Agricultural markets are a prime object of what the anthropologist Clifford Geertz called ‘theoretical diffusion’ (Geertz 1973). In this diffused context, Henry Bernstein used an approach developed by French scholars, ‘filières vivrieres’, to analyse the ethnicized concentration of capital in South African maize markets (Bernstein 1996). The first part of this essay critically introduces the background to this approach, and Bernstein's development of it, to examine capital accumulation and public and private regulation. The second part merges insights from filières with a systems approach to post‐harvest activity. It revisits four decades of research on South Indian agriculture and its paddy‐rice markets to show how petty production and trade can coexist with capitalist accumulation, showing how, to what extent and why the relations of agricultural commodity marketing ‘fail to complete’ the process of polar class differentiation and consolidate petty commodity production in the post‐harvest sphere of circulation – the filière – as well as in production.