What is a Performing Organization?
The performing organization is the enterprise whose people actually do the project work — the contractor building it, the vendor implementing it, the internal department delivering it. Distinct from the customer (who receives and accepts) and the sponsor's organization when work is contracted out.
The label matters for reading exam scenarios: whose processes govern, whose PMO audits, whose resources are negotiated — all follow the performing organization, whatever logo is on the building.
Worked example
A city (customer) hires an engineering firm (performing organization) to deliver a flood-defense scheme. The firm's methodology, quality system, and resource pool run the project; the city approves gates and accepts deliverables. When a scenario asks whose change process applies to a design revision — it's the firm's system, feeding the city's approval. Two organizations, two roles, one contract line between them.