As long as you're playing the online version of the game, you are required to buy back stock over multiple decision rounds. You'll tank your stock price and only be able to buy back a small portion stock. It is a much wiser decision to buy your stock after a unusually good year and then sell it next year if your strategy is going to naturally result in a smaller ROE and EPS(and thus stock price.) Make sure to plan accordingly though. You want to buy back 100% of your stock by the final round