"The City by the Bay is going through one of its worst housing shortages  in memory. With typical high demand intensified by a regional boom in  tech jobs, apartment open houses are mob scenes of desperate applicants  clutching their credit reports. The citywide median rental price for a one-bedroom is $2,764 a month, but jumps to $3,500 in trendy areas." 
"One reason for the shortage? Me.I’ve recently joined the ranks of San Francisco landlords who have  decided that it’s better to keep an apartment empty than to lease it to  tenants. Together, we have left vacant about 10,600 rental units.  That’s about five percent of the city’s total — or enough space to  house up to 30,000 people in a city that barely tops 800,000...
"To stabilize rents and prevent eviction abuses  that are typical when housing is scarce, the city developed some of the  nation’s toughest housing policies. Rent-control ordinances, for  example, sharply limit rent increases after the initial lease for most  housing constructed before 1979. As a result, many leases morph into lower-rent tenancies for life, subsidized by landlords, even when the tenants are wealthy. 
"In addition, a complex legal structure has been created to make evictions for just cause extraordinarily difficult.        
 
