It's high stakes for UK companies as sports betting starts to spread out in America.

From Tuesday, new rules on wagering entered result in Delaware, a tiny east coast state about 2 hours from Washington.

Neighbouring New Jersey could begin accepting sports bets as early as Friday.

The changes are the very first in what could become a wave of legalisation after the Supreme Court last month cleared the way for states to permit sports wagering.

The industry sees a "once in a generation" opportunity to establish a new market in sports-mad America, said Dublin-based monetary analyst David Jennings, who heads leisure research study at Davy.

For UK companies, which are facing consolidation, increased online competition and harder guidelines from UK regulators, the timing is particularly appropriate.

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But the industry states relying on the US remains a dangerous bet, as UK business face complex state-by-state policy and competitors from entrenched local interests.

"It's something that we're actually focusing on, however equally we do not wish to overhype it," stated James Midmer, spokesman at Paddy Power Betfair, which recently bought the US fantasy sports site FanDuel.

'Take time'

The US accounted for about 23% of the world's $244bn (₤ 182bn) in video gaming earnings in 2015, according to a report by Technavio, external released in January.

Firms are intending to take advantage of more of that activity after last month's decision, which struck down a 1992 federal law that barred states outside of Nevada and a few others from authorising sports betting wagering.

The judgment found the law was an over-reach of federal power. But the court it did not really legalise sports wagering, leaving that question to local lawmakers.

That is expected to result in significant variation in how firms get licensed, where sports wagering can happen, and which occasions are open to speculation - with huge implications for the size of the marketplace.

Potential profits ranges from $4.2 bn to practically $20bn every year depending upon aspects like how many states relocate to legalise, Oxford Economics estimated in a 2017 study for the American Gaming Association.

"There was a lot of 'this is going to be substantial'", stated Will Hawkley, London-based head of leisure for specialists KPMG.

Now, he stated: "I believe many people ... are taking a look at this as, 'it's an opportunity but it's not going to be $20bn and it's going to be state by state and it's going to take some time'."

'Remains to be seen"

Chris Grove, handling director at Eilers & Krejcik Gaming, forecasts that 32 states will legalise sports betting in some kind by 2023, producing a market with about $6bn in annual earnings.

But bookmakers deal with a far various landscape in America than they do in the UK, where wagering shops are a frequent sight.

US laws minimal gambling mostly to Native American lands and Nevada's Las Vegas strip till relatively just recently.

In the popular imagination, sports wagering has actually long been connected to a 1919 baseball World Series match-fixing scandal.

States have likewise been slow to legalise many types of online gambling, in spite of a 2011 Justice Department viewpoint that appeared to eliminate obstacles.

While sports betting is usually seen in its own category, "it clearly remains to be seen whether it gets the type of momentum people believe it will," stated Keith Miller, law professor at Drake University and co-author of a book about sports wagering regulation.

David Carruthers is the former president of BetonSports, who was jailed in the US in 2006 for running an overseas online sportsbook and served jail time.

Now an expert, he states UK companies need to approach the market thoroughly, picking partners with caution and preventing errors that could cause regulator reaction.

"This is a chance for the American sports wagerer ... I'm unsure whether it is a chance for company," he says. "It actually depends on the result of [state] legislation and how business operators pursue the chance."

'It will be collaborations'

As legalisation begins, sports betting companies are lobbying to fend off high tax rates, along with demands by US sports leagues, which want to gather a percentage of revenue as an "integrity cost".

International companies deal with the added challenge of an effective existing gaming market, with gambling establishment operators, state-run lotteries and Native American people that are seeking to safeguard their turf.

Analysts state UK companies will need to strike partnerships, providing their expertise and technology in order to make inroads.

They point to SBTech's recent statement that it is supplying technology for Kentucky Derby operator Churchill Downs as an example of the kind of offers most likely to materialise.

"It will be a win-win for everybody, but it will be collaborations and it will be driven by technology," Mr Hawkley stated.

'It will just depend'

Joe Asher, president at William Hill US, is clear-eyed about the truths.

The company has actually been investing in the US market because 2011, when it bought three US companies to establish an existence in Nevada.

William Hill now employs about 450 individuals in the US and has actually announced collaborations with gambling establishments in Iowa and New Jersey.

It works as threat manager for the Delaware Lottery and has invested millions together with a local developer in a New Jersey horse racing track.

Mr Asher stated William Hill has become a home name in Nevada but that's not always the goal all over.

"We certainly intend to have a very substantial brand existence in New Jersey," he said. "In other states, it will just depend on policy and possibly who our local partner is."

"The US is going to be the greatest sports betting market in the world," he added. "Obviously that's not going to occur on day one."