The city also indirectly controls 200,000 units that are built and owned by limited-profit private developers but developed through a city-regulated process. Vienna adopted the latter approach in the 1980s, when it decided to collaborate with the private sector to build affordable housing rather than developing and owning more public housing. The city buys land deemed suitable for residential development and retains control over the type and nature of development. The city then solicits proposals from various private developers, which will build and retain ownership of the housing units.
