Working in/for large companies, having a service oriented architecture in place, has it's own challenges. Especially when it comes to ownership of the complete enterprise service portfolio.
Imagine having hundreds or maybe thousands of infrastructural or enterprise services being used (consumed) anywhere/everywhere within your organisation. How to govern these succesfully? Sounds like a fair and easy question, but believe me it's not! Meaning; there is no simple, easy, single answer to that question. So let's approach it in small steps.
To key to success is to start with the first challenging question. Who feels the owner of these services? Should the full enterprise service portfolio be governed by a single IT unit within your organization? Can they manage that succesfully?
Can those services be categorized somehow within your organisation model? For example; can groups of services be assigned to specific business units? Let's say to human resource management, procurement, production or distribution? Which business objects are being represented within the specific service definitions? To whom belong these business objects? This might be a good start, to identify and create smaller service portfolio's. Let those business units feel responsible for their service portfolio in terms of their definitions, versioning, lifecycle and maybe even implementation.
I'm not saying there is one single solution to this topic, but this hopefully might give you some inspiration to make the right and necessary steps.