Market Access Constraints and Commodity Price Volatility in Fragile Economies: An Empirical Analysis of Agricultural Value Chains in Post-Conflict South Sudan

Background Market instability remains a persistent challenge in fragile economies, particularly in post-conflict contexts such as South Sudan. Agricultural producers in these settings face severe price volatility, driven by weak infrastructure, limited market access, and recurring insecurity. This study examined the link between market access constraints and commodity price volatility within South Sudan’s agricultural value chains, focusing on how road quality, information asymmetry, and conflict events affect welfare outcomes for rural households.  Methods A mixed-methods approach was adopted using time-series data from 2014–2024, covering major agricultural markets across five regions. Price volatility was estimated through a Generalized Autoregressive Conditional Heteroskedasticity (GARCH) model, while causal relationships between volatility and welfare indicators were analyzed using Two-Stage Least Squares (2SLS) regression with rainfall, road density, and conflict frequency as instrumental variables. Supplementary qualitative data from key informant interviews contextualized the econometric findings.  Results and Findings The results revealed that high price volatility significantly reduced household income by 8.2% and food consumption scores by 3.9 units (p < 0.001). Poor road networks and limited access to market information amplified volatility effects, particularly in remote counties. Policy simulations suggested that rehabilitating 500 km of rural roads, improving information access by 25%, and reducing conflict by 40% could jointly decrease price volatility by 18.5% and increase average household income by 24.6%. These findings underscore the structural nature of market inefficiencies in South Sudan’s fragile post-war economy.  Conclusion Market access constraints are central drivers of commodity price instability in South Sudan. Targeted investments in rural infrastructure, peace enforcement, and information systems can mitigate volatility and enhance agricultural welfare. Addressing these systemic barriers is essential for stabilizing rural livelihoods and promoting long-term economic recovery.