On January 28, 2021, several brokers restricted transactions on Gamestop to position closing only. You are a consultant for a law firm and you have been asked to evaluate the effect of the restrictions. You need to select the relevant estimation window, event window, and post-event window. You need to come up with good control and estimate the Cumulative abnormal return for Gamestop.

You should first use the market model and then introduce multiple factors to estimate the Cumulative abnormal return What is your conclusion?