Concession

Contract between the authority owning public service infrastructure (e.g. roads, power, water, telecommunications) to another party (usually private) allowing the latter to operate the public assets and retain the revenues for a specified period (usually 20-30 years). The contract typically requires the concessionaire to invest in extending or modernizing the assets, which revert to the authority at the expiry of the contract period. The operating company arranges its own finance, which does not appear on the authority´s account.
Other contractual models are a. rehabilitate, operate, and transfer. A private sponsor rehabilitates an existing facility, then operates and maintains the facility at its own risk for the contract period; b. rehabilitate, lease or rent, and transfer. A private sponsor rehabilitates an existing facility at its own risk, leases or rents the facility from the government owner, then operates and maintains the facility at its own risk for the contract period; c. build, rehabilitate, operate, and transfer. A private developer builds an add-on to an existing facility or completes a partially built facility and rehabilitates existing assets, then operates and maintains the facility at its own risk for the contract period.