A taxi medallion, also known as a CPNC (Certificate of Public Necessity and Convenience), is a transferable permit allowing a taxicab to operate, particularly in the United States. Several major cities in the US use these in their taxi licensing systems, including New York City, Boston, Chicago, Philadelphia, and San Francisco.
The medallion system is a government-created intentional constraint on the supply of taxicabs, and because cities have historically increased the number of medallions at a slower rate than the growth in demand for taxis, medallions have generally been considered a valuable investment, though recently the increased supply of cars for hire created by ridesharing companies has been eroding the value of medallions.
