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UK Budget 2026: The IFS Puts The Gap At £35bn, The Banks Leave Downing Street None The Wiser, And Gilts Cost The Most Since 1999

On 12 October 2026 the Institute for Fiscal Studies told Chancellor John Healey he needs about £35bn of tax rises or spending cuts at the Budget on 28 October. Six days earlier the UK's biggest banks met him in Downing Street and left without learning whether a windfall tax is coming, and on 29 September the government paid 5.383% to borrow for ten years, the most at an auction since 1999. What the gap is, who pays under each option, and what UK trading and fintech firms should prepare.

AlchmAI Editorial9 min read

£35bn

Tax rises or spending cuts the UK Budget 2026 must find to meet the government's promises (IFS Green Budget, 12 October 2026)

5.383%

Average yield at the 29 September sale of July 2036 gilts, the highest at a 10-year auction since 1999 (Bloomberg)

46.5%

Total tax rate on a model London bank in 2026, against 39.1% in Frankfurt and 27.9% in New York (UK Finance, via The Times)

+0.5%

UK GDP growth in the second quarter of 2026, revised up from 0.4% (ONS, 30 September)

On 12 October 2026 the Institute for Fiscal Studies published its Green Budget and put a number on Chancellor John Healey's problem: about £35bn. That is what the IFS says he must raise in tax or cut from spending at the UK Budget 2026 on 28 October to meet the fiscal rules and still deliver what the government has promised. Sixteen days out, the banks have been summoned and told nothing, and the government pays more to borrow for ten years than at any auction since 1999. For a UK trading or fintech business the question is not who wins the argument. It is what each way of closing the gap costs you.

At the Labour Party conference on 28 September 2026 Healey said "the Prime Minister and I are in lockstep that we will meet the fiscal rules" and that "The money New Labour had in the nineties is simply not there now". The next day the Debt Management Office sold £4.25bn of July 2036 gilts at an average yield of 5.383%. The market heard the promise and still asked to be paid more. We covered the gilt sell-off on 8 October; this article adds the IFS costing, the bank summit and what firms should do.

What Is The £35bn Gap In The UK Budget 2026?

The IFS's director, Helen Miller, was blunt: "A 'steady-as-she-goes' budget is not an option available to the chancellor." On making the sums work on paper alone: "Simply pencilling in implicit cuts that he has no intention of delivering would make the budget a work of fiction." Raising £35bn through tax alone would be equivalent to about three percentage points on every income tax rate, or on the main rate of VAT. One option has reportedly gone: a person familiar with Treasury thinking told Bloomberg that cutting the mansion-tax threshold from £2m to £1.5m is no longer likely after Labour MPs objected. Whatever one thinks of that policy, the retreat means the money has to come from somewhere else.

Why Do Gilt Yields At 1999 Highs Make The Chancellor's Job Harder?

A gilt is a UK government bond and its yield is the interest rate the government pays to borrow. Debt interest counts as day-to-day spending, so every rise in yields eats into the headroom. On 28 September the 10-year yield touched 5.44%; the auction the next day cleared at 5.383% against 5.16% in August, with bids covering the offer 3.34 times, down from more than 3.6. Evelyne Gomez-Liechti of Mizuho said the result "adds to the narrative that investors continue to be reluctant to add duration here despite attractive yield levels." On 1 October the 30-year yield went through 6% for the first time since 1998, and FXStreet reported on 7 October that GBP/USD had traded just above 1.3200 for two weeks.

The economy itself is not stalling. The ONS revised second-quarter growth up to 0.5%, with business investment up 5.2% on the year. Two lines from the Bank of England's Financial Policy Committee record of 30 September matter for 28 October: hedge funds' borrowed positions in gilts, while stable, remain elevated, and sterling bond issuance by AI hyperscalers "accounted for 47% of GBP corporate bond issuance so far this year". The sterling credit market is now, to a striking degree, an AI financing market.

Will Banks Pay For It? Inside The 6 October Downing Street Summit

On 1 October Sky News reported that Healey had summoned the heads of Barclays, HSBC, Lloyds Banking Group and NatWest, amid City fears of bank taxes rising by "billions of pounds a year". Banks already pay a balance-sheet levy and a corporation tax surcharge of 3% on profits above a £100m allowance. Mid-tier lenders asked for the allowance to rise to £500m, and UK Finance warned of "damaging the UK's international competitiveness".

The meeting on 6 October was led by City Minister Lucy Rigby with the Chancellor beside her and lasted just under an hour. According to The Times, Healey was in "listening mode" and said no tax decisions had been made. One person familiar with the discussions summed it up: "Nobody came out any the wiser." Set that against Healey's conference line that "Our financial services, led by London, are some of the best in the world." A Chancellor can admire a sector and still tax it, and the banks know it.

What Are Healey's Options, And Who Pays Under Each?

  1. 01Broad-based tax rises, such as the IFS's three-point illustration on income tax or VAT. Employees, consumers and employers pay. For a London fintech competing for engineers, this reaches payroll first.
  2. 02Targeted taxes on banks and wealth. Bank shareholders pay and, if the mid-tier lenders are right, so do the challenger and specialist banks that provide accounts, safeguarding and lending for much of UK fintech.
  3. 03Spending cuts, real or pencilled in. Users of public services pay, and if the cuts are fictional in Miller's sense, gilt investors price the fiction.
  4. 04Less headroom or looser rules. Everyone who borrows in sterling pays, because the gilt yield is the floor under mortgages, corporate bonds and bank funding.

There is a recent precedent for a Budget-day market reaction. After the Budget of 30 October 2024, the Press Association reported the 10-year gilt yield at 4.568% the next afternoon, its highest since August 2023, with the pound down to $1.2856. ING's Chris Turner called it "nothing like the stress seen under the Liz Truss budget". That says nothing about what 28 October 2026 will bring. It shows the range.

Our View: The Bill Is Real, And A Credible Budget Is The Cheaper Way To Pay It

Our interest is in the consequences for UK trading and fintech firms, not in who holds the Treasury. First, the £35bn is not a forecast of what Healey will do; it is the cost of what the government has already promised, at borrowing costs last seen in 1999. A Budget the market does not believe is the expensive outcome for anyone who borrows or hedges in sterling. Second, the bank-tax debate reaches beyond the banks in the room: every fintech that relies on a mid-tier bank for accounts or safeguarding is exposed to that bank's cost of capital. Third, Budget day is an operational event, in a gilt market with little slack.

“The £35bn is not a prediction of what the Chancellor will do. It is the bill for what the government has already promised, priced at 1999 interest rates.”

What It Means For Trading And Fintech Firms

  • Brokers and CFD providers: treat 28 October as a planned stress day. Agree with your risk committee the margin and position limits for sterling pairs, UK rate contracts and UK bank shares around the statement, staff the desk and client support through the afternoon, and test how the platform handles a gap and a burst of orders.
  • Prop trading firms: make sure the rule engine knows the Budget is a scheduled event. If evaluation rules restrict trading around high-impact news, confirm the 28 October entries and log the rule version in force, so a trader stopped out on a Budget spike can see the tick, the rule and the timestamp.
  • Fintech and trading startups: list which bank holds your safeguarded funds or backs your lending, and ask it before 28 October how a surcharge change would reach your pricing. Run a payroll scenario on the IFS's three-point illustration.
  • Research and quant teams: tag 28 October 2026 as a fiscal event alongside 30 October 2024, store point-in-time data for sterling, the gilt curve and UK bank shares, and note the ONS releases before it: monthly GDP on 15 October, the labour market on 20 October and inflation on 21 October.
  • Compliance leads: keep every client communication about the Budget descriptive. Reporting that the 30-year gilt crossed 6% on 1 October is fine; implying what it will do on 28 October is not.

The Bottom Line

Sixteen days before the UK Budget 2026, the IFS has costed the government's promises at about £35bn against headroom of about £20bn, the banks have been summoned and told nothing, and the government pays 5.383% to borrow for ten years with the 30-year above 6%. Who pays depends on which option Healey chooses on 28 October: taxpayers broadly, banks and the fintechs that depend on them, public services, or everyone who borrows in sterling. For brokers, prop firms, fintechs and quant teams the preparation is the same under every option: set limits, staff the day, log the rules, map the banking exposure and keep the commentary descriptive. AlchmAI, a London trading technology and AI studio, builds the platforms and risk dashboards that make a day like 28 October routine.

References & Further Reading

UK EconomyUK Budget 2026giltsbank surchargeCompliance & Regulatory SystemsAI Agency UKFintech AI Agency LondonInvestment Banking Trading Applications
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AlchmAI Editorial

Research and analysis, London

The AlchmAI team writes about the markets, technology and regulation we work with every day. We build trading platforms, real-time charts and AI analysis tools for brokers, prop firms and fintech teams from our office in Mayfair, London. Every article lists its sources. Nothing we publish is investment advice.

This article is general information and commentary. It is not investment advice or a recommendation to buy or sell any investment. Important information

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