Types of inventory

Inventory consists of the materials and products that a business holds to support its operations.

Categories of inventory

• Raw materials and components - Items bought from external suppliers and kept in storage until needed for manufacturing. These can be quickly transferred to production lines to respond to sudden rises in demand.
• Work in progress - Goods that are partially processed during manufacturing. The amount held depends on how long the production takes and the method used, with batch methods often leading to larger quantities.
• Finished goods - Completed products stored until they are sold or delivered. These are kept to showcase to buyers, handle unexpected demand surges, or prepare for periods of high seasonal sales.

The importance of inventory management

Effective inventory management helps businesses maintain efficiency by balancing the need for supplies against the risks of excess or shortages.

Reasons for effective inventory management

• Prevents shortages that could disrupt production or sales during unexpected demand changes.
• Avoids building up inventory that becomes outdated or no longer useful.
• Minimises waste caused by poor handling or unsuitable storage conditions.
• Keeps storage expenses and tied-up capital under control.
• Supports efficient purchasing from suppliers to maintain a steady flow of materials.

Costs of holding inventory

Holding inventory involves various expenses that can impact a business's profitability.

Key costs associated with inventory holding

• Opportunity cost - Money invested in inventory cannot be used for other purposes, such as repaying debts, acquiring machinery, negotiating supplier discounts through early payments, or generating interest. This cost rises when interest rates are high.
• Storage costs - Expenses for secure facilities, specialised environments like cooling systems, staff for security and handling, insurance for protection against loss or damage, and interest on loans used to finance the inventory.
• Risk of wastage and obsolescence - Inventory may spoil, become outdated due to changes in technology or trends, or get damaged during storage or transport, leading to reduced value or complete loss.

Benefits of holding inventory

Despite the costs, maintaining inventory provides advantages that can enhance business performance and customer satisfaction.

Advantages of maintaining inventory levels

• Reduces risk of lost sales - Ensures products are available when customers want them, offering variety and preventing buyers from switching to rivals.
• Supports continuous production - Avoids interruptions that would idle machinery and leave workers unproductive.
• Eliminates need for urgent supplier orders - Prevents additional charges for rush deliveries or special arrangements.
• Enables cost savings through bulk purchasing - Allows businesses to benefit from quantity discounts and reduced delivery frequency, lowering overall transport expenses.

Optimum inventory management

Achieving the right inventory level minimises total costs while meeting business needs. This involves finding a balance between holding too much and running out.

Determining optimum inventory levels

The optimum level is where total costs are lowest, as shown on an inventory cost graph.

Economic order quantity (EOQ)

EOQ represents the ideal order size for each type of inventory, varying by business and item.

It balances:

• Large orders - These reduce ordering and administrative expenses but increase storage and opportunity costs.
• Small orders - These raise ordering costs due to more frequent purchases but decrease storage expenses.

Factors influencing inventory decisions

Several elements affect how much inventory a business chooses to hold.

Key factors affecting inventory choices

• Storage capacity and costs - Limited space or high expenses may lead to smaller holdings.
• Nature of products - Perishable items or those at risk of becoming obsolete require careful management to avoid waste.
• Capital availability and opportunity costs - Businesses with limited funds may hold less to free up money for other uses.
• Production requirements - The manufacturing process influences how much raw material or work in progress is needed.
• Customer service expectations - High demand for quick delivery may require larger stocks of finished goods.
• Supply reliability and lead times - Unreliable suppliers or long delays encourage higher inventory to buffer against disruptions.