6. Conclusions
The core principle of concepts such as ‘just-in-time’ or ‘zero inventory’ is that inventory reflects waste and should be
eliminated, causing productivity to rise. Nevertheless, our empirical results suggest that inventory holding costs
money but is not always a disadvantage, because inventories do have benefits as well. Hence, the notion ‘less
inventory is better’ is empirically refuted. Interpreting financial performance as a function of inventory holding, our
results suggest a positive relationship between inventory holding and financial performance, i.e. those firms with the
lowest inventory also show the worst performance (and vice versa). Understanding inventory as a function of
financial firm performance, our results suggest a positive relationship between inventory holding and financial
performance. Low-performing firms carry the least inventory, while high- and medium-performing firms have more
than twice as much inventory in stock on average. In short, our empirical results do not support the zero inventory
management paradigm.
For managers, these findings may be relevant for several reasons. First, and most importantly, managers should
not believe in the zero inventory paradigm per se. Second, managers should not expect to improve their firm
performance simply by reducing inventories; instead they will risk the opposite. Third, in order to find the optimum
inventory level, managers are well advised to apply well-known operations research techniques. Fourth, managers of
financially stable firms may choose between investments in inventory holding or modern supply-chain techniques.
Finally, managers of firms in financial trouble have to face the fact that reducing inventories may help them to
increase short-term liquidity in hard times, but this will not help the firms in better times, when they need inventories
to run production and serve their customers. As the recent financial crisis showed, many firms went bankrupt when
the recession was over. Firms which had discharged their inventories during the recession suddenly did not have
sufficient liquidity to fill up their inventories when business cycles moved upwards again.
Our findings might also give a direction for further research, seeing inventory not so much as a predictor of
financial performance but as what it mainly is: a ‘buffer’ which allows firms to carry out several processes and
functions well, for instance achieving smooth production levels, shifting production to periods in which production
costs are expected to be relatively low, avoiding costly setups or multiple orders and shipments, or as a precaution
against stock-outs. It may also be interesting to analyse the relationship between inventory holding and financial
performance for different stages of the supply chain. On a raw materials level, the worst case scenario for justin-
time or zero inventory may result in a complete production system coming to a standstill. From a finished goods
point of view, however, high inventories can result in obsolescence and cause component devaluation. From a
strategic point of view it might be interesting to investigate whether innovative companies with higher profit margins
do not (have to) take care of inventories as much as companies following a cost-leadership strategy with lower
margins. Nevertheless, further research is necessary to gain more insight into the causal logic of the relationship
between inventory holding and firm performance.