Commodity trade is central to the global economy but is also associated with socio-environmental impacts, for example, deforestation, especially in producer countries. It is crucial to understand how geographic sourcing patterns of commodities and commercial relationships between places and actors influence land-use dynamics, socio-economic development, and environmental degradation. Here, we propose a concept and methodological approach to analyze the geographic stickiness of commodity supply chains, which is the maintenance of supply network configurations over time and across perturbations. We showcase policy-relevant metrics for all Brazilian soy exports between 2003 and 2017, using high-resolution supply chain data from www.trase.earth. We find that the Brazilian soy traders with the largest market share exhibit stickier geographic sourcing patterns, and that the supply network configurations between production places and traders become increasingly sticky in subsequent years. Understanding trade stickiness is crucial for supply chain accountability, because it directly affects the effectiveness of zero-deforestation commitments.