What are the main sources of supply chain risk?

Supplier reliability, demand volatility, geopolitical issues, and long lead times. These rarely act alone. A long lead time becomes a real problem when demand variability is high or supplier reliability slips, and geopolitical pressure tends to amplify both. Treating each source in isolation produces point fixes that do not last, while modeling demand uncertainty and lead time variability together exposes the SKUs where exposure is concentrated. That view supports better decisions on dual sourcing, inventory placement and contractual flexibility, and it allows planners to prioritize the few items where mitigation actually pays back rather than spreading effort across the full portfolio with little measurable effect.