AIM market winners and losers since Iran war broke out

Except for Brazil, where there is a gain of less than 1%, all the world’s major stock markets have fallen since the US and Israel started to bomb Iran at the end of February. AIM is the worst performing of them all, although the Main Market measures have also done badly.

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European markets, along with Japan, have been hardest hit. The DAX in Germany is nearly 10% lower and the CAC 40 in Paris has declined by 9%. The FTSE 100 index is down 7.6%. The US is lower, but it has held up better - the Dow Jones index is 6% weaker and the Nasdaq tech index is 2.4% lower.  

The FTSE AIM All Share index has fallen by 11.2% between 27 February 2026 and 19 March 2026. Initial reaction to the outbreak of war was modest before a sharp downturn began on 3 March.

Performance of major stock markets

Source: ShareScope.Past performance is not a guide to future performance.

Drone and missile strikes on refineries in Iran and other countries in the Middle East, plus difficulties in transporting oil through the Strait of Hormuz, have led to soaring oil prices. Brent crude was around $70/barrel at the end of February compared with around $105/barrel currently, although it is volatile and moving towards the peak in 2022.

The conflict in the Middle East has made further interest rate reductions appear less likely, and the Bank of England is maintaining borrowing costs. There are concerns that there could be upward movements in rates, with rising oil prices likely to push up inflation – possibly to 3.5%. This is a negative for the stock market, which had been hoping for interest rate cuts.

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It is not just the cost of shipping oil that is rising. Freight rates and related insurance costs are also increasing, which will put further pressure on prices. One week ago, spot global container shipping prices had risen by 12% since the end of February. Supply chains could be disrupted and hinder the ability of some companies to get their products to market.

Fuel cost rises will also make it dearer to transport goods around the country. This will put even more pressure on inflation.

AIM had already underperformed in 2025, particularly the junior market’s UK-focused companies. The current underperformance is partly due to sectors that did well last year. The mining sector has been much weaker in the past three months.

AIM 100 index

The FTSE AIM 100 index, which has significant representation from mining companies, is the worst performer of all so far with a 12.6% decline since 27 February.

There are 13 of the 100 companies that have a higher share price over the past three weeks, with one unchanged.

Four of the top six performers are oil and gas companies, the only ones in this index - two are producers and two are explorers with no production.

PetroTal Corp (LSE:PTAL) has the highest rise of 34.9%. The South America-focused company is targeting average 2026 production of 11,750-12,250 barrels of oil per day. Annual adjusted EBITDA (profit) was expected to be $30 million at $60/barrel after erosion control expenses. Based on the current oil price, the outcome could be much better.

UK North Sea oil and gas producer Serica Energy (LSE:SQZ) is currently 10.8% higher since war broke out and has risen 125% over the past year. Early in March, Chancellor Rachel Reeves confirmed that she will replace the current windfall tax for North Sea producers with a more predictable tax regime. That has also helped the share price.  

Serica Energy averaged 27,600 barrels of oil equivalent per day in 2025. This year average production is expected to be 43,000 barrels of oil equivalent per day.

Alaska-focused Pantheon Resources (LSE:PANR) shares have been volatile, and the price declined 86% last year, but it has rebounded 23% to 9.17p/share in the past three weeks. At the beginning of the year, $10 million was raised at 7p/share, which will finance the flow testing of the Dubhe-1 appraisal well and seismic for the Kodiak prospect. So far, there have been mixed results from exploration.

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Rockhopper Exploration (LSE:RKH) has not published any news in the past couple of months, but the share price is 7.1% ahead during the conflict period. At the end of 2025, financial close was achieved on the Sea Lion project in the North Falkland Basin. The total cost of phase one of this project is $2.1 billion, and the first production is still some way away. The first well will not be drilled until the end of the year at the earliest. Phase one production could reach 50,000 barrels per day.

The other companies in the top six performers are renewable energy generator Greencoat Renewables (LSE:GRP) and software solutions firm AdvancedAdvT Ltd Ordinary Shares (LSE:ADVT).

One of the other gainers is MS International (LSE:MSI), which supplies petrol station superstructures and forgings, but the relevant business is the defence sector. The company supplies naval weapons to the US and German navy, as well as manufacturing land weapons.

Cohort (LSE:CHRT) is another defence business and, although the share price has fallen, it has still outperformed AIM.

10 best-performing AIM 100 stocks

Source: ShareScope. Past performance is not a guide to future performance.

Precious metals

The silver price has slumped by 22.6% over the past three weeks and gold is 11.9% lower. Even so, they are up 114% and 52.5% over the past year, respectively. The fall in the silver price provides some good news for electrical products suppliers that use the metal.

Rising oil prices and a strengthening US dollar, due to strong oil production in the US, have hit the gold price. To be fair, there had already been a correction in the gold price following a sharp increase. There was even an initial rise in gold at the start of the conflict before it began trending downwards. Higher inflation could revive interest in gold.

Five of the 10 worst performers in the AIM 100 are mining companies, with the bottom three falling by around one-third. Many of these are gold producers, but not all of them. Greatland Resources Ltd (LSE:GGP), which was one of the best performers last year, is one of the worst.

Central Asia Metals (LSE:CAML) is 34.4% lower, but that is partly because the estimated life of its Sasa zinc and lead mine in North Macedonia has been cut by five years. That will lead to a non-cash impairment charge of up to $120 million.

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Platinum is 17% lower and Sylvania Platinum Ltd (LSE:SLP) is the second-worst performer. The gold miners all declined by one-fifth or more.

The only mining company with a gain is potash project developer Kore Potash (LSE:KP2). There is a potential bidder in the wings and potash is an alternative to fertiliser made with gas.

The flip side of the rising oil price is potential large cost increases for companies that use significant amounts of energy. However, many companies have a policy of buying a proportion of their requirements ahead of time, so short-term movements will not have a large effect. For example, Johnson Service Group (LSE:JSG), which moved to the Main Market last year, has fixed more than 90% of electricity and gas prices for the first half and more than three-quarters for the second half of 2026. More than 70% of gas prices are fixed for next year.

10 worst-performing AIM 100 stocks

Source: ShareScope. Past performance is not a guide to future performance.

There are AIM companies, such as Michelmersh Brick Holdings (LSE:MBH) and Churchill China (LSE:CHH), that are major energy users. It is difficult to assess how much they have bought forward and whether they will be severely hampered by higher energy prices. Both these companies are due to report their 2025 results soon, and there should be greater clarity then.  

For some companies there is a mixed outlook. Airlines will be hit hard by fuel price rises and flights being disrupted to Middle East destinations. However, people are switching their trips to places such as Spain, which will offset some of the negative outlook. However, the negative will take precedence.

Airline and tour operator Jet2 Ordinary Shares (LSE:JET2) shares have fallen 14.3%. This came just after a positive trading statement a couple of days earlier. Jet2 was pleased with summer bookings and it was focusing on growing market share with attractive pricing. That will be difficult if plane fuel rises and stays at high levels. On 9 March, Barclays cut its share price target from £19 to £17.

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The potential for higher interest rates will hit companies with high borrowings, many of whose share prices are already held back by a debt burden.

It will also hamper the housing market and could hurt consumer confidence in general, which is already weak. Housebuilder Springfield Properties Ordinary Shares (LSE:SPR), in the AIM All-Share index, is 15% lower, yet it could be a beneficiary because it is focused on the north of Scotland where there is planned infrastructure spending. A rising oil price could also boost the oil sector in the region thereby having a knock-on effect on demand for housing.

Given the uncertainty caused by conflict in the Middle East, expect it to continue to hamper progress among AIM companies in general until there’s some kind of resolution.  

Andrew Hore is a freelance contributor and not a direct employee of interactive investor.