International Trade and Investment Program Meeting, Spring 2026

Why It Matters

The analysis shows that trade liberalization can cut national welfare when a few firms dominate, urging policymakers to account for profit losses and sectoral disparities when designing trade agreements.

Key Takeaways

• Rising market concentration reduces competition, affecting trade welfare.
• Trade opening can lower prices but cut firm profits under oligopoly.
• Welfare formula separates price effects from profit effects for policymakers.
• Chile case shows welfare under Cournot is 55% of monopoly.
• Sectoral heterogeneity determines which industries lose from trade liberalization.

Summary

The presentation introduced a new welfare framework for analyzing trade under oligopolistic competition, focusing on how a small, fixed number of firms in each market shape welfare outcomes. Building on the nested CES model of Armington and the classic Brander‑Krugman literature, the authors derived a decomposition that isolates price effects from profit effects, allowing policymakers to evaluate iceberg‑type trade shocks without invoking tariffs. Key findings emerge from an empirical application to Chile. Using firm‑level customs data on domestic and export shares, the authors compare welfare under Cournot‑style competition with that under monopolistic competition. Prices fall more under Cournot, reflecting strategic price competition, but the reallocation of market shares depresses Chilean firms’ profits, yielding a net welfare that is only 55 % of the monopolistic‑competition benchmark. The framework also identifies sector‑specific heterogeneity, showing that some industries would experience net losses while others could gain. The authors highlighted that the welfare formula is fully implementable from observable revenue shares and conduct assumptions, a point underscored by the quote, “From observed firm shares we can tell which sectors are more likely to be negatively impacted through trade.” This bridges a gap between theoretical models and real‑world data, offering a practical tool for trade policy analysis. Implications are clear: trade liberalization can be welfare‑reducing in markets dominated by a few powerful firms, and policymakers must consider both price reductions and profit redistributions. The heterogeneity across sectors suggests that blanket trade agreements may mask significant distributional effects, prompting a need for targeted adjustment measures.