Shares of casino companies soared after the U.S. Supreme Court struck down a federal law that bars gambling on individual sporting events, opening up a new source of revenue for the industry.

Scientific Games Corp., Boyd Gaming Corp., MGM Resorts International and Caesars Entertainment Corp. all rose in the wake of the decision. Other companies, such as online gaming giant Stars Group Inc. and International Speedway Corp., also climbed.

The rally follows a decision that found a 1992 law unconstitutionally forced states to maintain rules that outlaw gambling. Nevada is the only state where single-game wagering is now legal. Sports gambling could begin in a matter of weeks in casinos and racetracks in New Jersey, which instigated the legal fight by repealing its gambling prohibition.

Scientific Games, a slot-machine maker that also processes bets for sports-book operators, saw its shares climb as much as 11 percent. Caesars, the largest operator of casinos in the U.S., rose 7.1 per cent. Also gaining: a group of non-U.S. betting parlor and online operators that have already been taking wagers on sports in other countries.

William Hill Plc, one of the largest betting-shop operators in the U.K., saw its shares pop 9.6 per cent. William Hill already has the largest number of sports books in Nevada. Stars, a Canadian company that owns the PokerStars brand, saw a 15 per cent gain.

MGM, the largest owner of casinos on the Las Vegas Strip, saw its shares as much as 3.5 per cent. The company gave a presentation to investors last week in week in which it sketched out a future of more professional sports teams in Las Vegas and a greater presence nationally in sports betting, either online or in casinos.

“We believe in the next two years to three years, there are 10 to 12 states that are ripe and ready to activate on that,” MGM President William Hornbuckle said. “We will be there. We will participate in it. We bring technology. We bring knowledge. And frankly in this space, we bring trust.”