Mount Etna’s current summit activity, including ongoing Strombolian explosions at Voragine crater and ash plumes reaching 4,000–4,300 m as reported by Toulouse VAAC on September 10–11, forms the main driver behind the near-even 52.5% market-implied odds for a VEI 2+ event in 2026. Multiple short effusive and explosive episodes earlier in the year, documented by INGV bulletins through August, produced lava flows and mild ash emissions whose precise explosivity indices remain under review, creating genuine uncertainty about whether they meet the VEI 2 threshold of 1–5 km plumes and associated ejecta volume. Traders weigh Etna’s historically high frequency of moderate summit events against the possibility of rapid decline into lower-level degassing, with resolution hinging on forthcoming INGV seismic, infrasound, and satellite thermal data plus any escalation in tremor amplitude or new fissure opening.