It has always been a challenging question for financial analysts, investors and activists in the capital market that what factors affect stock price of companies. Furthermore, how such factors cause stock price fluctuations over time in the capital markets. Therefore, the aim of this research is to determine the effects of key contingent variables such as changes on equity, credit rating and assets price growth on stock prices volatility of petroleum companies listed on Tehran Stock Exchange (TSE). Financial data for the purpose of this study were collected from a sample of 91 companies during a period of eight years from 1392 till 1399 and research hypotheses were tested using the multivariate regression models and ordering panel data with fixed effects tests. Results showed a significant negative relationship between credit rating and stock price volatility. But, there was no significant correlation between changes on equity and stock price volatility. Also, there was not a significant relationship between assets price growth and stock price volatility.