After sitting on the sidelines earlier this year, when its stock price was beaten down a bit and pricing for MOBs was too high for its liking, Toledo, Ohio-based Welltower (NYSE: WELL) has come roaring back with acquisitions and investments totaling billions of dollars.

In past metro highlights we’ve talked about growth markets with lots of construction activity, interesting markets with innovative health systems, metros with the highest sales volume, but what about the tightest markets? The ones with the highest rent growth, the most expensive pricing and the lowest vacancy? Flipping through our Metro Rankings report, San Francisco clearly fits the bill.