Most cities have limitations by code of a percentage allowed per year. Usually 10%.
There's got to be more to this story, unrevealed facts that need to be reported. San Francisco does have stringent rent control, and there are many limitations against landlords hiking rent. There was a recent similar story a couple months ago in SF. A huge rent increase was warranted because of major work done on a building. If major work was done on this building, the improvements that tenants would enjoy would warrant a rent increase.