If I was the CISO of a publicly-traded company, I would implement protections such as intrusion detection systems and firewalls on my systems to ensure availability. An intrusion detection system monitors network traffic. this system will allow workers to closely analyze traffic over a network to find vulnerabilities or abnormal traffic patterns. An IDS alerts workers when a network intrusion may have occurred which allows ample response time for incident response.
A firewall will act as a filter between my systems and the internet. With a firewall, I will be able to customize who or what gets in and what gets out. Along with firewalls and Intrusion detection systems, there will be role-based access control which allows administrators to manage roles and users separately.