What Could Crash the Market? The Risks Nobody Prices In
Every crash needs two things: a market stretched enough to fall, and a trigger that knocks it over. The crash-risk score watches the first. This section watches the second — the missile, the blockade, the tariff, the financing break that arrives from outside the US economy and reprices American stocks before any domestic indicator blinks. Every risk here is tracked with live source data, so you can see the fuse burning before the headline does — never estimates, never predictions.
What external shocks could crash the stock market?
Each risk in this section gets its own page with live data, stated sources and a pre-disruption baseline. If a number cannot be sourced, it is not shown.
Oil Shock
A fifth of the world's oil passes through the Strait of Hormuz and the Bab el-Mandeb. Daily tanker transits from IMF satellite data, against each strait's pre-disruption baseline, alongside the Brent price.
AI Debt
Not all of the AI build-out is paid for in cash. Capex and long-term debt for the biggest builders from their own SEC filings, ranked by debt-to-capex, alongside the CCC-minus-AAA credit spread.
Treasury Dump
Japan is the largest foreign holder of US Treasuries — and those holdings are the ammunition for defending the yen. Monthly TIC holdings against their own peak, alongside the yen and the 10-year yield, with the market-value caveat stated.
Debt Spiral
Interest on the US debt is consuming a rising share of all federal spending, climbing back toward the 1991 record. The quarterly BEA series back to 1947, and the 30-year yield that sets the next decades of interest costs.
What counts as a geopolitical risk to stocks?
The frame for this section: shocks that originate outside the US business cycle and hit US equities through energy prices, supply chains, financing costs, inflation and the rate path. These categories cover nearly every external shock that has ever moved the market.
Energy chokepoints
A fifth of the world's oil squeezes through two straits a few miles wide. There is no pipeline that can replace them — when tanker traffic stops, supply stops, and the price of every barrel on earth resets within days. This is the oil shock scenario, and it is the risk we track live.
Shipping and supply lines
US equities are priced on just-in-time freight. When a canal, a strait or a port closes, diversions add weeks and war-risk premiums reprice overnight — a supply chain risk to equities that lands in the CPI before it lands in any earnings call.
Geopolitical conflict
Wars and blockades do not wait for a Federal Reserve meeting. Geopolitical risk to the stock market hits energy, food and insurance markets first, and US stocks reprice the inflation and rate consequences within months.
Trade policy
Tariffs and export controls are shocks chosen in Washington and Beijing, not in the US business cycle. They rewrite input costs and supply chains faster than any domestic indicator can drift.
Leverage and financing
Manias built on borrowed money end when the lending stops, not when the story does. The AI build-out is the live case: hundreds of billions a year in datacentre construction, financed by debt at the most leveraged builders — and the credit spread is where a financing break would show up first.
Currency and sovereign debt
The Treasury market prices everything else, and its two live stresses run in opposite directions: Japan — the largest foreign holder — may be forced to sell Treasuries to defend the yen, while the US government's own interest bill consumes a rising share of its spending. Either one moves the yield that every stock is valued against.
How does an outside shock reach your portfolio?
The transmission chain is short and it has run the same way for fifty years. By the time it shows up in the domestic indicators, the move in stocks has already happened.
An external shock hits the price of something the US economy cannot substitute — oil, freight, food. That price feeds inflation within weeks. Inflation forces the rate path, and the rate path reprices every stock you own. The 1973 embargo, the 1979 Iranian supply cut and the 2022 invasion of Ukraine all ran down exactly this chain: energy price, inflation, interest rates, equities. You can watch the first link move right now on the live oil shock monitor — tanker transits through Hormuz and Bab el-Mandeb against the Brent price. Everything after that link is arithmetic.
Why watch the risks the crash score can't see?
Internal weakness and external shocks compound each other — an expensive, late-cycle market absorbs a supply shock far worse than a cheap one.
The composite crash-risk score measures how stretched the market is from the inside: six indicators, scored against fixed thresholds, re-read through the day. It tells you how much dry powder a crash has to work with — it does not tell you what lights it. External risks are the other axis: the triggers that turn a stretched market into a falling one. Read the crash score for how vulnerable the market is; read this section for what could light the fuse. You need both, and you need them before the headline, not after.
Frequently asked questions about market risk
What is geopolitical risk to the stock market?
Geopolitical risk is the chance that events outside the US economy — wars, blockades, embargoes, trade fights — reprice US equities. These shocks reach stocks through a predictable chain: energy and freight prices first, then inflation, then the interest-rate path, then earnings and valuations. They matter because no domestic indicator gives you advance warning of them.
Can an oil shock crash the stock market?
It has before. The 1973 embargo sent oil up several-fold and the S&P 500 lost nearly half its value in the bear market that followed; the 1979 Iranian supply cut doubled crude and forced punishing rate hikes; the 2022 invasion of Ukraine spiked Brent and helped drive the fastest tightening cycle in decades. Not every oil spike causes a crash, but every post-war oil shock has shown up in inflation, rates and stock prices within months.
Why does the Strait of Hormuz matter for oil prices and US stocks?
About a fifth of the world's petroleum liquids consumption passes through the Strait of Hormuz, and there is no pipeline network large enough to replace it. If traffic through the strait stops, the oil does not reroute — it stops, and the Strait of Hormuz oil price effect hits Brent within days. That is why this site counts the tankers transiting it daily, from satellite data, against the pre-disruption baseline.
How do supply chain disruptions affect US equities?
US companies run on just-in-time freight, so a closed canal, strait or port raises input costs across entire sectors at once. Diversions add weeks to voyages, war-risk insurance reprices overnight, and the extra cost shows up in consumer prices before it appears in earnings guidance. Equities then reprice both the margin hit and the tighter rate path the inflation forces.
What is the difference between the crash-risk score and these risks?
The composite crash-risk score measures how stretched the market is from the inside — valuation, the yield curve and stress gauges against fixed thresholds. This section watches the other axis: the external triggers that can turn a stretched market into a falling one. An expensive, late-cycle market absorbs a supply shock far worse than a cheap one, which is why the two are read together.
How are these risks tracked on this site?
With live source data, not forecasts. The oil shock page counts daily tanker transits through the Strait of Hormuz and the Bab el-Mandeb from IMF PortWatch satellite data and pairs them with the Brent price from FRED, each against a stated baseline. If a number cannot be sourced, it is not shown — nothing on these pages is an estimate.
Get told when a risk starts moving
One email a week when the composite score moved — with the chokepoint readings alongside the six internal indicators, so you see both axes of risk at once. The shock shows up in this data before it shows up at the pump.
One email a week, and only in weeks the composite score actually moved. No account, one click to unsubscribe, and the address is never shared.
Explore the Data
Tanker transits through Hormuz and Bab el-Mandeb, against Brent
Who is financing the AI build-out with debt — SEC-filed capex and leverage
Japan's trillion-dollar Treasury holdings, the yen and the 10-year yield
The interest bill on the US debt, against the post-war record share of spending
The internal axis — valuation and stress gauges behind the crash-risk score
The live combined risk assessment
When did the market last look like this — and what followed
Every formula, data source and threshold, stated openly