Nevada’s Gaming Control Board issued a notice yesterday saying the sites must stop offering their contests to Nevada residents immediately. Operators face fines and 10 years in prison.
The move increases tensions between US states and the games firms which are engaged in a growing dispute over their status as “games of skill” under which they are currently able to operate within the law.
The two leading players in the sector already avoid some states which have made known their objections to what some regard as no different to online gambling which is banned under Federal law.
One television station has banned adverts from Edinburgh and New York based FanDuel, run by chief executive Nigel Eccles (pictured speaking recently in Edinburgh).
The FBI has now been called in to investigate following concerns raised by regulators and Congress.
The sites were drawn into further controversy when it was alleged that an employee of DraftKings used inside information to win $350,000 playing on FanDuel. Both firms deny wrongdoing but they have banned their employees from playing the games.
Customers pick daily lineups of players in professional football, basketball, hockey and other leading US sports, and compete with other players to earn the most points and play to win big money prizes. FanDuel pays out $2 billion a year in prize money.