Government Lifts the ISP Fuel-Tax Discount Again Ahead of Monday's Pump-Price Reset — Diesel Support Climbs to €75.48 per 1,000 Litres and Gasoline to €51.97 as ANAREC Forecasts +10 Cents/L Diesel and +6.5 Cents/L Gasoline

The Ministry of Finance walked the weekly ISP (Imposto sobre os Produtos Petrolíferos) discount up again on Saturday afternoon, raising the per-litre fuel-tax relief one trading session before Monday morning's scheduled pump-price reset and putting the cumulative state subsidy on a litre of diesel into its highest band since the 2022 invasion-of-Ukraine peak. The new schedule lifts the diesel ISP discount by 1.5 cents per litre to €75.48 per 1,000 litres of fuel, and the gasoline 95 ISP discount by 0.6 cents per litre to €51.97 per 1,000 litres, both with effect from Monday 5 May.

The lift is the government's countervailing fiscal lever against an oil-market move pricing this week. The ANAREC distributors' association forecast on Saturday that, absent any Finance Ministry intervention, diesel pump prices would rise about 10 cents per litre on Monday and gasoline 95 about 6.5 cents per litre — figures slightly above the indicative DGEG forecast that Friday's earlier coverage framed at 9.5 cents diesel and 6 cents gasoline. With the Finance Ministry's Saturday adjustment, the net pass-through to Monday's pump board narrows by the corresponding 1.5 cents on diesel and 0.6 cents on gasoline.

What changes on Monday

The cumulative ISP discount applied to a litre of road diesel sold at a Portuguese pump now stands at 7.548 cents per litre under the new schedule, up from 7.398 cents the prior week. The cumulative gasoline 95 discount stands at 5.197 cents per litre, up from 5.137 cents. Both readings are above the threshold the Ministry of Finance held through most of late April and broadly back to the level that prevailed during the late-2024 / early-2025 oil-price softening window.

The mechanism is the same Saturday-afternoon weekly recalibration the Ministry has used since the spring of 2022 under then-Finance Minister João Leão, when the so-called Autovoucher in-pump rebate was retired in favour of a structural reduction in the per-litre ISP rate set out in the OE 2022 fuel-tax tables. The recalibration is applied across all 27,000-odd kilometres of Portuguese road kilometres of fuel-distribution pipeline weekly and shows up at the pump on Monday morning when the major Portuguese chains — Galp, Repsol, BP, Cepsa, Prio and the regional independents — re-tag the per-litre price displays at filling stations from the Algarve up to Bragança.

Cumulative since the March reference week

The Saturday-afternoon adjustment compounds onto a rolling stack of weekly moves that has now been positive for ten of the last fourteen reporting cycles. The cumulative pump-price increase since the 2-6 March reference week — the calibration anchor for the post-Strait-of-Hormuz cycle — runs at roughly 32.8 cents per litre on diesel and 22.4 cents per litre on gasoline 95 before Monday's increment posts. With Monday's increment included, the cumulative diesel rise from the March anchor moves into the 42-cent range and the gasoline rise into the 28-cent range — the largest sustained pump-price climb in any nine-week window since the post-Russia-invasion energy shock.

Inside that nine-week stretch, the weekly moves themselves have not been linear: diesel actually fell 2.2 cents per litre in the most recent week before Monday's posted increase, while gasoline rose 2.8 cents per litre. The compounding pattern reflects the well-documented divergence between the diesel and gasoline crack spreads at European refineries, with the diesel crack tracking heating-oil and trucking demand and the gasoline crack tracking the early summer driving-season build.

The Brent overlay

Brent crude futures rose 2.7% across the week in question — a narrower move than the prior week's 16.54% spike on Strait of Hormuz closure-risk headlines but still firmly inside the elevated post-conflict trading band that has now anchored Brent above $100 per barrel for the better part of a fortnight. The pass-through to Portuguese pump prices runs on a roughly two-week lag through the rotterdam-cargo product channel: this week's posted move at Portuguese stations reflects Brent's mid-April high; next week's posted move will reflect this week's residual climb.

The three-front squeeze on Portuguese household budgets — Brent at $110, Euribor still positive after the 28 April ECB hold, and CPI running at 3.4% — that this site framed earlier this week tightens further with each Saturday-afternoon ISP recalibration that fails to fully neutralise the Brent pass-through. The Ministry's 1.5-cent and 0.6-cent moves softens the Monday pump-board print but does not zero it out.

What Monday's pump board will actually say

Net of Saturday's ISP adjustment, the indicative Monday-morning pump-board increase narrows to roughly 8.5 cents per litre on diesel and 5.9 cents per litre on gasoline 95 — versus the unadjusted 10 cents diesel / 6.5 cents gasoline ANAREC starting forecast. On a 50-litre tank fill, that is roughly €4.25 more for diesel and €2.95 more for gasoline 95 than the previous week's total. On a typical 1,500-kilometre monthly commute pattern in a 6-litres-per-100-km diesel passenger car, the household budget impact lands at roughly €7.65 per month at the new prices, before Monday's correction.

The retail-pump average on Monday morning is expected to land in the €1.95-€2.05/L range for diesel and the €1.92-€1.99/L range for gasoline 95, varying by region and chain — broadly in line with the forecast envelope the DGEG Friday document pegged at €2.05/L diesel and €1.99/L gasoline at the upper end. The Algarve and the Lisboa Metropolitan Area typically print 2-4 cents above the national average; rural Trás-os-Montes and the Beira Interior typically print 1-3 cents below.

Policy framing

The ISP weekly-recalibration mechanism has now run continuously since spring 2022 — through the Costa government, the post-March-2024 transition government and the current Montenegro government — and remains the Finance Ministry's primary pump-price stabilisation tool. The mechanism does not change the OE 2026 statutory ISP rate (which remains the headline tax line); it simply pulls forward a pre-funded discount against that statutory rate. The fiscal cost is absorbed inside the Ministry's energy-tax revenue forecast for 2026 and shows up as a downward revision to the ISP receipts line in the monthly DGO budget execution report rather than as a separate budget line.

The next Saturday-afternoon recalibration window is 9 May, with the corresponding pump-board reset on Monday 11 May. The 5 June ECB Governing Council meeting, the 13 June OPEC+ ministerial and the rolling Iran-negotiations newsflow remain the three exogenous variables that will dictate whether the cumulative ISP-discount stack continues climbing or starts unwinding through June.

Sources: ECO 2 May 2026 (Mónica Silvares, ISP weekly recalibration values + ANAREC forecast); DGEG Friday 1 May 2026 (pump-price forecast). Tier 2 PT primary, Tier 1 substrate via the DGEG forecast.

See also: Pedro Dominguinhos's warning that Iran-war supply-chain disruption is already hitting PRR delivery.