Strait of Hormuz tensions deepen as Iran attacks commercial shipping; supply crunch emerges with Brent at $90
Measured from 20 Jul 2026 (event start), not the 20 Jul 2026 announcement
Defense contractors moved +11.4%, the largest reaction measured, though not statistically significant, meaning it may reflect normal market noise rather than the event itself. This is a provisional result; the full measurement window is not yet complete.
LMT, RTX, NOC · up
What Happened
Iranian military assets, explicitly targeted by US airstrikes, have conducted coordinated attacks on commercial shipping infrastructure and vessels in the Strait of Hormuz, with the US military stating its campaign aims to degrade Iranian capabilities for such attacks. Kuwait Petroleum Corporation reported Iranian strikes on key Kuwaiti oil facilities on July 19-20. The Strait carries approximately 20 to 30 percent of global crude oil exports, making it the world's most critical energy chokepoint. Shipping insurance premiums have spiked, and multiple vessels have been diverted around the Cape of Good Hope at significant time and fuel cost penalties. The conflict has created a supply crunch that has not yet fully manifested in crude prices, suggesting asymmetric upside risk for oil.
Strait of Hormuz is the ultimate energy supply constraint; maritime attack signals Iranian willingness to extend conflict beyond military targets into economic strangling; market mispricing supply crunch risk
Maritime attacks ongoing as of July 20, 2026; Strait remains nominally open but operationally disrupted with elevated insurance and rerouting costs; no indication of imminent return to normal shipping patterns
Reporting on July 20 confirms Iranian targeting of commercial vessels and shipping infrastructure in the Strait of Hormuz during the ninth consecutive night of US strikes; no date given for ceasefire of maritime attacks.
Read how dates work →Partial reaction shown. Significance flags are marked provisional and may change as more price data accumulates.
How To Read This
Each sector below is a basket of named stocks. The percentage shown is the move beyond the overall market (S&P 500) , what event studies call the . A move only counts as when it sits clearly outside that basket's normal weekly swings.
How Much Sectors Moved
Path over time. Click a sector in the legend to toggle it. Dashed lines mark key moments.
Defense contractors moved most at +11.4% against the market, the direction you would expect from a waterway block. None of the moves cleared the significance threshold. Read the direction as flavour, not signal.
Volatility
Volatility measures how erratic prices became, a separate signal from the direction of the move.
Market fear rose modestly
- Oil tanker operators52% → 26%2.0x calmer after
- Oil & gas producers27% → 27%volatility roughly unchanged
- Defense contractors31% → 41%1.3x more volatile after
- Gold23% → 21%1.1x calmer after
- Airline stocks38% → 48%1.3x more volatile after
The VIX rose 8.0 percent across the window, a mild move. Read this as the market's demand for protection, not the direction of any single sector.
A ratio above 1.00 means the sector's daily-price swings widened after the event. Defense contractors became the most erratic at 1.32×, and 2 of 5 sectors traded meaningfully wider than they did before. Volatility is a separate signal from direction: a sector can end flat and still have traded wildly along the way.
Phases
| Sector | Peak Move | Peak Day | Reverted By |
|---|---|---|---|
| Oil tanker operators | +6.4% | Day 7 | Still elevated |
| Oil & gas producers | +13.1% | Day 7 | Still elevated |
| Defense contractors | +10.0% | Day 5 | Still elevated |
| Gold | -2.6% | Day -2 | Day -1 |
| Airline stocks | -10.0% | Day 3 | Day 5 |
The reaction peaked around day 4 on average. 2 of 5 sectors reverted inside the window, 3 were still elevated at the close. A reaction that reverts is a shock priced in; one that stays is a re-rating.
Historical Precedents
Companies Most Affected
Measured 10 days after the event. Reaction still developing; the full window is not yet complete.
This tool informs your decision. It does not give investment advice.