If I were the CISO for a publicly traded company, I would implement some protections to ensure my systems’ availability, which would be making a risk management strategy.  That would consist of figuring out my clients and the most prominent risks associated with them.  Making sure my company’s assets are always right and having insurance.  I would also have updated security precautions to protect all systems.  At the end of the day, if I were CISO, I would implement more preventive measures but also know how to handle situations if they happen.  I would do this and have these precautions and situation training to keep the availability and company in place and tip-top shape.  To stay in business and be a reliable company for customers.