copula function

The current research has been done with the aim of modeling the dependence of stock price carsh with emphasis on the conditional Copula-Garch function and its relationship with price bubbles based on the rational stock pricing structure in the Iranian capital market. In order to investigate and analyze the research questions, the data related to 30 companies admitted to the Tehran Stock Exchange for the period of 2010 to 2021 were extracted and used to test the research questions. In this research, first, the variable of price bubbles was estimated and extracted by estimating of the capital assets pricing models.Then, in order to model the correlation structure and stock return fluctuations of the sample companies, the multivariate GARCH model of dynamic conditional correlation approach with copula distribution was used. In the following, using the modeling output, the value at risk was calculated as a criterion for assessing the fall in stock prices. The results of the research showed that there is no significant relationship between stock price falls and bubbles based on the rational stock pricing structure. In other words, in the environmental conditions of our country, the condition of falling stock prices in line with the formed price bubbles is not based on rational stock pricing.