Houthi forces' rapid September 2026 advances along Yemen's Red Sea coast, including captures of Mokha port, Perim (Mayyun) Island, and the Hanish Islands, have placed the group in control of both shores and key islands flanking the Bab el-Mandeb Strait. These gains enabled enforcement of a Saudi-linked shipping embargo and triggered sharp drops in transits—daily crossings fell to around 15–24 vessels from prior norms near 30–33, with tanker and container traffic notably reduced—while oil prices rose amid rerouting around the Cape of Good Hope. No maritime authority has declared formal closure, and IMF PortWatch data show volumes above the Polymarket threshold of a 7-day moving average of 10 or fewer arrivals, though the UN has flagged heightened volatility. Trader consensus reflects these territorial shifts and sustained threats elevating effective closure risk through year-end, tempered by continued limited transits and Houthi statements asserting orderly navigation for non-targeted vessels.