Approximately 20 million barrels of oil and petroleum products transit the Strait of Hormuz on an average day. The figure is so large and repeated so frequently in energy commentary that it has become almost abstract. Decomposing it into its constituent flows reveals a more specific picture of what is actually at stake — which countries, which companies, which commodity streams, and which supply chains run through twenty-one miles of contested water.

Before a single missile is fired, before a mine is laid, before a naval vessel changes course, the insurance market registers the threat. War risk premiums on tankers transiting the Persian Gulf are among the most sensitive geopolitical indicators available. They move faster than official statements, faster than military repositioning, and faster than most news coverage. The underwriters at Lloyd’s of London are not strategists, but their pricing reflects a continuous aggregation of threat intelligence that rivals most government assessments.