If the casino industry gets its way, this could be the last March Madness where Americans have to go to Nevada to bet legally on the college basketball championship.

The U.S. Supreme Court is expected to rule, possibly next month, on New Jersey's bid to offer sports betting. If the court gives the go-ahead, it could start a chain reaction of states approving such wagers in casinos and online. Forecasters see revenue from legal sports betting rising to the billions of dollars within five years, while companies including MGM Resorts International and Caesars Entertainment Corp. are closely watching the case.

"They're all just sort of circling around the opportunity and getting ready to pounce," said David Henwood, an analyst with the U.K.-based researcher H2 Gambling Capital.

Federal law limits sports betting to the states that offered it before legislation was passed in 1992: Nevada, Montana, Delaware and Oregon. Of those, only Nevada offers a full suite of betting options, including college hoops. Oregon no longer offers it.

Read more: QuickTake on sports betting

Sports leagues have historically opposed expanded betting, but sentiment seems to be shifting. The National Basketball Association has been asking for a cut, a 1 percent "integrity fee," if such wagering is allowed. Five states have passed legislation and may be in position to offers sports betting soon after Supreme Court approval, according to Gambling Compliance, a Washington-based industry researcher. They are New York, Pennsylvania, New Jersey, Mississippi and West Virginia.

Nevada, with a long history of sports betting, provides a window into what the rest of the country could look like. Marco D'Angelo, a professional gambler who sells sports picks in Las Vegas, has six apps on his smartphone. Just like a Wall Street trader, he can check the odds at establishments in the state. If MGM has a more favorable point spread on a particular game than the Golden Nugget, he no longer has to race between the properties to place his wager.

"It's just like shopping online," D'Angelo said.

Nevada Parlors
Nevada betting parlors also allow wagering while a game is being played. So if the team D'Angelo already bet to win is losing, he can gamble on a different outcome and perhaps recoup his money. Another type of wager, called a proposition bet, lets customers put money on outcomes other than the winning team, such as who the most valuable player will be. "A lot of times you find value in the game," D'Angelo said.

Fans at University of Nevada basketball games or Golden Knights hockey games, for example, can be seen whipping out their phones to place bets. Last month, Super Bowl betting hit an all-time high, a 15 percent increase from the prior year. The college basketball championships, which began Tuesday, could see a similar bump.

The most likely winners from a favorable court decision will be existing operators -- casinos, horse tracks and lotteries. Many, and their suppliers, are already getting in position.

In January, Scientific Games Corp., a major slot machine maker completed the $631 million acquisition of NYX Gaming Group, the largest provider of software for sports betting globally. William Hill Plc, the London-based betting parlor operator, is already the leading player in Nevada and has built a sports book at Monmouth Park Racetrack in New Jersey in anticipation of legalization. Last month, Churchill Downs Inc. acquired a casino in Erie, Pennsylvania, for $179 million in part to take advantage of the legislation there.

Following a favorable court decision, states that have authorized sports betting will have to set up their own rules. Others, like California, will have to weigh whether to let their existing operators expand into sports betting. Few in the industry see a strong chance for federal legislation that would legalize sports betting across the country.

In Nevada, sports betting is limited to people physically present in the state, such as residents and tourists. Software built into betting apps prevents people who are elsewhere from playing. Money also has to be deposited in person at casinos or other establishments, even for online wagering.

Choosing Partners
Many casino operators may choose to partner with companies that specialize in sports betting, particularly those with experience in Europe, where it's been legal for decades.

International Game Technology, which makes slot machines and runs state lotteries, launched its first sports betting product in Italy in 2007, according to Renato Ascoli, CEO of the company's North American operations. Last year, MGM began using IGT's software in Nevada.

Other operators with experience in Europe who are now eyeing U.S. expansion include Ladbrokes Coral Group Plc, Paddy Power Betfair Plc and Toronto-based Stars Group Inc., the parent of the PokerStars website.

Depending on how legislation or rules are written, there may be opportunities for other operators to enter the business, whether they be daily fantasy sports sites such as FanDuel Inc. or a new player, like Verizon Communications Inc.

Relative to other forms of betting, the share of bets kept by sports books is low, only about 5 percent, compared with 15 percent for blackjack, roulette or craps. The risk of a big-game upset is high, which is why casinos often partner with companies that specialize in sports betting.

"There's no other part of our portfolio where you can potentially lose money," IGT's Ascoli said.

— With assistance by Greg Stohr, and Eben Novy-Williams

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