The Wikimedia Foundation (WMF) is the multinational organisation that owns and manages the Wikimedia platforms and the server infrastructure to run them. The organisation is responsible for managing the overall budgets and has funds available for Wikimedia affiliates. It also coordinates the foundation of national Wikimedia chapters and other Wikimedia movement affiliates.
Wikimedia Belgium is recognised as official Belgian Wikimedia chapter by the Wikimedia Foundation and gets funded by the Wikimedia Foundation through grants. In return Wikimedia Belgium has to publish annual reports (on activities and financial) and has to provide metrics and receipts for the costs/reimbursements Wikimedia Belgium has paid for.
The Wikimedia Foundation is together with the Wikimedia communities around the world and the movement affiliates part of the global Wikimedia movement.