Centralization versus decentralization: Risk pooling, risk diversification, and supply chain disruptions

• We model a multi-location supply chain where supply may be disrupted.
• We show that decentralizing inventory reduces cost risk through risk diversification.
• Risk diversification tends to have a stronger effect than demand risk pooling.
• Therefore a risk-averse firm should typically choose to decentralized inventory.

We investigate optimal system design in a multi-location system in which supply is subject to disruptions. We examine the expected costs and cost variances of the system in both a centralized and a decentralized inventory system. We show that, when demand is deterministic and supply may be disrupted, using a decentralized inventory design reduces cost variance through the risk diversification effect, and therefore a decentralized inventory system is optimal. This is in contrast to the classical result that when supply is deterministic and demand is stochastic, centralization is optimal due to the risk-pooling effect. When both supply may be disrupted and demand is stochastic, we demonstrate that a risk-averse firm should typically choose a decentralized inventory system design.