Inventory Model Suggests California Housing Market Has Stabilized

Historically, the inventory of unsold homes has been a good predictor of near-term price movements. I first wrote about the correlation between these two series in October of 2008. At the beginning of that year, the unsold inventory of single family homes in California had been equivalent to 14.3 months of supply. That was well above the historical median of 6.3 months, suggesting that 2008 would be a weak year.

In fact, 2008 turned out to be an abysmal year, largely because of the developing financial crisis. Home prices already had fallen 27% by August (the most recent month available at the time of my posting) and went on to record a 41% decline for the year.

I’ve updated my October 2008 chart through July of 2010. The chart compares the beginning-of-year inventory of single family homes in California to the change in median real price during that same year. As you can see, with the notable exception of 2008 and to a lesser extent, 2007, the beginning-of-year inventory has been a very good predictor of subsequent price movements.

The California housing market seems to have returned to equilibrium over the last year or so, at least as far as the balance between supply and demand. 2010 began with an unsold inventory equivalent to only 4.1 months of supply. That's somewhat lower than the historical median, suggesting that 2010 will actually see modest price increases. In fact, the median price of a single family home in California had increased by around 5% through the end of July (the most recent month available). Even with the recent drop in sales activity (following the expiration of the first-time buyer tax credit) the unsold inventory of homes in July was still only 5.8 months. That's in line with the historical median, suggesting that the near-term outlook for California home prices is reasonably good.

Note: I plan to do a similar analysis for San Francisco, but it will take some time. The unsold-inventory data that I had been using for San Francisco appears to be unreliable.