How do you prevent stockouts on best-selling products?

Best-sellers concentrate revenue and concentrate stockout risk, so they deserve stricter rules than the rest of the catalogue. First, size their buffer against the upper range of demand, not the average: probabilistic forecasts and dynamic safety stock are non-negotiable on top movers. Second, monitor supplier lead time against contract specifically on these SKUs, because a late delivery here is far more expensive than on a slow mover. Third, pull commercial signals early: every promotion or campaign on a top mover should flow into the demand plan before it launches, not after. The combination is what keeps a best-seller available through exactly the demand spikes that would otherwise drain it.