The housing sector is highly cyclical and sensitive to economic and credit (interest rate) conditions. Below is a chart showing the development of the Housing Sector Index since the beginning of 2016. It is down 13.4% year-to-date while the S&P 500 index is up 6.2% YTD. 

Given the importance of home building/construction for the economy, the decline in stock prices of the companies that make up the index is of great concern. The index must hold its recent lows to alleviate somewhat the downside pressure.