The plastics bill for Hormuz is still being written

Oil traders have largely sold the war. The plastics market cannot, because the molecules are still missing. Since Iranian forces declared the Strait of Hormuz closed on 4 March, the polymer chain has absorbed the largest supply shock in its modern history, and prices across polyethylene, polypropylene and their feedstocks remain far above their February levels even as crude drifts back towards its pre-war range.

What happened

The feedstock repriced first. Spot naphtha in Europe rose from USD 585 to 590 a tonne on 27 February to USD 695 to 700 a tonne by 5 March, according to Polymerupdate. By 25 March, Singapore spot naphtha had reached USD 1,000 a tonne, a rise of roughly 60 per cent in a month, in a market that had been in structural oversupply weeks earlier.

The derivatives followed. The ICIS global petrochemical index rose 32.7 per cent month on month in March, the steepest move since the index began in 2000, with Northeast Asia up 42.6 per cent on an 88.6 per cent jump in ethylene. European ethylene contracts for April settled at EUR 1,595 a tonne, an increase of EUR 450 a tonne on March and the largest monthly rise on record. By mid-March, ICIS counted 31 force majeure or sales allocation notices across Asia and the Middle East, and Dow's chief executive estimated that up to half of global polyethylene supply was affected, delayed or obstructed.

Why the plastics chain is so exposed

Crude has partial workarounds: Gulf pipelines carry 3.5 to 5.5 million barrels a day around the strait. The plastics chain has almost nothing comparable. ICIS data show around 84 per cent of Middle East polyethylene capacity depends on the strait for waterborne exports, and Middle East cargoes covered roughly 80 per cent of Asia's seaborne naphtha imports in 2025. Drewry estimated a prolonged closure removes about 24 per cent of global seaborne naphtha. Around a third of seaborne methanol and nearly half of seaborne sulphur trade move through the same water. When the strait shut, the loss was physical capacity, not a risk premium, and physical capacity does not reopen on a headline.

The case for lower resin prices

The industry entered this crisis in the fourth year of a downturn. Moody's had spent 2025 downgrading producers on the grounds that global capacity, led by Chinese expansion, had outrun demand, and Braskem's polyethylene spreads over naphtha stood near USD 339 a tonne in the first quarter. If transits normalise, Middle East exports return, Asian crackers restore run rates, and the market can tip back into the surplus that defined 2022 to 2025. US ethane-based producers, insulated from naphtha economics, are already running above 90 per cent utilisation and exporting at record volumes. Demand is the other brake: sustained high resin prices feed through to packaging, autos and construction, and buyers respond by using less.

The case for higher

Reopening is not recovery. ICIS estimated in April that Middle East petrochemical exports need 12 to 18 months to normalise even after the strait reopens, through insurance repricing, carrier service resumption, force majeure unwinding and inventory rebuilding. That clock has barely started: after renewed fighting last week, Windward tracked just six vessels crossing the strait in twelve hours, against 18 to 22 daily crossings earlier in July. Iran's Persian Gulf Strait Authority still tells shipowners that vessels outside its approved route carry no safe passage guarantee. And every converter that ran down stocks between March and June now wants to rebuild them, which supports cargo demand well past any political settlement.

What it means for buyers

Crude is no longer a usable proxy for polymer cost. A procurement desk that priced its 2026 resin contracts off the oil screen has been wrong twice this year, once on the way up and once by expecting relief that never reached the resin market. The number that matters is the one for your specific commodity, with its own supply map, its own force majeure list and its own recovery clock.

If your supply line is down

Global Economic Bridge works with leading petrochemical suppliers around the world, and finding replacement supply under pressure is a service we run, not a favour we improvise. If the disruption has reached your industry, the Emergency Supplier Replacement Pack from GEB Materials identifies alternative suppliers or routes for a failed supply line, runs a fast credibility check on each, and hands you a ranked set of options with a recommended immediate action, within 48 hours of the green light.

Track the commodity, not the headline

For the months either side of a crisis, Global Economic Bridge follows this market commodity by commodity. The Commodity Intelligence Monitor from GEB Intelligence is a monthly briefing on a single commodity of your choice: price action with sources, dates and units, changes in trade flows and logistics, and the decisions the month's data forces. It costs USD 149 a month and you select the commodity at purchase.

Sources: Polymerupdate Research, 7 March 2026. ICIS IPEX March 2026 release via market reports, April 2026. Financial Content market note, 30 March 2026. ICIS via IOM3, 4 March 2026, and ICIS naphtha coverage, May 2026. Congressional Research Service, R45281, updated 2026. IDNFinancials citing Reuters and LSEG, 27 March 2026. World Economic Forum, April 2026. Atlantic Council EnergySource citing Drewry, 23 March 2026. Al Jazeera, 10 and 13 July 2026. C&EN, 5 March 2026.