using days sales to measure inventory: a dangerous method

an example

I started out on Wall Street as a securities analyst covering the oil industry during the oil and gas boom caused by the second OPEC “oil shock” of 1978-80.  The sharp rise in prices (which today looks a bit ludicrous) from $7 a barrel to $14–implying a spike in gasoline prices above $.50 a gallon!!!–caused a huge increase in drilling for new deposits.

One key shortage element was the steel pipe used to line the well hole already dug, to prevent the hole from collapsing in on itself.  Without steel pipe to line the well you couldn’t drill.  So one of my standard questions during the interviews I did with company managements as I was preparing to write evaluations of their stock prospects was how much steel pipe they had on hand.  It was usually only two or three months’ worth.  It was never enough.  And the makers of the pipe were never able to ramp up capacity fast enough to meet demand, no matter how fast they put up new plants.

Anyway, one day I was talking to the CFO of a small exploration company in Texas.  When I had last talked with him, a couple of months before, he had said his company had about two months’ worth of pipe on hand.  I asked the question again.  He said, “We have a year’s worth of pipe on hand.”

I said, “You must have finally gotten a big shipment in.  How did you do it?”  He replied. “No.  Our drilling plans have changed.”

This was my first concrete indication that the commodity bust, which often follows a big boom, had arrived in the oilpatch.  What the CFO in my story meant to say was that prices had already fallen to a level where the wells his firm had been planning to drill were no longer economical and he could no longer get financing to carry out the projects.

the cash conversion cycle

This is a measurement of how much cash a company needs under current conditions to turn a dollar invested in working capital to make a new product back into cash.  It’s the sum of three parts:  the time it takes from purchasing raw materials until the sale of a final product is made + days credit extended to purchasers – days credit extended by suppliers.

In most cases, the key time element is the first element, the time in inventory.  Hence, the focus on inventory days.

supply and demand is much more important

…as my oil company example shows.

housing

Just as the situation of extremely constrained inventories can prompt one to draw the misleading conclusion that conditions will always be tight, the situation where inventories are massive can also be deceptive.  Housing in the US may well be a current case in point.

Despite the evidence that the housing market has been picking up in the Us for the past year, until just the past two or three weeks media reports have been strongly biased to the negative side.  One of the key figures being cited is the large inventory of unsold homes available for sale.

Two elements are wrong with this analysis, in my view:

–after many years of languishing on the market, and presumably not being maintained, I think it’s questionable whether all the dwellings counted in that inventory number are actually salable.  Maybe a quarter aren’t.

–even small changes in demand can make large differences in the days- sales measure.  For example, the latest Department of Commerce figures show that the inventory of new homes available for sale in the US has shrunk by 29% in the past year to 4.7 months.  Half of that decline is from builders creating fewer new homes.  The other half is from an increase in demand.  It wouldn’t take much more demand to push that figure into shortage territory.

I’m not saying that demand will increase (although I suspect it will).  I just want o point out that relying on days-sales figures for conclusions is potentially dangerous.

 

 

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: