In the United States, the jock tax is the colloquially named income tax levied against visitors to a city or state who earn money in that jurisdiction. Since a state cannot afford to track the many individuals who do business on an itinerant basis, the ones targeted are usually very wealthy and high profile, namely professional athletes. Not only are the working schedules of famous sports players public, so are their salaries. The state can compute and collect the amount with very little investment of time and effort.