Account Management Vs Portfolio Management

I've always thought of Account Management as the relationship building team. They act as the point of contact for the customer and work diligently to ensure all of their needs are met.

This role can potentially overlap with some areas of Portfolio Management especially if the Account Manager is given responsibility for a customer's pipeline and product roadmap. Where the two differ, I think, is in that the portfolio manager might manage the aggregate pipeline of customers from multiple account managers (a broader portfolio). They also focus more on planning for the resource needed to execute on that portfolio, managing change to the portfolio and doing the necessary financial analysis and risk management at the higher level (portfolio v. project).

From a reporting perspective the Account Manager might have pipeline, project, budget, etc reports focused on a specific customer while the Portfolio Manager might have similar reports with less focus on the customer and more focus on a product or product line.

I could be wrong but that is how I understand the difference.