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

From Tuesday, brand-new guidelines on wagering came into result in Delaware, a tiny east coast state about two hours from Washington.

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

The changes are the first in what might end up being a wave of legalisation after the Supreme Court last month cleared the way for states to allow sports wagering.

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

For UK firms, which are facing consolidation, increased online competition and tougher rules from UK regulators, the timing is particularly opportune.

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But the market says depending on the US remains a risky bet, as UK companies deal with complicated state-by-state policy and competitors from established local interests.

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

'Take some time'

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

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

The judgment discovered the law was an over-reach of federal power. But the court it did not actually legalise sports wagering, leaving that concern to regional legislators.

That is expected to lead to considerable variation in how firms get accredited, where sports wagering can happen, and which events are open to speculation - with huge ramifications for the size of the market.

Potential income ranges from $4.2 bn to almost $20bn annually depending on factors like the number of states transfer to legalise, Oxford Economics approximated in a 2017 research study for the American Gaming Association.

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

Now, he stated: "I think most individuals ... are taking a look at this as, 'it's a chance however 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, predicts that 32 states will legalise sports wagering in some form by 2023, creating a market with about $6bn in annual earnings.

But bookmakers face a far various landscape in America than they perform in the UK, where betting stores are a frequent sight.

US laws restricted gambling mostly to Native American lands and Nevada's Las Vegas strip up until relatively recently.

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

States have also been slow to legalise numerous forms of online betting, in spite of a 2011 Justice Department viewpoint that appeared to eliminate barriers.

While sports betting is typically seen in its own category, "it clearly remains to be seen whether it gets the sort of momentum individuals believe it will," stated Keith Miller, law teacher at Drake University and co-author of a book about sports wagering policy.

David Carruthers is the former primary executive of BetonSports, who was detained in the US in 2006 for running an offshore online sportsbook and served jail time.

Now a consultant, he says UK firms should approach the market thoroughly, selecting partners with care and avoiding mistakes that might lead to regulator backlash.

"This is a chance for the American sports gambler ... I'm not sure whether it is an opportunity for organization," he says. "It actually depends on the result of [state] legislation and how the organization operators pursue the chance."

'It will be partnerships'

As legalisation starts, sports betting companies are lobbying to fend off high tax rates, in addition to demands by US sports leagues, which desire to gather a portion of income as an "stability fee".

International companies deal with the added difficulty of a powerful existing gaming market, with casino operators, state-run lottos and Native American tribes that are seeking to protect their turf.

Analysts say UK firms will need to strike partnerships, offering their know-how and technology in order to make inroads.

They point to SBTech's recent announcement that it is providing 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, however it will be collaborations and it will be driven by innovation," Mr Hawkley said.

'It will simply depend'

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

The business has actually been buying the US market considering that 2011, when it acquired three US companies to develop a presence in Nevada.

William Hill now uses about 450 people in the US and has actually announced collaborations with casinos in Iowa and New Jersey.

It works as risk manager for the Delaware Lottery and has actually invested millions alongside a regional designer in a New Jersey horse racing track.

Mr Asher stated William Hill has become a home name in Nevada but that's not necessarily the objective everywhere.

"We certainly mean to have a very substantial brand name presence in New Jersey," he said. "In other states, it will simply depend upon regulation and potentially who our regional partner is."

"The US is going to be the most significant sports wagering market worldwide," he included. "Obviously that's not going to happen on the first day."