Mutual Effects of Tether and USD in Iran Based on VAR Model and Granger Causality

With the growing acceptance of cryptocurrencies, stablecoins have emerged as digital units of value designed to maintain a stable price, typically backed by one or more fiat currencies or other assets. Tether (USDT) is one such stablecoin, pegged to the U.S. dollar. Therefore, Tether’s exchange rate can serve as a meaningful benchmark for individuals seeking to preserve the value of their assets amid high volatility and inflation. This raises the question: does the digital trading of Tether influence the exchange rate of the U.S. dollar in Iran’s market, or is the free-market dollar rate—the primary reference for value—affecting Tether’s price? This study investigates the causal relationship between the exchange rates of Herat dollar, Sulaymaniyah dollar, and Tether on two major Iranian cryptocurrency exchange platforms: Nobitex and Wallex. The data covers the period from February ۲, ۲۰۲۴, to May ۱۴, ۲۰۲۴. Using a Vector Autoregression (VAR) model and the Granger causality test, we analyze these interactions across various time intervals (۱, ۱۵, ۳۰, and ۶۰ minutes) and different time segments including working hours, non-working hours, and market closure periods. The results indicate that during working hours, the Tether market predominantly follows the Herat and Sulaymaniyah dollar rates. However, in non-working hours, especially over short time intervals, Tether tends to influence the dollar rates. During complete market closure, the Tether prices on Nobitex and Wallex have a dominant role. These findings suggest that in the absence of active official markets, Tether can play a stabilizing role in the foreign exchange market. Consequently, policymakers may consider leveraging digital currency exchange platforms as a tool for exchange rate management.

کلیدواژه ها:

Tether (USDT) ، U.S. Dollar ، VAR Model ، Granger Causality ، Exchange Rate Policy ، Cryptocurrency