 Some cities use "taxi medallions" as permits for taxicab drivers to pick up passengers.Because the medallion system is a government-created intentional constraint on the supply of taxicabs, and historically cities have increased the number of medallions much more slowly than the growth in demand for taxis, medallions have generally been considered a great investment; though recently the increase in supply of cars for hire created by real-time ridesharing companies has been eroding the value of medallions.Taxicab companies may be independently owned small businesses with only one taxicab and driver or have fleets of 100 or more taxicabs.