Amongst the market-based instruments designed to protect biodiversity, some directly target acquisition of land-use rights to turn natural forests into conservation areas and protect them against destructive activities such as logging or agricultural conversion. Whereas some instruments, such as Transferable Development Rights and Conservation Easements, require the privatisation of land, conservation concessions are based on financial compensations to the state, logging companies and local populations against their rights to ‘develop’ these lands. This principle of ‘rent for development swaps’ embodied in three instruments designed for buying back land use rights must be discussed according to efficiency and equity criteria. Four issues are critical in this respect: the property rights structure, prevailing local representations, the size of the area concerned and existing institutional arrangements regarding forest resource access cost. This paper suggests that the opportunity cost of setting up large scale conservation concessions is much higher than generally suggested, especially in countries which have moved away from former discretionary allocation practices and have reformed their forest sector regulation framework according to prominent donors' recommendations. It concludes that using the so-called ‘lower cost of conservation’ in poorest countries, which makes large scale operation affordable for conservation investors, also raises ethical issues, since this means compensating stakeholders at their current poverty level.