Despite an increase in the gambling tax from 30.5% to 34.2%, income from the levy fell in the first half of 2025, the agency said. It now expects the government to collect around €40 million less than in 2024, missing its target of raising an extra €100 million this year.

The shortfall is partly due to new rules designed to protect players from excessive losses,  Ksa said.

The higher tax is paid by gambling operators, not players, but companies have responded by cutting costs. Spending on advertising fell by 39% in the first quarter of 2025 compared to the same period last year.

The number of physical gambling venues, such as casinos and arcades, also fell by 9% in the first three months of the year compared to the last quarter of 2024.

Online operators have more flexibility to absorb the higher tax rate, Ksa said. Some have adjusted their payout ratios so that a smaller share of each euro wagered is returned to players.

“The measures we have taken to offer players better protection have made it financially more difficult for operators,” said Ksa chairman Michel Groothuizen.

“The Ksa warned before the tax increase was introduced that this would be the outcome. If we want to offer players a safe and regulated environment in future, we need serious, responsible operators. That requires a financially healthy legal market.”

The Ksa said it is unclear whether people are gambling less as a result of the new rules, or turning instead to the illegal market.