Public-Private Partnership (PPP) involves collaboration between government and private sector entities for the financing, construction, and operation of infrastructure projects or public services. Various models exist, differing in the allocation of responsibilities, risks, and ownership. - BOT (Build- Operate-Transfer): Private entity builds, operates for a concession period, then transfers to public authority. - BOO (Build-Own-Operate): Private entity builds, owns, and operates the facility. Ownership may or may not transfer later. - BOLT (Build-Operate-Lease-Transfer): Private entity builds, operates, leases the asset to the public authority, and then transfers ownership. - DBFOT (Design-Build-Finance-Operate-Transfer): A comprehensive model where the private partner is responsible for design, construction, financing, operation, and eventual transfer. All four models represent different arrangements under the PPP framework.