Inside the Business Model of an Online Casino: Deposits, Bonuses, Games and Margins

A player deposits £100 at an online casino on a Friday night. An hour later it could be £340, or nothing. For the player, that is the whole story. For the operator, it is only the beginning. That £100 passes through a payment processor, compliance checks, a bonus system, a game studio's servers and eventually a tax return, and several other businesses take a cut before the casino books any profit. Following that money is the simplest way to understand how an online casino works.

The examples below use the UK, where the regulator publishes detailed figures, but the same mechanics apply to online casinos everywhere.

Turnover, GGR and NGR

The industry measures itself at three levels.

1. Turnover is the total amount staked. Because winnings get staked again, it can be far larger than what players deposit: a player with £100 who bets £1 a spin for 300 spins has generated £300 of turnover.
2. Gross gaming revenue (GGR), called gross gambling yield (GGY) in Britain, is stakes minus winnings paid out. In other words, it is what players lose in total.
3. Net gaming revenue (NGR) is GGR after deducting bonuses and other incentives. Rank Group, for example, reports this way.

The gap between turnover and GGR is large. Between October and December 2025, Britain's gambling industry took £39.18 billion in stakes and kept £2.12 billion as GGY, about 5.4%. Only around 5p of every £1 wagered was retained.

Even so, the totals are big. Online casino games generated £5.7 billion of GGY in Britain in the year to March 2026, the largest part of a £8.3 billion online market and roughly 15% more than two years earlier. In the US, New Jersey's online casinos took $2.91 billion in 2025, up 22%, overtaking Atlantic City's land-based casinos ($2.89 billion) for the first time.

Deposits are customers' money, not revenue

A deposit is not income. Until it is staked and lost, it belongs to the customer. In March 2026, British online operators held £886.6 million in active customers' accounts. Moving that money costs operators money.

Gambling is classed as a high-risk merchant category, and deposits and withdrawals run through cards, e-wallets and bank transfers. Industry vendors estimate payment processing at 4% to 6% of GGR, and chargebacks and fraud at 0.5% to 2%; these are indicative, not audited, figures. Compliance adds more: operators must verify players' identities, check the source of their funds and watch for signs of harm before paying out. These checks are expensive and slow down sign-up.

Britain has also banned gambling with credit cards since 14 April 2020, after research by the Gambling Commission found credit card users were disproportionately likely to be problem gamblers.

Games: a small edge applied millions of times

Every casino game has a built-in advantage for the house. For slots it is expressed as the return to player (RTP). A slot with 96% RTP is expected to pay back £96 for every £100 staked over millions of spins, a 4% house edge.

Table games build the edge into their rules. European roulette has 37 pockets but pays 35 to 1 on a single number, giving the house an edge of 1/37, or about 2.7%. American roulette adds a double zero, raising the edge to 5.26%. The edge is small; volume does the work.

Back to our player: £100, 300 spins, £300 of turnover. At a 4% edge, the expected loss is £12, not £100. Over millions of spins, big individual wins barely move the totals. That is why slots dominate: they produced £4.8 billion of Britain's £5.7 billion online casino GGY in 2025/26, about 84%. A spin takes seconds, so turnover builds faster than in almost any other game.

Regulation is now limiting that speed. Britain capped online slot stakes at £5 per spin from 9 April 2025, and at £2 for players aged 18 to 24 from 21 May 2025.

Live dealer games, streamed from studios with real dealers, sit between slots and traditional table games. Live game shows in particular are growing in popularity, but live studios are expensive to run.

Bonuses: a real cost, not free money

To players, bonuses can feel like a gift. To operators, they are a cost that comes with conditions, chiefly wagering requirements, which force players to bet the bonus several times before they can withdraw it.

Take a £20 bonus with a 35x wagering requirement: the player must stake £700. At a 4% house edge, the expected loss on that play is £28, more than the £20 bonus. That is how bonuses used to pay for themselves.

Britain has closed that loophole. From January 2026, Gambling Commission rules cap wagering requirements at 10x and ban promotions that mix products, such as casino spins combined with free bets. Many operators had previously used 40x or 50x. Under the new cap, the same £20 bonus needs only £200 of play, an expected loss of £8, so the operator gives away about £12 net. Industry vendors estimate bonus costs at 15% to 25% of GGR, usually the biggest difference between GGR and NGR.

Loyalty points, VIP schemes and retention offers work the same way: a cost now in exchange for a more valuable customer over time.

The cost stack: who else gets paid?

Tax is often the largest cost. From 1 April 2026, Britain's Remote Gaming Duty rose from 21% to 40% of operators' gross gaming profits, and remote sports betting faces a new 25% rate from April 2027. The Office for Budget Responsibility expected operators to pass on about 90% of the increase through lower payouts or higher prices, and forecast the package would raise about £1.1 billion a year by 2029-30, roughly a third less than if players did not change their behaviour.

Game suppliers come next. Studios license their games, often through aggregators, in return for a share of GGR. Vendors estimate platform, content and data fees at 5% to 10% of GGR. Suppliers can be far more profitable than operators: Evolution, the leading live casino studio, reported an adjusted EBITDA margin of 66.1% on €2.07 billion of revenue in 2025.

Marketing and affiliates follow. Affiliate websites are paid either a one-off fee (CPA) for each depositing player or a share of the NGR those players generate. Vendors put typical CPA rates in top markets at $150 to $400, or revenue shares of 25% to 45%. Then come staff, technology, licences and safer gambling teams, largely fixed costs.

Margins: a worked example

The table below is an illustration only, not any company's accounts. It applies the ranges above to a UK operator, per £1,000 of GGR.

The lesson is simple: the house edge is constant, but the margin is not. What matters is how much of the GGR survives the costs. Operators have responded to the tax rise by protecting bonuses where they can and cutting brand advertising, supplier costs and staff. Evoke, owner of William Hill and 888, said the new duties would add £125 million to £135 million a year in costs once fully in force in April 2027, with supplier savings and other medium-term measures, such as shop closures, offsetting about half.

Pressure points

Three forces are reshaping the model:

• Higher taxes reduce what operators keep.
• Player protection rules, such as stake limits and wagering caps, make play less intense.
• The black market, including many crypto casinos, pays no British duty and ignores British rules. The industry argues higher taxes push players towards it; supporters of reform say the evidence is mixed. The government has allocated £26 million over three years to help the Gambling Commission tackle illegal gambling.

The challenge for licensed operators is not demand. It is margin.

Conclusion

An online casino looks like a business of luck, but it is really a business of numbers. The house edge takes a small share of every pound staked; bonuses, tax, suppliers and affiliates decide how much of that survives. For the player, £100 bought an evening's entertainment. For the operator, it meant processing a payment, funding a bonus, paying tax and sharing revenue with a chain of partners. The real skill is not in the games, but in managing everything that happens after the bet.

Sources

1. Rank Group, Q3 2025/26 trading update, 15 April 2026
2. Gambling Commission, Industry Statistics quarterly report, October to December 2025
3. iGaming Business, UK GGY for October to December 2025, including £39.18bn turnover
4. Gambling Commission, Industry Statistics annual report, April 2025 to March 2026
5. iGaming Expert, UK online casino GGY up £736m to £5.7bn
6. New Jersey Division of Gaming Enforcement, December 2025 revenue release
7. NJBIZ, New Jersey gaming revenue record in 2025
8. Track360, GGR vs NGR formulas and industry averages 2026
9. Gambling Commission, credit card gambling ban announcement
10. Gambling Commission, market impact data to June 2025
11. Gambling Commission, consultation response on socially responsible incentives
12. Wiggin LLP, gambling promotions face new regulations
13. GOV.UK, gambling duty changes (tax information and impact note)
14. Intergame, OBR analysis of the 2025 Budget gambling tax changes
15. Evolution, year-end report January to December 2025
16. Track360, affiliate commission rates benchmark 2026
17. Evoke plc, response to the UK Budget, 26 November 2025
18. Hargreaves Lansdown / Sharecast, Evoke withdraws medium-term targets
19. Public Gaming / Yogonet, UK to nearly double online gaming duty