Health insurance in the United States is typically provided by a managed care plan with a preferred or exclusive "network" of providers; balance billing does not occur with providers in-network, as the insurer negotiates an agreed rate ahead of the service. However, out-of-network medical billing has become common for privately insured patients even when they receive care in an in-network hospital, creating a substantial financial burden. Surprise balance billing is when an out-of-network provider bills an individual for services that were not covered by the insurance plan. This is often a surprise because an individual may be unaware that the services were out-of-network or did not actively choose to receive in an inpatient setting. The "growing risk to patients of incurring burdensome unexpected out-of-network bills" has received significant attention in the 21st century.
