Update: Watching existing home "for sale" inventory is very helpful. As an example, the increase in inventory in late 2005 helped me call the top for housing.



And the decrease in inventory eventually helped me correctly call the bottom for house prices in early 2012, see: The Housing Bottom is Here.



And in 2015, it appeared the inventory build in several markets was ending, and that boosted price increases.



I don't have a crystal ball, but watching inventory helps understand the housing market.



Inventory, on a national basis, was up 2.7% year-over-year (YoY) in August, this the first YoY increase since early 2015.



The graph below shows the YoY change for non-contingent inventory in Houston and Las Vegas (through September), Sacramento, and Phoenix (through August) and total existing home inventory as reported by the NAR (also through August).



Click on graph for larger image.



This shows the YoY change in inventory for Houston, Las Vegas, Phoenix, and Sacramento. The black line is the year-over-year change in inventory as reported by the NAR.



Note that inventory was up 33% YoY in Las Vegas in September (red), the third consecutive month with a YoY increase.



Houston is a special case, and inventory was up for several years due to lower oil prices, but declined YoY recently as oil prices increased. Inventory was up 6% year-over-year in Houston in September.



Inventory is a key for the housing market, and I am watching inventory for the impact of the new tax law and higher mortgage rates on housing. I expect national inventory will be up YoY at the end of 2018 (but still be somewhat low).



Note that inventory in Seattle was up 78% year-over-year in September!