What is Portfolio Management?
Portfolio management selects and balances the organization's whole collection of projects and programs against strategy and constraints — doing the right work, where programs and projects do the work right. Its core activities: prioritization, capacity balancing, risk spreading, and killing weaker investments to feed stronger ones.
The hierarchy in one line: portfolio = choose; program = coordinate for benefits; project = deliver.
Worked example
An insurer's portfolio board reviews forty initiatives against three strategic pillars and a fixed engineering capacity. Twelve proposals score below the line and die before spending a dollar; two mid-flight projects get cancelled to fund a regulatory program that scores higher. Painful quarterly meeting — and the reason the company's strategy is a funding pattern instead of a poster.