# Single-Source Dependency ## Definition A supply chain condition in which a buyer relies on one supplier for a critical component or material with no readily substitutable alternative. Single-source situations arise from supplier specialisation, geographic concentration of competent producers, or deliberate buyer policy maximising scale economies with a preferred partner. During disruptions, a single-sourced supplier in a critical category temporarily possesses monopoly-like pricing power, as the buyer has no alternative and demand is inelastic in the short run. ## Source Market Structure in Modern Supply Chains, §Market Concentration and Single-Source Dependencies ## Supply Chain Domain Risk ## VSM Assignment S4 — Single-source dependency is an intelligence failure at the S4 level: the supply chain's environmental scanning has not identified and mitigated the concentration risk. Resolving it requires S4 action — supplier development, geographic diversification, or technology substitution. ## WoN Concept Monopoly in Trade — Smith argues that monopolists charge the highest price buyers will bear, and that this price is always above the competitive level. A single-source supplier during a supply disruption is a temporary monopolist: buyers cannot immediately switch, demand is inelastic, and the supplier can extract above-normal prices. Smith's analysis of how monopoly restricts supply and raises price applies directly to the disrupted single-source scenario, even though in normal conditions the same supplier may operate competitively.