ResMed dominates the treatment of sleep apnea with its CPAP machines and masks, a condition that is chronic, underdiagnosed and increasingly screened for. Masks and accessories wear out and are replaced on schedule, creating a consumables stream atop the device sales. Cloud connectivity in every machine feeds adherence data to physicians and insurers, and a software division manages care outside hospitals. Founded in 1989 and headquartered in San Diego, ResMed shares the global market mainly with Philips, whose product recall reshaped competitive dynamics.