The above picture shows that the inventory turnover of Amazon and Apple is 10 and 59 respectively (cost of goods sold of digital content/downloadable products are excluded). From the face value, Apple seems to be more efficient. Anyway, there is a reason for this. Apple Inc is now a marketing company with no manufacturing facility but Amazon is a distributor of general merchandise. It's pretty natural that Amazon has to keep more stocks then the inventory turnover is much lower.