Ampol (ASX: ALD) has delivered a huge jump in first-half earnings, after the war in the Middle East disrupted global fuel markets and sent refining and trading returns sharply higher.

The fuel giant, which returned to the Ampol name in 2020 after decades operating as Caltex Australia, reported replacement cost operating profit after tax of $857.2 million for the six months to June 30, compared with $180.2 million in the same period last year. Replacement cost operating profit is Ampol's preferred measure of underlying performance because it strips out the inventory valuation swings that flow through statutory accounts.

Statutory net profit also swung dramatically, reaching $1.36 billion compared with a $25.3 million loss in the first half of FY25.

The strength of the result allowed Ampol to more than quadruple its interim dividend to 185 cents per share, up from 40 cents previously.

The Middle East conflict was a major factor behind the earnings surge, with disruption across global oil and refined fuel markets creating unusually strong conditions for refiners and traders. The 12-day war between Israel and Iran in June heightened fears of disruption to shipping through the Strait of Hormuz, the chokepoint that carries roughly a fifth of the world's oil trade, lifting both crude prices and regional refining margins during the period.

Ampol's Lytton refinery was a major beneficiary of those conditions. Gross profit from the Brisbane facility rose to $533.4 million from just $1.1 million a year earlier, highlighting the extraordinary change in refining economics over the period. Lytton is one of only two oil refineries still operating in Australia, alongside Viva Energy's Geelong plant, after BP closed its Kwinana refinery in Western Australia and ExxonMobil shut its Altona facility in Melbourne in 2021.

The company's international business also benefited from the market dislocation, with earnings before interest and tax increasing to $307.5 million from $2.8 million.

Across fuels and infrastructure, EBIT climbed to $1.13 billion from $118.3 million, while convenience retail EBIT increased 12 per cent to $204.5 million.

Ampol also completed its acquisition of EG Australia, the local fuel and convenience network formerly owned by Britain's EG Group, during the period, giving its retail network another avenue for growth. Management expects the acquisition to contribute to earnings during the second half and remains confident of generating between $65 million and $80 million in annual cost synergies within two years.

The near-term outlook remains closely tied to energy markets. July earnings were ahead of the same month last year, with the Lytton refinery continuing to support performance.

However, refinery production is currently being constrained by a 70-day maintenance shutdown that began on July 30. Ampol expects output from Lytton to run at about 70 per cent of normal during the shutdown.

The maintenance had been delayed earlier in the year as Ampol sought to protect domestic fuel availability amid heightened concerns around potential supply disruptions linked to the Strait of Hormuz.

Ampol enters the second half with several structural positives. The EG Australia acquisition expands its retail footprint, the company continues to benefit from its trading capabilities, and the Lytton refinery remains strategically important to Australia's domestic fuel supply.

Ampol is also in discussions with the federal government over longer-term support for Australia's remaining oil refineries. The company and Viva Energy are seeking support for the investment required to keep their facilities operating beyond the coming years, building on the Fuel Security Services Payment introduced in 2021 to keep the last two refineries open after the 2021 closures.