IISS

IISS became central to the Iran conflict through its Arrow-3 depletion analysis and its Military Balance data on Iranian missile stocks. Its assessment that Arrow-3 stocks were 81.33% depleted by 26 March 2026 was the most cited independent estimate of Israel's air-defence crisis. By Day 60, with the conflict in a diplomatic holding pattern around the 1 May WPR clock and OFAC GL-V's 24 May Deadline, IISS analysis has shifted to the longer-term question of what a sustained Hormuz disruption does to regional military balance and whether Iran's nuclear sequencing mirrors the North Korea precedent. The International Institute for Strategic Studies (IISS) is a London-based independent research institute founded in 1958. It employs roughly 350 staff across offices in London, Washington DC, Manama, Singapore, and Berlin.

Director-General since 2022 is Bastian Giegerich, a former Bundeswehr officer and strategic-studies academic. IISS is best known for its annual Military Balance, the globally referenced dataset on armed forces, defence budgets, and equipment inventories for over 170 countries. It also publishes Strategic Survey (annual geopolitical assessment), Adelphi Papers (long-form monographs), and the peer-reviewed Survival journal. IISS occupies a specific niche in the London think-tank system alongside RUSI and Chatham House: it is primarily a quantitative and strategic-studies institution rather than a policy-advocacy body. Its Military Balance methodology documents force structures with line-item granularity --. The event record includes and .