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

From Tuesday, brand-new guidelines on betting came into effect in Delaware, a tiny east coast state about 2 hours from Washington.

Neighbouring New Jersey might start accepting sports bets as early as Friday.

The modifications are the first in what could end up being a wave of legalisation after the Supreme Court last month cleared the method for states to enable sports wagering.

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

For UK firms, which are coming to grips with debt consolidation, increased online competitors and harder rules from UK regulators, the timing is particularly appropriate.

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But the industry says depending on the US remains a dangerous bet, as UK business deal with complex state-by-state policy and competition from entrenched regional interests.

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

'Take time'

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

Firms are wanting to use more of that activity after last month's choice, which struck down a 1992 federal law that barred states beyond Nevada and a couple of others from authorising sports betting.

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

That is anticipated to lead to significant variation in how firms get certified, where sports betting can take place, and which events are open to speculation - with huge ramifications for the size of the market.

Potential profits ranges from $4.2 bn to nearly $20bn yearly depending on factors like how many states move to legalise, Oxford Economics approximated in a 2017 study for the American Gaming Association.

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

Now, he said: "I believe many people ... are looking 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 require time'."

'Remains to be seen"

Chris Grove, managing director at Eilers & Krejcik Gaming, forecasts that 32 states will legalise sports betting wagering in some form by 2023, creating a market with about $6bn in annual profits.

But bookmakers face a far different landscape in America than they do in the UK, where betting stores are a regular sight.

US laws limited betting largely to Native American lands and Nevada's Las Vegas strip until relatively just recently.

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

States have also been slow to legalise many kinds of online gambling, despite a 2011 Justice Department viewpoint that appeared to remove challenges.

While sports betting is usually seen in its own classification, "it clearly stays to be seen whether it gets the type of momentum people think it will," said Keith Miller, law professor at Drake University and co-author of a book about sports betting guideline.

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

Now a specialist, he says UK companies should approach the marketplace carefully, choosing partners with care and avoiding errors that might cause regulator backlash.

"This is an opportunity for the American sports wagerer ... I'm not sure whether it is an opportunity for business," he states. "It truly is dependent on the result of [state] legislation and how the business operators pursue the opportunity."

'It will be partnerships'

As legalisation begins, sports betting companies are lobbying to ward off high tax rates, in addition to requests by US sports leagues, which wish to gather a percentage of revenue as an "stability fee".

International business face the included difficulty of a powerful existing gaming market, with casino operators, state-run lottery games and Native American tribes that are seeking to protect their grass.

Analysts say UK firms will need to strike collaborations, offering their proficiency and technology in order to make inroads.

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

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

'It will just depend'

Joe Asher, primary executive at William Hill US, is clear-eyed about the realities.

The company has been buying the US market because 2011, when it bought three US firms to develop a presence in Nevada.

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

It works as danger supervisor for the Delaware Lottery and has invested millions along with a local designer in a New Jersey horse racing track.

Mr Asher stated William Hill has become a household name in Nevada however that's not necessarily the goal everywhere.

"We certainly intend to have an extremely considerable brand name existence in New Jersey," he said. "In other states, it will just depend on policy and possibly who our regional partner is."

"The US is going to be the most significant sports wagering market in the world," he added. "Obviously that's not going to occur on the first day."