آثار عضویت ایران در گروه بریکس پلاس بر شاخص‌های کلان اقتصادی با استفاده از مدل تعادل عمومی محاسبه‌پذیر

Purpose

The expansion of economic cooperation among emerging economies and the formation of the BRICS+ framework represent a significant shift in the global economic order, reshaping trade flows, investment patterns, and strategic alliances. As Iran has officially joined BRICS+, the question of how integration within this economic bloc affects the country’s macroeconomic performance becomes particularly relevant. This study aims to analyze the macroeconomic effects of Iran’s accession to the BRICS+ group through the lens of trade liberalization and tariff reduction. Specifically, the research seeks to evaluate how reciprocal tariff reduction between Iran and BRICS+ member countries influences key macroeconomic variables, including real gross domestic product (GDP), sectoral domestic production, import and export volumes, trade balance, terms of trade, equivalent variation (as a welfare indicator), and sectoral value added. By focusing on interaction effects between domestic production structures and international trade linkages, the study seeks to provide a comprehensive and empirically grounded assessment of the economic implications of Iran’s participation in a major emerging multilateral economic alliance. The analysis contributes to the existing literature by adopting a global multi-regional equilibrium framework capable of capturing simultaneous adjustments across markets, sectors, and regions—an approach that has been largely underutilized in prior studies concerning Iran’s international trade agreements.



Methodology

The research employs a multi-regional Computable General Equilibrium (CGE) model based on the standard Global Trade Analysis Project (GTAP) framework, using data from the GTAP Version 10 database with 2014 as the base year. The global economy is aggregated into three regions: (1) Iran, (2) BRICS+ member countries, and (3) the rest of the world. Economic activities are classified into three major sectors: agriculture, industry, and services. The model incorporates nested constant elasticity of substitution (CES) production functions for firms, Constant Difference of Elasticities (CDE) functions for household consumption, and the Armington assumption to differentiate between domestically produced and imported goods. A Constant Elasticity of Transformation (CET) function guides producers' allocation of supply between domestic and export markets.

The model is solved in a comparative static setting using the RunGTAP interface. Ten policy scenarios are simulated, representing reciprocal tariff reductions between Iran and BRICS+ members, ranging from 10% to 100% reduction. For each scenario, the model computes a new equilibrium and reports changes in macroeconomic and sectoral indicators relative to the benchmark equilibrium. To validate the stability and robustness of the results, the Gragg multi-step solution algorithm is applied, and systematic sensitivity analysis is performed on key elasticity parameters within ±10% bands. The accuracy indices indicate strong numerical stability and internal consistency, confirming the reliability of the simulation outcomes.



Findings and Discussion

The results indicate that reciprocal tariff reduction leads to a positive and statistically meaningful increase in Iran’s real GDP across all scenarios. The magnitude of GDP growth rises as tariff reductions intensify, reaching approximately 0.8% in the 80–100% tariff elimination scenarios. This upward trend suggests that trade liberalization enhances allocative efficiency, reduces production distortions, and increases competitive pressure, contributing to higher overall productivity. However, diminishing marginal gains are observed beyond the 60% tariff reduction threshold, implying a nonlinear relationship between openness and efficiency gains.

Welfare, measured through equivalent variation, increases consistently across all scenarios. Welfare gains rise from approximately USD 520 million in the 10% tariff reduction scenario to more than USD 1.8 billion in the 60% reduction scenario, before stabilizing in higher-level liberalization scenarios. These welfare improvements arise mainly from lower consumer prices and enhanced access to imported intermediate and capital goods.

In contrast, the trade balance becomes increasingly negative as tariff reductions deepen. The trade deficit widens from around USD 336 million in the first scenario to over USD 6 billion in the full liberalization scenario. This widening deficit reflects a faster increase in imports—especially of industrial and capital-intensive products—relative to export growth. Nevertheless, the sectoral composition of trade flows exhibits dynamic and potentially favorable patterns. Industrial and agricultural exports increase substantially under deeper liberalization, rising from 2% and 1.8% in the mild liberalization scenario to more than 30% and 27% under full tariff elimination. This suggests that Iran’s productive capacity and competitiveness in selected industrial and agricultural subsectors can expand under more open trade conditions, provided structural rigidities are addressed.

On the consumption side, the reduction in tariff rates induces substitution effects favoring imported goods over domestic products in agriculture and industry, while the consumption of domestic services increases moderately. Government expenditure also shifts toward greater reliance on imported goods due to lower relative prices, suggesting potential public expenditure efficiency gains.

Sectoral value-added results indicate a reallocation of resources: the services sector experiences the highest positive value-added growth, while agriculture and industry experience slight reductions in value-added under full liberalization. This reallocation is consistent with economic theory, which predicts a shift of resources toward sectors with higher productivity and lower trade restrictions.



Conclusions and Policy Implications

The results of this study indicate that reciprocal tariff reductions between Iran and BRICS+ member states can lead to meaningful improvements in real GDP, welfare levels, and export performance, thereby supporting Iran’s long-term economic growth prospects. Nevertheless, the findings also reveal that the trade balance tends to worsen in the short run due to the more rapid expansion of imports relative to exports. This suggests that the potential benefits of trade liberalization are most effectively realized when tariff reduction is implemented in a gradual and phased manner, allowing domestic industries sufficient time to adapt, restructure, and enhance their productive capabilities. In this regard, a strategic sequencing of policy measures is essential, whereby tariff reductions are accompanied by targeted support for industrial upgrading and capacity development in sectors with export potential. Strengthening export-oriented value chains in both industry and agriculture can ensure that improved access to BRICS+ markets translates into durable gains rather than temporary trade fluctuations. At the same time, prioritizing investment in research, innovation, and technology development is crucial for enhancing competitiveness in high-value manufacturing activities.