A team of San Francisco Chronicle reporters—Susie Neilson, Emma Stiefel, J.K. Dineen, and Lauren Hepler—conducted an in-depth analysis of the Bay Area’s property ownership records to trace the real ownership of the region’s rental properties.

“California doesn’t have hard-and-fast rules on how property owners identify themselves; large corporations, hedge funds and even wealthy families often purchase multiple homes through shell companies or trusts, shielding their names from ownership records.” To get more clarity, the team “used machine learning methods to parse the data and called on dozens of experts and additional data sources” to narrow down the 12 most influential property owners in the region. According to the authors, “We believe this is an unprecedented effort to uncover rental ownership and management networks across all nine counties in the region: Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano and Sonoma.”

The article lists the 12 owners and details about their properties, business practices, the demographics of their tenants, the geographic range of each owner’s properties, information about inspections and safety violations, eviction practices, and more. The authors note that “Even if the owner of your property isn’t on our list, you can learn more about who owns it by using our map of nearly 2.3 million Bay Area properties here.”