Who is responsible for the business case development document?

The project manager is appointed after the business case is approved and is responsible for executing the project, not for creating the business justification.

Stakeholders provide input into the business case but are not accountable for producing or owning the document.

The project team executes the work defined by approved plans and does not develop the business case that precedes project initiation.

The project sponsor is the senior organizational leader who champions the project, owns the business case document, and is ultimately responsible for justifying the investment to the organization. The business case is developed before the project manager is formally assigned, reinforcing that sponsorship - not project management - drives this output.