Ladbrokes owner Entain Plc said on Wednesday that its UK & Ireland online business would incur annualised additional costs of around £200m from the changes to gambling taxes announced in the Budget.
In her long-awaited Budget, Chancellor Reeves announced a number of changes that are expected to raise £1.1bn by 2029-30.
From April 2026, there will be an increase in remote gaming duty from 21% to 40% and the abolition of bingo duty from its current 10% rate.
Reeves also said that from April 2027, a new rate of general betting duty for remote betting will be introduced at 25%. This will exclude self-service betting terminals, spread betting, pool bets, and horseracing.
The government also announced a freeze in casino gaming duty bands in 2026-27, with the usual retail price index uprating thereafter.
In a statement after the close of UK markets, Entain said it was "disappointed" by the tax increases announced.
"Aligned with the Betting & Gaming Council (BGC), Entain strongly believes that maintaining well-balanced regulatory frameworks alongside proportionate tax regimes are critical to protecting customers and supporting the sector," it said.
It said Wednesday's changes fail to deliver this balance and will see regulated operators limited to providing a "less attractive and lower quality" customer offering compared to the unlicensed and untaxed black market.
"These disproportionate tax increases will have a detrimental impact on the economic contribution of the gambling industry, put jobs at risk, reduce funding for sports, and benefit the black market," it said.
The additional £200m in costs was put down to the change in the RGD and the introduction of a new general betting duty for remote betting.
Entain expects to mitigate about 25% of the impact through actions including reducing marketing and promotions, beginning immediately, alongside the implementation of the tax changes.
"Therefore, consistent with the dates of proposed implementation, this equates to an EBITDA impact of approximately £100m in 2026 (8% of consensus FY26 EBITDA) and approximately £150m from 2027," it said.
Chief executive Stella David said: "Disproportionately increasing gambling taxes will not only have a detrimental impact on our industry but also heightens the risk for customers. As seen in other countries, punitive tax increases often lead to lower tax revenues overall, whilst also driving players to illegal, unregulated operators with no player protections. The Government must now urgently tackle the black market and the consequences of today's decision.
"Entain remains well positioned to deliver sustainable growth, underpinned by the group's diverse geographic footprint and strong portfolio of leading positions in attractive markets."
The shares ended up 5% at 784.10p, having tumbled in the aftermath of the Office For Budget Responsibility's leak.