Stochastic Langevin equation can be used to model real world scenarios using the predefined parameters. It helps in describing a    system which evolves under deterministic as well as fluctuating forces. In the case of stock market, they can be moving under a macroscopic economic growth but undergoes short term random fluctuations. The driving force is the economic growth which again depends on the quantities like corporate earnings, GDP growth, inflation as well as bond yields. We can use these quantities as the driving force along with the random variable we add in the Langevin equation.