英国予算、2026年10月28日：波乱のない予算が予想されるが、反応リスクはマイナス方向に偏る

The government has positioned this to be an uneventful budget, and the reaction should follow, though risks are skewed to a negative response if Healey disappoints. Headroom likely to settle around GBP 15bln (prev. 23.6bln) after the hit from energy, yields and rate expectations, while manifesto pledges and a pro-business approach limit the levers. Bank surcharge likely the main revenue raiser; energy and defence spending the primary unknowns. DMO remit seen modestly higher, long-end share to be cut once again, which could partly offset a poorly-received speech. OVERVIEW Potentially, set to be a relatively uneventful budget, as much of the unknowns have been clarified ahead of time, and as the Chancellor is set to meet the fiscal rules, which apply to 2029-30 for this event; rolls from April. The main outstanding points are: the final headroom level, somewhere around GBP 15bln; defence spending, expected to see “billions” announced, according to The Times; size of the bank tax, surcharge to at-most increase from 3% to 8%, raising GBP 2bln; Rosebank decision, following Jackdaw’s green light, is expected to be in 2026, weekend reports suggest the Chancellor is in favour; energy & cost of living, expectations on the cost of this vary extensively, and are (alongside defence spending) the main expenditure unknown, recent reports suggest a “green tax” in imported energy is under consideration. For taxation, the unknowns are the smaller levers the government can pull, such as the NIC base and whether pensioners are included or not, raising GBP 2-4bln, while CGT is not expected to be touched significantly, a smaller tweak or an exit/death-clause could raise a few billion each. Fresh sin-taxes are always a possibility, alongside measures to property, given the offsetting policy of Your First Home. Finally, PM Burnham has pledged to adjust the triple lock from 2030 to fund a NCS, though the adjustment falls outside the 2029-30 target year, and thus is largely moot. One of the big unknowns that the government can’t directly control is wages. The National Living Wage is provisionally expected to increase by 3.7%, but risks are very much skewed to the upside, lifting tax receipts and thus bolstering headroom, potentially with taxation thresholds frozen. Further, the average earnings growth view for 2027 should be revised higher from the Spring 2.4% view, potentially by as much as 60bps. However, it adds significantly to departmental pressures, though any change is likely to be deferred to the 2027 Spending Review, and is a factor of the triple-lock. Overall, wages present one of the most probable positive surprises for the headroom figure, as the benefit will be immediately present in the forecasts, while the departmental and other costs will be deferred or not counted. Upside that could offset much of the hit from higher yields to the Spring GBP 23.6bln headroom, and current assessments of around GBP 10-12bln. For the market, if everything is roughly as touted in the press and there are no major surprises to the above points, then the reaction should be relatively muted. Unless, the headroom does not increase from the current assumed GBP 10-12bln area, and if the tough choices are pushed back too far, a decision that has two detrimental impacts on UK assets: 1) a lack of fiscal credibility; 2) chimes with the 2027 Spending Review, but arguably the clearest signal yet that PM Burnham is thinking of an early election. Though, another cut to long-end issuance could be sufficient to offset some of the reaction to this, for the near term at least. Finally, the DMO remit is expected to increase for 2026-27. The Gross Financing Requirement (GFR) is seen increasing by GBP 8-15bln (prev. 268bln), with Gilt sales up by GBP 0-10bln, from the current GBP 246.2bln. Once again, the long-end share is likely to be reduced, though there is no firm consensus on the magnitude of any adjustment. DMO Currently, as of the April revision, the Net Financing Requirement (NFR) for 2026-27 was forecast at GBP 251.2bln, (GFR at 268bln, for reference), featuring Gilt sales of GBP 246.2bln, with 9.1% from long, 30.9% medium and 38.6% short. The GFR was then projected to increase to GBP 307.6bln for 2027-28, before then dropping down in the following years to GBP 211bln by 2030-31. The remit is expected to increase for 2026-27. GFR and NFR are both seen higher by around GBP 8-15bln, with most views holding around the GBP 10bln mark. In terms of issuance, total Gilt sales are expected to increase by as much as GBP 10bln, but the consensus lies around the GBP 3.4bln figure. For the breakdown, long-end <7% (prev. 9%) and at the lowest share in over 35yrs, medium to tick up by around 4pp from 31%, short-end by around 3pp from 39%, while T-bills are to double in size from GBP 5bln to GBP 10bln. Another skew away from the long-end that is merited by yields in that bracket, 20yr+, continuing to lift and residing at multi-decade highs. Additionally, the shift is seen in DMO activity for the current FY, as there has only been one long-end sale despite over half of the year having passed, and while one has been announced for November and another three expected thereafter, this cadence could well be cut. If the long-end is cut as expected, this may be enough to shore up any fiscal slippage concerns from the Chancellor not taking action on the main spending concerns. As a reminder, much of the move on the last budget was driven by the DMO issuance skew away from the long-end. OBR Forecasts The forecast window is, usually, done over two weeks around five weeks before the budget announcement, equating to a 25th September cut off. Meaning the 10yr yield assumption is roughly where it is now, at about 5.36%; however, the 20yr and 30yr yield are now about 6-8bps higher. Note, this is not a fixed rule, but is an established convention. The final data inputs typically end the week before, so it should include the recent CPI (hot), Employment (hawkish) and PSNB, which FY YTD is 6bln above the OBRs view. For the headroom, the below forecasts and expected policies mean an eventual headroom of around GBP 15bln vs the previous forecast of GBP 23.6bln and a pre-budget assumed starting point of GBP 10-12bln, mainly due to higher yields, inflation and BoE Bank Rate expectations. Forecast OBR March (or as applicable) Expectation Headroom Impact UK Yields 10yr 4.5%, 30yr 5.3%. Yields across the UK curve are over 50bps higher, based on the period to 25th September. -6bln hit to headroom, though the exact figure depends on the precise forecast period. BoE Pricing Bank Rate to average 3.6% to 2030. Currently, markets price in excess of 100bps of tightening over the horizon, though a number of desks believe this is excessive. -4bln or so to headroom. CPI/RPI (Y/Y) CPI 2026: 2.3%, 2027-30: 2.0%. RPI Jan’2027: 3.0% Likely to be revised higher, to over 3% for 2026 & 2027. Before then moving back towards/to the 2.0% mark for 2028. RPI also to be lifted, to over 5% for January 2027. Several billion hit to headroom, though the exact figure is very dependent on the specific forecasts. Wages (Y/Y) 2027: 2.4%. 2028: 2.1%. Significant upgrade expected to the 2027 view, of 30-60bps. Net lift to headroom of around 5-10bln from tax receipts, some modest offsetting influence from departmental spending and other points. Real GDP (Y/Y) 2026: 1.1%, 2027: 1.6%, 2028: 1.6% Near-term growth performance has been better than forecast, but the trajectory will likely see a modest downgrade. -2bln or so hit, very dependent on the final forecast. BoE QT 65bln/yr average, 32bln of active sales. BoE has reduced activity. Net zero, lower action but at a higher rate. Net Migration 235k/yr Current ONS view is 171k, Expected to be downgraded. Every 50k downgrade hits headroom by around 4bln; based on one OBR projection of 200k lower, means 13-20bln of additional borrowing. Planning Reform 3.4bln less borrowing. Current housebuilding plans are set to be revised, potentially removing the favourable 3.4bln assessment. However, the Your First Home scheme may offset this, depending on how it is scored. Likely negative to headroom. BOE The BoE is expected to begin its tightening cycle in November. Unless the budget is deemed as not fiscally credible, or similar, to an extent that a bond rout occurs, making it difficult and unwise for the BoE to tighten financial conditions further, given the potential growth implications of such a scenario. Nonetheless, the expected measures would theoretically give a small uplift to growth and a modest cut to inflation, but not to a degree to prevent a hike this year. However, it may add to the narrative that market pricing around the BoE by end-2027 is overdone, and could pare some of this, though a significant move is unlikely until after the November BoE. TAXATION Measure Likelihood Outcome (GBP) Bank Surcharge High Returning to 8% from 3%, raising 2bln, with each pp bringing in around 0.4bln. Could be offset by the allowance increasing from current 100mln of profit. Other options include a one-off levy or windfall tax, the implications of which vary significantly. Housing High Your First Home has already been announced. Nothing of note expected to stamp duty or council tax bands, aside from a few loop-hole closures. Mansion-tax threshold cut has been ruled out. Fuel Duty High The September increase was postponed, and may well be pushed further. A one-year freeze costs between 2.5-4.5bln/yr. The Telegraph reports a “green tax” on imported fuel is under consideration; details unknown. HMRC Compliance High Officers have been appointed to high-net-worth individuals, while the tax body is also looking at recovering more of the 60bln uncollected tax gap. A potential significant raiser, but hard to forecast accurately. CGT Medium Income Tax equalisation has been ruled out, with an increase unlikely due to the behavioural impact. Carve outs could be removed, such as the death write-off and an exit levy, raising around 2bln each. Energy Medium Energy Profits Levy currently stands at 38% and is expected until March 2030. Generated 2.6bln in the last period, and is expected at 100mln by 2030. Though, the resumption of North Sea activity could see this forecast revised; Jackdaw could generate 1.4bln of tax by 2029. Gambling Medium Sin tax changes are always possible, and a relatively easy revenue raiser, but no specific measures have been heavily touted. Alcohol Medium Sin tax changes are always possible, though none have been touted heavily. On the flip side, the sector is under significant cost of living and energy pressure, and could see some relief provided as part of any pro-business measure; see Business Rates. Business Rates Medium Small/local business and pubs, entertainment and other such venues could see a cut in local tax rates, at a relatively modest annual cost to the government, but one that would have local financing implications. Weekend reports suggest a 1.5bln local borrowing facility will also be announced. Political implications are mixed. NICs Low-Medium See Income Tax for one suggested approach. Applying the measure to landlords and pensioners could raise around 4bln, BofA suggests. Income Tax Low Ruled out. Raising the personal allowance by 10% would cost an estimated 10bln. One option the Resolution Foundation have suggested would be increasing the basic rate of income tax and cutting employee National Insurance by 2pp; raising 6bln, to the detriment of pensioners. VAT Low Increases ruled out. Currently, the 5% electricity VAT is at 0%, extending to 2027-28 costs c. 1.7bln. Further, a petrol VAT cut is a point of a review, while some reports suggest an online-VAT measure could occur in the future. For reference, cutting all the reduced 5% rates (mainly energy-related) to 0% would cost c. 2.4bln/yr. Pensions Low Would be a surprise, and while a revenue raiser, it is politically very challenging. SPENDING Area Likelihood Outcome (GBP/yr) Cost of Living High Various measures have already been announced, costing over 1bln. The Warm Homes Plan could be expanded, alongside targeted support for low-income households and small businesses; any such measure(s) projected to be temporary, but at a cost of 7bln in the near-term, and then 2bln by 2029-30, BofA projects. The Observer reports that the budget will see the first of a series of “deep reforms” to lower domestic energy costs. Defence High An increase is a near-certain given Healey’s bias and a recent Times article. However, such spending should not weigh on the main current-budget rule if, as expected, it is classed as capital spending, though over 4bln is potentially unfunded for this budget; the credibility of this will be scrutinised significantly. Intended to signal a “downpayment” on getting defence spending to 3% of GDP by 2030. Triple Lock High Announced that the system will be adjusted from 2030 onwards to fund a NCS. Saving 4bln by 2035, according to the IFS and the government believes 15bln by 2040. For reference, in the current FY the difference between the two systems is 9bln under the current lock. Social Care High See Triple Lock, essentially deferred until at least 2030 onwards. Housing High Your First Home has been announced, costs due at the budget, though it does not directly impact the fiscal calculus, but instead will add a currently unclear amount to the GFR/NFR, but is rule-neutral. Welfare Medium Any real change is expected to be deferred, though some small tweaks could occur as a signal that Labour can take action on such issues, until the Milburn and Timms reviews are completed towards the end-2026. Departmental Spending Low Likely to be deferred to the 2027 review. Continuing the Spring Statement’s plan would, adjusted for today, cost around 12bln. Unprotected departments are set to be cut by over 4%/yr in 2029-30, offsetting that would cost 13.5bln. Nationalisation Low Water companies are the main focus given their poor performance, high bills and significant debt. However, nationalisation is very unlikely to be announced at this stage, given the huge costs the OBR associates with it of 78bln, but some new enforcement or similar could occur. Debt Servicing – Unavoidable. ING predicts it could be over 11bln higher by 2029-30. With every 1pp increase in yields (across the entire UK curve) adding 8.4bln by 2029-30, every 100bps of BoE tightening some 5.8bln, and every 1pp increase in RPI c. 7bln.