US Futures Fall as Navy Seizes Iranian Vessel, Brent Jumps 8%

US equity futures slid 0.4% to 0.5% Monday as a US Navy seizure of an Iranian vessel stoked fresh fears over Middle East stability and oil supply security. The move came as a ceasefire deadline loomed, injecting uncertainty into ongoing peace talks and triggering a broad risk-off shift across markets. Brent crude surged 8%, the sharpest near-term signal of how traders are pricing renewed disruption risk to Gulf shipping lanes. The Iranian vessel seizure is the operative catalyst: any escalation that threatens Strait of Hormuz transit directly pressures global crude supply, with Brent's reaction suggesting markets are not treating this as a contained incident. Equity investors are repricing geopolitical risk premium simultaneously. Watch whether diplomatic channels stabilize before the ceasefire deadline expires, that outcome will determine whether the oil spike and futures weakness extend or reverse into the week.