Holding Costs

Holding costs, also called carrying costs or inventory carrying costs, are all the costs a business incurs to keep inventory on hand over a period of time. They include the cost of the money tied up in stock, storage space, handling, insurance, taxes, and the losses that occur when goods are damaged, stolen or become obsolete before they can be sold. Holding costs rise with the amount of inventory and the length of time it is kept, so they are one of the main reasons businesses try not to overstock.

Holding costs are a central idea in inventory management and operations, and they are weighed against ordering costs and the risk of running out of stock. The topic is also covered in the entry on the carrying cost of inventory; this entry concentrates on how holding costs are measured and used in decisions.

Holding costs are usually grouped into four categories:

• Capital costs, which are the interest paid on money borrowed to finance inventory, or the opportunity cost of cash that could have been invested elsewhere; this is often the largest component.
• Storage costs, including warehouse rent or depreciation, utilities, climate control, security and warehouse staff.
• Service costs, such as insurance on the stock, property taxes on inventory in some jurisdictions, and inventory management software.
• Risk costs, covering shrinkage from theft and errors, damage, spoilage of perishable goods and obsolescence when products go out of date or out of fashion.

Not all of these appear as a single line in the accounts. Rent, insurance and wages are recorded as operating expenses, and losses from shrinkage or write-downs pass through cost of goods sold, but the opportunity cost of capital is not recorded at all. For decision-making, managers therefore build an estimate from several sources.

Holding costs are commonly expressed as an annual percentage of average inventory value:

Here $\text{Average inventory value}$ is the average cost of stock on hand during the year and $\text{Holding cost rate}$ is the total of all holding cost components as a percentage of that value. Rates of 20 to 30 percent a year are often quoted as typical, though they vary widely by industry. A distributor with average inventory of $2,000,000 that estimates its cost of capital at 9 percent, storage at 7 percent, insurance and taxes at 2 percent and shrinkage and obsolescence at 6 percent has a holding cost rate of 24 percent, so its annual holding cost is $480,000. Reducing average inventory by $500,000 without hurting sales would save about $120,000 a year.

The best-known use of holding costs is the economic order quantity model, which finds the order size that minimizes the combined cost of ordering and holding:

Here $D$ is annual demand in units, $S$ is the cost of placing one order and $H$ is the holding cost per unit per year. If annual demand is 12,000 units, each order costs $75 to place and holding one unit for a year costs $2, the EOQ is the square root of 900,000, or about 949 units. Larger orders would save on ordering costs but raise holding costs by more.

Holding costs also explain the appeal of just-in-time manufacturing, which aims to receive materials only as they are needed. The trade-off is greater exposure to supply disruptions, which many businesses felt during the supply chain problems of 2020 to 2022, prompting some to accept higher holding costs in exchange for larger safety stocks.

Because holding costs tie up cash and reduce profit, they link inventory management directly to working capital and returns. Measures such as inventory turnover and days inventory outstanding help managers see whether stock levels are rising faster than sales. Some businesses reduce the capital cost by using inventory financing, vendor-managed inventory or consignment arrangements, which shift part of the burden to suppliers or lenders.