Project Portfolio Management (PPM) is the centralized management of the processes, methods, and technologies used by project managers and project management offices (PMOs) to analyze and collectively manage current or proposed projects based on numerous key characteristics. The objectives of PPM are to determine the optimal resource mix for delivery and to schedule activities to best achieve an organization's operational and financial goals, while honouring constraints imposed by customers, strategic objectives, or external real-world factors. The International standard defines the framework of the Project Portfolio Management 
PPM provides program and project managers in large, program/project-driven organizations with the capabilities needed to manage the time, resources, skills, and budgets necessary to accomplish all interrelated tasks. It provides a framework for issue resolution and risk mitigation, as well as the centralized visibility to help planning and scheduling teams to identify the fastest, cheapest, or most suitable approach to deliver projects and programs. Portfolio Managers define Key Performance Indicators and the strategy for their porfolio .
It is the determination of whether (and how) a set of projects in the portfolio can be executed by a company with finite development resources in a specified time. Fundamental to pipeline management is the ability to align the decision-making process for estimating and selecting new capital investment projects with the strategic plan.
The focus on efficient and effective deployment of an organization's resources where and when they are needed. These can include financial resources, inventory, human resources, technical skills, production and design. In addition to project-level resource allocation, users can also model 'what-if' resource scenarios, and extend this view across the portfolio.
The capture and prioritization of change requests that can include new requirements, features, functions, operational constraints, regulatory demands, and technical enhancements. PPM provides a central repository for these change requests and the ability to match available resources to evolving demand within the financial and operational constraints of individual projects.
With PPM, the Office of Finance can improve their accuracy for estimating and managing the financial resources of a project or group of projects. In addition, the value of projects can be demonstrated in relation to the strategic objectives and priorities of the organization through financial controls and to assess progress through earned value and other project financial techniques.
An analysis of the risk sensitivities residing within each project, as the basis for determining confidence levels across the portfolio. The integration of cost and schedule risk management with techniques for determining contingency and risk response plans, enable organizations to gain an objective view of project uncertainties.
In the early 2000s, many PPM vendors realized that project portfolio reporting services only addressed part of a wider need for PPM in the marketplace. Another more senior audience had emerged, sitting at management and executive levels above detailed work execution and schedule management, who required a greater focus on process improvement and ensuring the viability of the portfolio in line with overall strategic objectives. In addition, as the size, scope, complexity, and geographical spread of organizations' project portfolios continued to grow, greater visibility was needed of project work across the enterprise, allied to improved resource utilization and capacity planning.
Enterprise Project Portfolio Management (EPPM) is the practice of taking a top-down approach to managing all project-intensive work and resources across the enterprise. This contrasts with the traditional approach of combining manual processes, desktop project tools, and PPM applications for each project portfolio environment.
The PPM landscape is evolving rapidly as a result of the growing preference for managing multiple capital investment initiatives from a single, enterprise-wide system. This more centralized approach, and resulting 'single version of the truth' for project and project portfolio information, provides the transparency of performance needed by management to monitor progress versus the strategic plan.
The key aims of EPPM can be summarized as follows:
A key result of PPM is to decide which projects to fund in an optimal manner. Project Portfolio Optimization (PPO) is the effort to make the best decisions possible under these conditions.