This paper uses the DCC-GARCH and Value at Risk (VaR) model to analyze the fluctuation, linkage, and price volatility risk among coffee price series in the period of 2004 - 2020. In terms of the fluctuation, the study points out, the volatility of Vietnamese coffee price and the price of Robusta coffee in two markets were affected by two ARCH terms and GARCH terms at 1 percent level. Meanwhile, the coffee price of Brazil and Colombia is only impacted by the ARCH term. The linkage between Brazil and Colombia is the biggest. The average coefficient linkage among Vietnam with two main competitors is relatively small. In terms of price volatility risk, the price volatility risk of Vietnamese coffee is the smallest and the biggest risk is belonging to Brazilian coffee price. The results obtained would be a valuable reference for stakeholders, policymakers, coffee processing and exporting enterprises, and coffee farmers to clearly understand the fluctuation and linkage among coffee export price series, and thereby have appropriate and effective solutions and strategies in price volatility risk management to sustainable development.

In this article, the research team uses the VAR self-regression vector model to evaluate the impact of exchange rates on inflation and economic growth in Vietnam over the period 2005-2018. With six endogenous variables included in the VAR model: bilateral real exchange rate (Er), money supply (M2), exports (X), imports (IM), GDP at 2010 comparative prices (GDPR), the consumer price index (CPI) and the two exogenous variables, international price (Pw) and US Federal Reserve interest rate (Ifed), the research team examines the impact of exchange rates on endogenous variables in the model and considers the reaction of inflation and economic growth on various shocks. Based on the quantitative results, the research team will recommend some discus-sions to contribute for the improvement of Vietnam's macro environment, trade balance, inflation control, and economic growth support; implementing the goal of macroeconomic stability to suit the period of international economic integration and improving national competitiveness.

After financial crisis in 2008, the effect of crisis spread in the world. Many countries were affected quickly and others slowed in a particular mechanism. Using data of TEPIX from Tehran Stock Exchange and DJI from New York stock Exchange as the main indexes of these two markets, this paper reported strong evidence of TEPIX’s dependency on DJI after the crisis in a four-week delay. The index level series were non-stationary; therefore, we employed cointegration analysis and error correction vector autoregressions (VAR) techniques to model the interdependencies. To find the best lag time we used a heuristic method and the results surprisingly were the same as the result of applying a VAR model. The results support the hypothesis that financial stress was transmitted from the U.S to Iran primarily through trade and price channels.

The aim of this study is to investigate the changes in gold price and modeling of its return volatility and conditional variance model. The study gathers daily prices of gold coins as the dependent variable and the price of gold in world market, the price of oil in OPEC, exchange rate USD to IRR and index of Tehran Stock Exchange from March 2007 to July 2013 and using ARCH family models and VAR methods, the study analysis the data. The study first examines whether the data are stationary or not and then it reviews the household stability, Arch and Garch models. The proposed study investigates the causality among variables, selects different factors, which could be blamed of uncertainty in the coin return. The results indicate that the effect of sudden changes of standard deviation and after a 14-day period disappears and gold price goes back to its initial position. In addition, in this study we observe the so-called leverage effect in Iran’s Gold coin market, which means the good news leads to more volatility in futures market than bad news in an equal size. Finally, the result of analysis of variance implies that in the short-term, a large percentage change in uncertainty of the coin return is due to changes in the same factors and volatility of stock returns in the medium term, global gold output, oil price and exchange rate fluctuation to some extent will show the impact. In the long run, the effects of parameters are more evident.