Effets de débordement et coûts d'une sortie monétaire de l'AES sur l'économie ivoirienne : une analyse par modèle spatial de Durbin, projections locales et contrôle synthétique (2006-2024)[Spillover effects and costs of an AES monetary exit on the Ivorian economy: a Spatial Durbin Model, local projections and synthetic control analysis (2006-2024)]

This article extends a previous study on the viability of a monetary exit of the Alliance of Sahel States (AES) — Mali, Burkina Faso, Niger — from the West African Economic and Monetary Union (WAEMU). Whereas the earlier work quantified the cost borne by the exiting countries, the present research shifts the focus to the spillover effects on the remaining members, and particularly on Côte d'Ivoire, the Union's anchor economy (about 38-40 % of regional GDP), the leading intra-community supplier of the Sahel states, and the main logistical hub for the landlocked hinterland through the Port of Abidjan. Using the balanced panel of the eight WAEMU countries (2006-2024), we deploy a triangulation framework: (i) a Spatial Durbin Model (SDM) estimated with a trade-weighted spatial matrix and decomposed into direct, indirect and total effects; (ii) Jordà local projections for the dynamic impulse responses of Ivorian fundamentals to a Sahelian divergence shock; (iii) a synthetic control exploiting the 2022 WAEMU/ECOWAS sanctions on Mali as a quasi-natural experiment of corridor closure; and (iv) a multi-scenario counterfactual simulation through 2026-2032. Findings show that Côte d'Ivoire is the most systemically exposed economy of the Union. The SDM reveals significant spatial dependence and a negative spillover from rising Sahelian structural divergence onto coastal partners' growth and current account. Local projections indicate that a one-standard-deviation corridor-disruption shock lowers Ivorian growth by 0.6 to 0.9 percentage points at a one- to two-year horizon. The synthetic control confirms, for the 2022 episode, a 30-40 % drop in Ivorian exports to Mali during the closure. Simulations suggest an orderly exit would cost Côte d'Ivoire a cumulative 0.8-2.2 % of growth over 2026-2032, against 2.5-4.5 % for a disorderly exit. The article concludes with policy levers to avoid — or at least cushion — such an exit.