CIO vs CTO. Can someone give a simple breakdown?

Also consider context: in Financial Services, CIO = Chief Investment Officer, so CTO is default title to avoid confusion.

The distinction of external/product vs internal business operations is most prevalent in tech and tech-intensive companies.

In other (non-tech) orgs, the CTO might report into the CIO and be responsible for Infrastructure, Ops, Architecture and misc other functions.

In short CTO provides technology leadership to products and associated services versus CIO helps with technology strategy & execution towards business operations, business strategy and business processes.

CIO = internally focused on IT roadmap and strategy (i.e things employees will use for productivity, to conduct business, etc.). CTO = externally focused on technology roadmap (i.e. what customers will buy or use and are revenue generating), but often has the CIO roll up to them as well and therefore can be responsible for all technology.

The best differentiation I heard is that CTO is focusing on generating revenue through innovation and software development. CIO is focusing on saving cost through optimization of business processes and IT optimization.