The 124,240-unit St. Louis apartment market had the biggest year for new supply since the 1980s, and the vacancy rate increased 100 basis points during 2017 to 5.6%. The rate was up 30 basis points in the fourth quarter. The rate was unchanged in January 2018. Rent gains slowed in 2017 from the prior strong pace due to rising concessions. The average asking rent increased 4.0% over the year to $891 per month, but the average effective rent was up 3.0% to $846 per month. The fourth quarter gains were just 0.4% and 0.2%, respectively. Overall rents increased 0.4% by both measures in January 2018.