United States - Illinois

Illinois is the cautionary tale of US sports betting taxation, and an operator has to read it as a margin problem before anything else. The Illinois Gaming Board oversees a legal online sports betting market, but online casino is not legal, so this is a sports-only state. What makes Illinois distinctive is not the product set but the cost of operating in it, because the state has built the most punitive tax and fee structure in the country. Any operator modelling Illinois on the economics of a normal sports state is modelling the wrong market.

The tax structure is the most hostile in the US. Illinois moved off a flat 15% rate to a graduated 20 to 40% tax on adjusted gross receipts, with the largest operators paying most of their revenue at or near the 40% top bracket. That alone reshapes the economics, but it is only half the story. The real differentiator is the per-wager fee.

The per-bet fee changed operator behaviour overnight. Effective 1 July 2025, Illinois added a first-of-its-kind transaction fee of $0.25 on each of the first 20 million bets a year and $0.50 on every bet after that. The major operators responded by passing it straight to players: from September 2025, FanDuel and DraftKings each added a $0.25 surcharge per online bet. The effect was a roughly 15% drop in bet count year on year, steepening toward 25% into early 2026, even as dollar handle largely held up. The fee punishes high-volume, low-stake models, micro-bets and parlays most, which is precisely where engagement and margin concentrate.

What this means for an entrant. Illinois is a structurally hostile cost base, and a new entrant competing against operators who are already surcharging players faces the worst of both worlds: a 40% marginal tax and a per-bet fee that makes the highest-engagement products uneconomic. The handle is large and the population is attractive, but the unit economics are among the hardest in the country, and there is no online casino to cross-sell into to rescue them.

What winning looks like. Winning in Illinois looks like a disciplined, efficiency-led sports operation that models the 40% bracket and the per-bet fee from day one, avoids chasing low-stake volume that the fee makes uneconomic, and competes on product and brand rather than on a promotional war it cannot fund at this tax. The operators who survive treat Illinois as a market to be run tightly rather than scaled aggressively. The mechanics of building a sustainable book under pressure are covered in the how to grow a sportsbook piece.

The regional play. Illinois sits in the US cluster alongside the iGaming states of New Jersey, Pennsylvania and Michigan, where online casino lifts the economics that a sports-only state like Illinois cannot. For most operators the efficient path is to build the US model in the iGaming states and treat Illinois as a high-tax sports market entered selectively. The broader logic is in the multi-market sequencing piece, and an online casino opening in Illinois, repeatedly proposed and so far stalled, would change the calculus entirely.

The biggest mistake. The biggest mistake is entering Illinois with a high-volume, low-stake acquisition model into a per-bet-fee regime that taxes exactly that behaviour. The related mistake is modelling the market on a normal sports-state tax rather than the 40% bracket plus the fee. Build for the hostile cost base specifically, run for efficiency rather than volume, and recognise that Illinois rewards discipline and punishes the spend-led playbook that works in lighter states.