An Empirical Analysis of Price Jump and Asymmetric Information in Tehran Stock Exchange

Deep understanding aboutthe impact of news and information on stock market is vital for analyzing and forecasting stock return. For this purpose, stochastic differential equations, such as geometric Brownian motion, geometric Brownian motion with jump and geometric Brownian motion with stochastic volatility have been used for simulation total price index. Using daily data of the total price index, index of the top 50 companies, and index of the 30 largest companies in Tehran Stock Exchange from 2009 to 2016, the following results were obtained:the Merton model has minimum error and geometric Brownian motion has maximum error to explain the behavior of price index. According to the log-likelihood criterion, geometric Brownian motion with stochastic volatility is preferred to geometric Brownian motion. The possibility of occurring jump in price index of large companies is more than that in the top 50 companies. During the mentioned period, the good news had the greatest impact on the total price index and price index of the top 50 companies.