Studying the Asymmetric Effects of Exchange Rate on the Return of Selective Industries in Tehran Stock Exchange

Financial markets are sensitive to exchange rate fluctuations of the Iran’s economy. Changes in the foreign exchange market affect household, businesses, and government spendings. Exchange rate management policy helps stock market to be protected from the effects of exchange rates. As for investment strategies, investors can invest without considering the exchange rate in the short run investments, but exposure to asymmetric exchange rate is very important in long run.
This study explores the asymmetric exchange rate exposure of stock returns building upon the capital asset pricing model (CAPM) framework, using monthly returns of Iranian industry indices. In accordance with the existing literature, industry returns are subject to lagged exposure effects, but the asymmetries vary across industries, which could be due to the discrepancies of trade balance and ownership of certain industries.
Furthermore, the dynamic multipliers depict that industry returns quickly respond to changes in the exchange rate and correct the disequilibrium within a short time, making the long run exposure to be symmetric or very small (Cuestas & Tang, 2015). The main aim of this study is, hence, to investigate the asymmetric exchange rate exposure of stock returns in the Iranian stock market at the industry level. Specifically, we introduce the conventional CAPM for measuring exchange rate exposure. We construct the dynamic nonlinear model to investigate both the long run and short run asymmetric exposure effects, which is carried out by means of estimating a nonlinear autoregressive distributed lag (NARDL) model introduced by Shin and Greenwood-Nimmo (2014).
Building upon the CAPM structure, this paper contributes to a growing literature on the analysis of exchange rate exposure of Iran's stock market on the following grounds. First, compared to linear regression models, the NARDL model demonstrates its competence and efficiency in estimating the exchange rate exposure. The disparities in the exposure effect depend on the ownership of these companies and the expansion of their global operations. Second, industry returns strongly and quickly respond to exchange rate changes in the very short run, while most of the long run exposures are symmetric or very small.
In fact, this paper studies the effects of positive and negative shocks of exchange rate on the return of various industries in stock market based on CAPM model and NARDL approach to estimate parameters during the period of April 2012 to March 2015.
To evaluate the efficiency of asymmetric effects of exchange rate on active industries in Tehran stock market, first exchange rates decompose to positive and negative shocks and then its asymmetric effects on stock market is analyzed using NARDL model. To do it, we use the Wald test for the symmetry or asymmetry effects of positive and negative exchange rate on return of active industries in the short run and long run. The results indicate that most industries of stock market are under the influence of positive and negative shocks of exchange rate and these effects are different for industries. Hence, the effects of positive and negative exchange rate shocks for the industries such as agriculture, textile, rubber, engineering, leather, communication, steel products, radio, chemical materials, and multi-disciplinary industries are symmetric while the effect of exchange rate shocks on return of industries like bank, automobile, basic metals, publishing and printing, electrical devices, computer , tool medical, cement, finance, non finance, investments, paper, non-metallic minerals, and machinery industries are asymmetric in short run, and for industries of ceramic tiles, they are asymmetric in the long run. Additionally, in industries like mass production, oil, transport, coal, drugs, wood, sugar, food ingredients except sugar, they are asymmetric in the short run and long run.
Thus, the results of this study can be useful for investors and shareholders in predicting the short and long term effects of exchange rate shocks on the stock prices.
Therefore, it can be argued that sudden shocks exchange rate can affect about 70 percent of returns of active industries in Tehran Stock market. Therefore, avoiding sudden shocks and maintaining relative stability in exchange market are the main suggestions for policymakers. Also, given that the exchange rate shocks are exogenous variables for firm managers, investors should further evaluate the performance of companies and their profitability, and consider long run vision in analysis and making decisions.