McKesson Corporation distributes pharmaceuticals and medical supplies to pharmacies, hospitals and other healthcare providers, one of the largest pharmaceutical distributors in the United States. Its distribution business serves as a critical supply chain link between drug manufacturers and the many pharmacies and healthcare providers who need reliable, efficient access to a vast catalog of pharmaceutical products. McKesson's scale as a distributor gives it significant purchasing power and logistics efficiency, advantages that smaller distributors or individual pharmacies couldn't replicate by dealing directly with numerous individual drug manufacturers. The company's revenue is tied to overall pharmaceutical spending and prescription drug volumes, which tend to be relatively stable and non-discretionary since prescription medications are a recurring healthcare necessity regardless of broader economic conditions.