Father of the retail clinic. Co-founded QuickMedx in 1999 after a bad emergency room experience with his son. Convinced him of the demand for convenient, appointment-free access to medical care. Early success spawned competitors. QuickMedx renamed MinuteClinic and later acquired by CVS. Krieger has since funded or helped found several successful healthcare startups, his most current being Zipnosis. It offers a "mobile app" Q&A to collect information from a patient that a doctor needs to make a diagnosis. We like their tagline: "Healthcare in your pocket."

Christensen in The Innovator's Prescription:

"Retail clinics are closer to a 'new market,' rather than 'low-end' disruption, in that they compete predominantly against nonconsumption. For example, over 60 percent of patients who receive care at retail clinics do not have a personal care physician at all."