Healthcare is one of the largest industries in the United States, but whether it is the single largest depends on how "biggest" is measured (such as by revenue, employment, or economic output).
The healthcare and social assistance sector is the largest employer in the US, according to data from the US Bureau of Labor Statistics. It employs more people than any other sector, with millions working in hospitals, outpatient centers, nursing facilities, and related services.
The healthcare industry also represents a significant portion of the US Gross Domestic Product (GDP), accounting for around 18% of GDP as of recent years. This makes it one of the largest contributors to the US economy.
Healthcare is typically considered the largest industry in the US by employment and one of the top industries by economic output, but may not always be the absolute largest when compared to sectors like finance or real estate by GDP. Its size and influence, however, make it a central pillar of the US economy.