NextFin News - Jamie Dimon, chief executive of JPMorgan Chase, has warned UK Prime Minister Andy Burnham that raising taxes on banks could force the world's largest lender to scrap its planned £3 billion headquarters in London, reigniting the battle over whether Britain can afford to tax its most profitable sector.
In a July 16 conversation on the Master Investor Podcast, Dimon said he had not decided whether to proceed with the 3 million-square-foot Canary Wharf tower if the new government increases banking levies. Asked whether he would reverse the decision to build the tower, he said:
"That's a binary decision … I don't know what I would do. I want London to be a happy home for a long time."
The warning lands as the UK's four largest banks report £29.2 billion in profits for the first six months of 2026 — a 21% increase on the same period a year earlier — while campaign groups and trade unions urge Burnham to raise an estimated £19 billion from a windfall tax to fund cost-of-living relief and social care reform.
The timing is delicate. Burnham became prime minister on July 20, replacing Keir Starmer after a Labour Party leadership contest, and his first budget arrives this autumn with John Healey, the former defence secretary, installed as chancellor. Banks now face a government that has declined to rule out higher levies even as lenders argue they are already taxed more heavily than rivals in Frankfurt and New York. The question is no longer whether bank profits are large enough to tax — they are. It is whether London can afford to lose the institutions that generate them.
The Warning and What Is at Stake
Dimon's threat is specific, not rhetorical. JPMorgan gave final approval to build the Canary Wharf tower in November 2025, hours after then-chancellor Rachel Reeves's autumn budget spared banks from the tax increases many in the industry had feared. The building — designed by Rogers Stirk Harbour + Partners, rising 265 metres, and set to become one of the tallest office towers in Europe — would house roughly 12,000 staff, more than half of JPMorgan's 23,000-person UK workforce. The bank estimated the project would add £10 billion to the UK economy over its lifetime, with construction expected to take six years.
That decision was explicitly tied to the tax environment. Dimon told the podcast that the UK government's "priority of economic growth" had been "a critical factor" in the bank's commitment. Now, with a new prime minister and a new fiscal calculus, that commitment is being renegotiated in public. Dimon framed the choice in stark terms:
"I would be very cautious if I was a government thinking that penalising any company out of the ordinary is a good thing for that country. I always thought [the UK bank levy] was wrong. JP Morgan did not damage the UK … We're a great citizen there. We hire people there. We want to be bigger there."
The leverage runs both ways, and that is what makes this a genuine standoff rather than a one-sided threat. For Burnham and Healey, the political arithmetic is compelling: the big four banks — HSBC, Barclays, Lloyds and NatWest — reported £29.2 billion in pre-tax profits in the first half of 2026, with almost half of that, £13.7 billion, already pledged to shareholders through dividends and share buybacks. Campaign group Positive Money estimates a 38% windfall tax on banks' UK profits, in line with the levy on oil and gas companies, would raise £19 billion in 2026. The Trades Union Congress argues that simply reversing the 2023 cut to the bank surcharge would raise £9 billion over four years.
For the City, the arithmetic cuts the other way. UK banks already pay a 28% corporation tax rate, higher than the standard 25%, plus a separate surcharge of 3% and a levy on their UK balance sheets. When employment taxes and VAT are included, the sector's total tax rate reaches about 46.4%, according to UK Finance — compared with 38.9% in Frankfurt and 27.9% in New York. The bank surcharge alone raised roughly £1 billion for the Treasury in the most recent period. The industry's argument is not that it cannot pay; it is that every additional pound extracted makes London marginally less competitive, and that marginal decisions compound into capital flight.
Why Bank Profits Became the Target
The profit surge is real, and it is not subtle. HSBC reported £14.5 billion in pre-tax profit for the first half of 2026; Barclays, Lloyds and NatWest added £6.1 billion, £4.3 billion and £4.3 billion respectively. Profits broke records in 2023 and 2024 and came close again in 2025. The driver is mechanical rather than entrepreneurial: higher interest rates, set by the Bank of England to fight inflation, widened the spread banks earn on deposits and loans. The same rates also mean the central bank pays tens of billions each year to commercial banks on reserves — a cost ultimately borne by the Treasury.
This is the core of the moral case for a windfall tax. When the state raises rates to cool the economy, households and small businesses pay more to borrow, and that money flows to banks not because they built better products but because monetary policy made money more expensive. Positive Money's analysis argues the tax should target only profits made from UK retail banking, not investment-banking activity, precisely to blunt the competitiveness objection: a tax on domestic retail margins would not, in its design, give banks an incentive to move trading desks overseas.
But the cyclical nature of the profit wave matters for policy design, and it is the point the tax advocates least want to confront. If profits are high because rates are high, they will fall when rates fall. A windfall tax calibrated to today's margins risks taxing a peak that will not persist — or, worse, locking in a rate that bites hardest when the cycle turns. That is the classic error of windfall taxation: it arrives when profits look obscene and stays when they look normal. The 21% year-on-year profit growth that makes taxation so tempting today is the same number that will look very different in a lower-rate environment.
The Competitiveness Question: Cyclical Profits, Structural Weakness
Here the analysis needs to separate two things that Burnham's government is tempted to conflate. The profit surge is cyclical — rate-driven, mean-reverting, temporary. The competitiveness problem is structural — a regime condition that will not fix itself when rates fall. Confusing the two produces bad policy: taxing cyclical profits as if they were permanent, while treating a structural erosion as if it could be wished away.
London's position as a global financial center has been eroding for reasons that have nothing to do with this year's tax rate. Companies have been delisting from London in rising numbers; the UK equity market has lost depth relative to New York; Brexit removed frictionless access to the European Union; and regulatory burden has accumulated layer on layer. Dimon pointed to the delisting trend explicitly as "another potential challenge for the country's capital markets." These are not cyclical fluctuations. They are the slow draining of a pool that took centuries to fill.
The transmission mechanism from tax to capital flight is not dramatic. It is marginal. No chief executive wakes up and moves 12,000 jobs because a surcharge rises by a percentage point. What happens instead is that the next expansion goes elsewhere, the next listing goes to Amsterdam or New York, the next trading desk sits in Paris. Each decision is rational on its own terms, defensible in a board memo, and individually small. Collectively, they are how financial centers lose their status — not with a collapse but with a thousand small departures. This is why Dimon's warning deserves to be taken seriously even by those who doubt he would actually cancel the tower: the tower is the visible symbol, but the real risk is invisible, scattered across hundreds of decisions that never make headlines.
Dimon's own history illustrates the mechanism. He has objected to the UK bank levy for years, saying in a May 2026 interview: "We paid probably $10 billion extra taxes by now. I don't think that's right or fair." Yet JPMorgan stayed, and in November 2025 it committed to the largest single office investment in Canary Wharf's history. The point is not that banks leave at the first sign of higher taxes. It is that each tax decision is a data point in a long-running assessment of where capital is welcome — and London has been sending mixed signals to capital for a decade.
The Counter-Thesis: Why a Tax Hike Might Not Cost London
The strongest argument against Dimon's warning is that it has been made before, and London has not collapsed. The bank levy was introduced by the Conservative government in 2011, raised repeatedly, scaled back after industry protests, and cut again in 2023 — and the City remained Europe's largest financial center throughout. HSBC, which threatened to leave London repeatedly during the levy debates, stayed; then-chancellor George Osborne scaled the levy back to UK-only balance sheets in 2014 precisely to keep it from doing so. The pattern suggests banks talk loudly about exit and move rarely, because London offers something taxes cannot easily replicate: deep capital markets, a common-law system, a time-zone bridge between Asia and America, and a concentration of talent that no single tax decision dislodges.
There is also a distributional argument that the government cannot ignore. When households are struggling with living costs and the public finances are constrained, taxing a sector that earned £29.2 billion in six months and returned £13.7 billion to shareholders is politically rational even if it is economically suboptimal. Paul Nowak, general secretary of the TUC, put the distributional case plainly:
"Banks can easily afford to pay more tax. This is a chance for the new prime minister and chancellor to show whose side they're on."
A government elected to redistribute has limited patience for warnings from the beneficiaries of the status quo.
And the design matters. Positive Money's proposal — a 38% levy on UK retail-banking profits only — is built specifically to answer the competitiveness objection. If the tax targets domestic margins rather than global trading activity, the incentive to relocate operations is materially reduced. The counter-thesis, in short, is that a narrow, well-designed tax can raise revenue without triggering exodus, and that Dimon's warning is bargaining posture as much as economic analysis.
That counter-thesis is serious, and it is why this is a genuine dilemma rather than a simple case of corporate pressure. But it rests on an assumption that deserves scrutiny: that banks distinguish cleanly between retail and investment activity when deciding where to locate. In practice, the two are bundled. Trading desks need deposit franchises; investment banks need commercial relationships. A tax that formally targets retail profits still raises the total cost of doing business in London, and total cost is what matters at the margin. The rebuttal to the counter-thesis, then, is not that a tax hike guarantees capital flight, but that it adds weight to a scale that has been tipping away from London for years.
What to Watch
The decisive signal will come in Burnham and Healey's first budget, expected this autumn. If the government raises the bank surcharge or introduces a broad windfall levy, the market's reaction will be the first read on credibility: a selloff in UK bank shares and a widening of the tax wedge versus Frankfurt would confirm that investors price London as a higher-risk jurisdiction. If the government instead narrows any levy to domestic retail profits and pairs it with growth measures, the damage can be contained.
Specific metrics to watch: the UK bank surcharge rate, currently 3% above the 25% corporation tax rate; the big four banks' full-year 2026 profit figures, due early 2027; the number of UK equity delistings and new listings through 2026; and, most concretely, JPMorgan's own capital-expenditure guidance for the Canary Wharf project. If JPMorgan formally pauses or cancels the tower, the warning will have moved from rhetoric to consequence.
The falsifying signal for the competitiveness thesis is equally concrete. If, after a tax increase, London's share of European financial-services activity holds steady and no major lender relocates material operations over the following 24 months, then Dimon's warning was bargaining leverage rather than a genuine threat. If one major global bank announces a material relocation of jobs or balance sheet out of London within 18 months of a tax hike, the structural-erosion thesis is confirmed.
The Bottom Line
This is a choice between two kinds of money. The government can raise £19 billion now — real money, for real needs — or it can preserve the conditions that generate far more than that over decades. The profit numbers make taxation tempting; the competitiveness data makes it dangerous. Burnham's budget will reveal which time horizon his government actually operates on.
The short-term view says tax the windfall: profits are cyclical, public need is urgent, and banks will stay because London is irreplaceable. The medium-term view says design narrowly: target retail margins, spare global activity, and pair any levy with growth measures. The long-term view says the question is not how much revenue a tax raises but what it signals — and London has been signaling uncertainty to capital for long enough. A financial center is not taxed; it is courted. Once that truth is forgotten, the bill arrives quietly, in delistings and departed desks, long before anyone notices the center has moved.
Dimon's warning should be read not as a threat about one building, but as a referendum on whether London still understands what makes a financial center work. The answer will not come from a press conference. It will come from the thousand small decisions that capital makes when it thinks no one is watching.
Explore more exclusive insights at nextfin.ai.
