Here is an interesting thought: (Please don't misinterpret my meaning)
(A) In the 2008-2009 Financial Crisis, Real Estate Mortgage Bonds (MBS: Mortgage Backed Securities) started the Crisis that took down the economies of the world.
In baseball terms, Real Estate Mortgage Bonds were the "Lead Off Hitter" in the Crisis.
(B) It is very possible today that the Real Estate Industry could be giving us a Leading Indicator of future problems. Is it once again trying to be the Lead Off Hitter?"
Look at the 3 year chart of the Real Estate Builders and Material Suppliers ETF called NAIL.
Its down -74.85% since the January 2018 high!
[NAIL, 3 years, monthly candles]