The study looked at how different types of inventories held by manufacturing companies affect their profitability. They used data from 86 sub-sectors in Turkey from 2009 to 2021. The researchers found that converting finished goods and merchandise inventories into sales can increase net profits. However, holding onto raw materials and work-in-process inventories doesn't have a big impact on profits. The study also showed that during economic upturns, profit margins of manufacturing companies tend to decrease, likely due to competition.