The reasons for this vacancy rate are too numerous to discuss here, but there's a couple of explanations. Number one, wealthy offshore investors have been buying up new builds as a bolt hole in case the politics in their home countries goes haywire and they have a safe haven here in San Francisco in the event that they have to leave their home countries. Secondly, San Francisco's draconian rent control ordinances make being a landlord in San Francisco pretty unattractive