How the Hormuz Closure Is Hitting ASEAN Differently

When the IRGC declared complete control of the Strait of Hormuz on 4 March 2026, it triggered the largest disruption to global oil supply in recorded history. By 12 March, Brent crude had closed above USD100 per barrel for the first time since August 2022, intraday prices briefly hitting USD119.50. The IEA responded with its largest-ever emergency reserve release: 400 million barrels. The market shrugged it off.

The instinct is to reduce this to a single macro thesis: oil up, emerging markets down. That framing is analytically insufficient. The Philippines, Malaysia, Indonesia, Thailand and Singapore face structurally different transmission channels, fiscal buffers and policy constraints. A portfolio manager running a single ASEAN allocation is not managing one oil shock. They are managing five simultaneously.

The Philippines: Maximum Exposure, Minimum Buffer

No ASEAN economy is as exposed as the Philippines. MUFG Bank research confirmed that 95% of the country’s crude oil imports pass through the Strait of Hormuz. The Manila Bulletin reported that every USD10 per barrel increase in oil prices widens the Philippines’ current account deficit by approximately 0.5% of GDP – placing the deficit near 3% of GDP at sustained current prices.

The currency channel has already activated. The peso closed at PHP 59.735 on 14 March 2026, a fresh record low, according to the Philippine Daily Inquirer. MUFG’s model-based estimates project USD/PHP at PHP 60.00–61.00 under sustained USD100 oil, with the BSP’s interest rate differential with the US already compressed to a historic low of 50 basis points following the February rate cut. BSP Governor Eli Remolona stated publicly that the central bank may be forced to end its easing cycle if oil holds at USD100, a threshold now exceeded and sustained. For fund managers with Philippine equity exposure, the dual pressure of peso depreciation and a potential BSP rate reversal creates a scenario 2025 models did not price.

Malaysia: The Net Exporter Paradox

Malaysia is ASEAN’s only net oil exporter among the five markets, and the structural reality is more complicated than the headline implies. Malaysia’s 2026 budget was constructed on a Brent assumption of USD60-65 per barrel, confirmed by Finance Minister II Datuk Seri Amir Hamzah Azizan in October 2025. At that price, Petronas was projected to pay MYR 20 billion in dividends, its lowest since 2017 and 38% below the RM 32 billion committed for 2025.

Higher oil prices improve Petronas’s upstream earnings and could increase dividend capacity – Moody’s noted this partial offset in March 2026. However, that uplift is partially absorbed before it reaches the government. Economy Minister Akmal Nasrullah Mohd Nasir observed publicly that higher LNG import costs and rising downstream subsidy obligations may offset much of the upstream gain.

Malaysia’s RON95 retail price of RM 1.99 per litre is politically fixed regardless of market prices – a commitment that cost the government MYR 20 billion annually as recently as 2023, according to Prime Minister Anwar Ibrahim’s Budget 2025 speech. A couple of days ago, he projected it could reach MYR 24 billion by year-end 2026 at MYR 2 billion per month if the conflict persists.

CGS International Securities Malaysia chief economist Nazmi Idrus warned that a sustained spike in fuel subsidy costs “could potentially overturn the fiscal consolidation trajectory that the government has planned.” At USD100 oil, Malaysia is a net beneficiary in theory.

At the point where subsidy costs erase the upstream dividend uplift, the fiscal arithmetic narrows sharply. The ringgit, meanwhile, does not trade on upstream revenues alone; it trades on global risk sentiment and risk-off flows have historically punished MYR regardless of Malaysia’s oil producer status.

By 12 March, Brent crude had closed above USD100 per barrel for the first time since August 2022, intraday prices briefly hitting USD119.50.

Indonesia: The Subsidy Equation Under Pressure

Indonesia’s fiscal exposure is direct and quantifiable. The Jakarta Post reported that the 2026 budget assumed an Indonesian Crude Price of USD70 per barrel. Every USD1 increase above that adds Rp 10.3 trillion in subsidy costs while returning only Rp 3.6 trillion in revenue. With Brent trading above USD100 through mid-March, the budget is structurally underwater.

Indonesia’s position is partially buffered by import diversification: only approximately 19% of its oil imports transit Hormuz, with the balance sourced from Nigeria, Angola, Brazil and Australia, according to the Jakarta Globe. But Bank Permata chief economist Josua Pardede estimated that every 10% increase in global crude prices widens Indonesia’s fiscal deficit by approximately Rp 77 trillion (USD4.8 billion).

The rupiah hit a record low of Rp 16,990 on 9 March. Coordinating Minister Airlangga Hartarto confirmed the government will not raise subsidised fuel prices in the near term – absorbing the shock through the state budget until the arithmetic forces a recalibration.

Thailand: The Dual Shock of Oil and LNG

Where Indonesia’s exposure is primarily fiscal, Thailand’s operates through two simultaneous channels. The country generated 68.4% of its electricity from gas in 2024, according to Foreign Policy, with domestic production covering approximately 55% of needs.

The balance –⁠ including LNG sourced from Qatar –⁠ transits Hormuz. Nomura analysis, cited by CNBC, identified Thailand’s net oil imports at 4.7% of GDP, the highest share in ASEAN: every 10% rise in oil prices worsens the current account balance by approximately 0.5% of GDP.

Thailand’s National Economic and Social Development Council modelled the outcome: a prolonged closure pushes GDP growth from 2% to 1.3%. Thai petrochemical firm Rayong Olefins, a unit of Siam Cement Group, suspended plant operations in March after losing access to naphtha and propane.

For investors in Thai industrial equities, the supply chain disruption is not a downstream risk. It is already in the income statement.

Singapore: The Trade Transmission Risk

Singapore produces no oil and carries a trade-to-GDP ratio above 300%, meaning the shock enters not through one channel but through every price in the economy simultaneously. Fortune confirmed that Qatar supplied 45% of Singapore’s LNG in 2025.

With Asian LNG spot prices more than doubling within a week to USD25.40 per million British thermal units –⁠ the highest since 2023, according to Bloomberg –⁠ gas-fired power stations, which supply the majority of Singapore’s electricity, are absorbing input cost increases that cannot be immediately passed through to regulated tariff structures.

BMI, a unit of Fitch Solutions, estimated the conflict adds 7 to 27 basis points to headline CPI across Asia, with Singapore in the upper range given its LNG dependency and complete absence of domestic energy production. For Singapore-listed REITs and industrials with fixed utility cost structures, the margin pressure is already present in the current quarter’s operating cost line.

The Monetary Authority of Singapore (MAS) manages inflation through the slope, width and centre of the Singapore dollar nominal effective exchange rate band rather than interest rates – a mechanism that gives it precision other central banks lack but also creates a specific signalling dynamic that fixed income and FX traders need to monitor.

In October 2022, facing a comparable imported inflation spike, the MAS delivered an off-cycle tightening by re-centring the S$NEER band at a higher level, strengthening the SGD against its trading basket and directly reducing the SGD cost of imported goods.

If March-April 2026 CPI data confirm sustained pass-through from the LNG and freight shock, the same mechanism is available and the precedent for using it outside the scheduled April review window is already established.

ING’s research note of 12 March was direct: “The only way to see oil prices trade lower on a sustained basis is by getting oil flowing through the Strait of Hormuz. Failing to do so means that the market highs are still ahead of us.”

The Forward View

ING’s research note of 12 March was direct: “The only way to see oil prices trade lower on a sustained basis is by getting oil flowing through the Strait of Hormuz. Failing to do so means that the market highs are still ahead of us.” Iran’s new Supreme Leader Mojtaba Khamenei has publicly committed to keeping the Strait closed as a tool of pressure.

The five frameworks above are not interchangeable. Philippine positions require immediate currency hedge review and a BSP rate reversal scenario built into equity models. Malaysian exposure demands a net fiscal analysis that runs both the upstream revenue uplift, and the downstream subsidy drag simultaneously.

Indonesian portfolios need a deficit stress-test at USD90, USD100 and USD120 Brent. Thai industrial holdings require supply chain reviews at company level now, not at quarter-end. Singapore positions require monitoring the MAS policy response window before inflation pass-through entrenches.

The managers who navigate this well will be those who had already stress-tested each market independently –⁠ currency hedge reviewed in Manila, fiscal scenario modelled in Kuala Lumpur, deficit trajectory mapped in Jakarta, supply chain audited in Bangkok, MAS policy window monitored in Singapore –⁠ before the next price move forces the analysis under pressure.