How is cyber security insurance managed in financial institutions; is it managed by ERM or CIO- cyber risk team?

All insurance managed by ERM but CISO team works with them on Cyber insurance 

What do you mean by "managed!" The CFO in many small to mid size companies deal with the brokers to get the quotes and defend budget concerns. Legal reviews that contract terms. The CISO should be involved in the security and data architecture reviews and questions. I also give strong input to the amounts needed, additional riders e.g. AI, etc. In the end it's an Enterprise Risk Management evaluation case to evaluate what risks to self- insure, etc. Remember that contracts may require certain limits but always check to see if the next higher band is more cost effective. Cyber liability insurance also helps with reputation management, forensics, etc so many departments and leaders need to be part of the process.

It depends on the organisation’s structure but for BFSI co-owned by CIO and CISO 

Its Managed by ERM