the ‘new’ markets for discovered nature-based commodities. This article reviews how private equity funds, and their partners in development finance institutions, frame and value the consequential impact of their industries on people and things. It then explores how this valuation, and other related calculative technologies of ‘concern’ for the ‘environment’— such as risk assessment and offsetting — are incorporated into firms’ investment decision making. This enquiry finds that: 1) financiers currently employ thin, partial and pseudo-mathematical methods of assessing environmental impact and worth; and 2) that environmental and developmental impact ‘science’ is a performative technology, with only marginal relation to the material world it seeks to measure and protect. Using calculative technologies in which financial considerations are privileged, financiers have wrought a dissociated, incomplete and partial valorization of the non-human world. Nonetheless, 3) these calculative devices assist in legitimizing private equity funds as institutional leaders in pre-existing power structures which exploit natural resources in Africa for the benefit of money-holders. These propositions roughly correspond to the technical, empirical and theoretical dimensions of a socio-technical arrangement applying to nature-based accumulation, which, overall, performs a political process of financialization.