The 35,800-unit Fairfield County apartment market, long extremely tight and expensive due to suburban zoning that kept out multifamily housing, has undergone a stunning reversal. With more new units completing construction in 2015 than Reis has ever recorded here, the vacancy rate soared 190 basis points to 7.5%. It was up 80 basis points in the fourth quarter. The vacancy rate reached 7.9% in January 2016. Rents actually fell 0.3% by both measures in the fourth quarter. For all of 2015, the average asking rent was up 2.6% to $1,998 per month, and the average effective rent increased 2.7% to $1,946 per month. Overall rents increased 0.1% by both measures in January 2016.