In an article in the Revista Mexicana de Sociología, the sociologist Héctor Castillo Berthier described the traders of La Merced, the Mexico City market that preceded the Central de Abasto. The traders followed customary norms rather than formal law. They kept “un riguroso código de honor,” a strict code of honor, and their deals were not made in writing, with notes and receipts.
The large wholesalers extended credit to the smaller traders, and the credit bound the smaller traders to them.