Jamie Dimon joins bankers lobbying the UK ahead of its critical budget, here’s why they’re worried

Bankers are piling pressure on the British government ahead of its Autumn Budget, in which the newly minted leadership will lay out its fiscal plans for Britain.

Finance minister John Healey is set to unveil his first budget on Oct. 28. Among the policy shifts reportedly on the table is a windfall tax aimed at banks and oil companies.

JPMorgan Chase CEO Jamie Dimon met with Healey at Downing Street on Wednesday, when he is reported to have also held talks with the U.K.'s new Prime Minister Andy Burnham.

Burnham, who is widely perceived as more left-leaning than his predecessor Keir Starmer, despite being from the same political party, appointed Healey to replace Rachel Reeves as Chancellor of the Exchequer shortly after his ascension to the top job.

The pair are tasked with bringing public spending and borrowing under control, with sticky inflation, elevated government borrowing costs and lackluster economic growth adding to the urgency of balancing the books.

But they have also said easing living costs, devolving political power to local authorities and raising defense spending remain priorities. While the government has identified some savings to help fund its defense plans, Burnham and Healey have yet to spell out the full mix of further savings or tax measures needed to pay for the additional expenditure while sticking to the U.K.'s so-called fiscal rules .

According to British media , Dimon warned the pair on Wednesday against raising the tax burden on banks in next month's budget.

In the U.K., banks already pay the standard 25% corporation tax plus a 3% bank surcharge, an additional bank levy on balance sheets of between 0.05% and 0.1%, as well as general business taxes such as National Insurance on staff wages, sales tax and business rates, a tax on commercial properties like offices. According to trade body UK Finance, the total tax rate figure for banks' U.K. operations in 2025 was 46.4%.

Trade unions and some lawmakers have called for the government to tax banks to a greater degree in the wake of bumper earnings in recent years, which were largely driven by an uptick in net interest income, the difference between the interest earned on assets like loans and the interest paid out on liabilities like customer deposits.

David Postings, the CEO of UK Finance, a trade body representing hundreds of companies operating in British financial services industry, including Goldman Sachs, HSBC , Bank of America and JP Morgan Chase, wrote to Healey last month to express the banking sector's opposition to a windfall tax.

"I am concerned that increasing taxes on banks would ultimately risk undermining the very tax base the government seeks to protect and grow, as well as damaging the UK's international competitiveness," he said in the letter, seen by CNBC.

He also pointed to London's tax rate being notably higher than other global financial hubs, including Frankfurt, Dublin and New York.

Speaking to CNBC's "Squawk Box Europe" on Thursday, Antony Jenkins, founder and CEO, of 10x Banking and former CEO of Barclays , said high taxes "act as a disincentive" for investment and growth.

"We're a world leader in a number of industries: financial services, technologies, creative arts, higher education," he said. "These are industries that we need to be supporting and encouraging to grow, to act as a dynamo for the rest of the economy, so obviously there's a set of very difficult political choices to be made."

He added that the U.K. must avoid creating "a situation in which people think it's a free ride."

"There are no free rides. If you put taxes on industries, that's going to have a consequence," he said.

Dimon himself has also commented publicly on his opposition to higher banking taxes in Britain.

In May, he said JP Morgan may rethink its new 3 million-square-foot tower in London's Canary Wharf financial district if the then-Prime Minister Keir Starmer was replaced by a "hostile" rival. Asked if the political instability gripping Britain changed his view on the mega project in London, Dimon said that if a new government was "hostile to the banks, then yes."

He also told "The Master Investor Podcast with Wilfred Frost" in July that he had "always thought [Britain's taxes on banks] was wrong."

"It may sound great, 'tax the banks', but it's $5 billion that my shareholder's paid on that extra tax," he said. "And I just think things like that have adverse consequences."