Stock and suppliers

Why Stock Management Matters

Every business that produces or sells physical goods must manage its stock - the raw materials, work-in-progress, and finished goods it holds at any given time. Too much stock ties up cash and incurs storage costs; too little risks running out and failing to meet customer demand. Effective stock management keeps the right amount of stock available at the right time, at the lowest practical cost.

The Bar Gate Stock Graph

A bar gate stock graph (also called a stock control chart) plots stock levels over time and shows the key thresholds a business uses to manage reordering decisions.

The key elements of a bar gate stock graph are:

• Maximum stock level - The highest amount of stock the business is prepared to hold. Holding more than this wastes storage space and ties up cash unnecessarily.
• Minimum stock level (buffer stock) - The lowest amount the business will allow stock to fall to before it considers itself at risk of running out. It acts as a safety cushion against unexpected demand surges or delayed deliveries.
• Reorder level - The stock level at which a new order is automatically placed with the supplier. Set above the minimum to allow time for delivery before stock runs out.
• Lead time - The time between placing an order with a supplier and receiving the stock. The reorder level is set high enough that stock will not fall below the minimum during the lead time.
• Reorder quantity - The amount ordered each time - the difference between the maximum stock level and the minimum stock level (or a fixed quantity that brings stock back up to maximum).

The characteristic "gate" shape of the graph comes from stock falling steadily as it is used, then jumping sharply upward when a delivery arrives - a pattern that repeats in regular cycles.

Just-In-Time (JIT) Stock Control

Just-in-time (JIT) is a stock management philosophy in which materials and components are ordered and delivered only when they are needed for production - with no buffer stock held. The aim is to eliminate the cost and waste associated with holding large inventories.

• Advantages: Eliminates storage costs; reduces waste from perishable or obsolete stock; frees up cash that would otherwise be locked in inventory; encourages close, collaborative relationships with suppliers.
• Disadvantages: No buffer stock means any supplier delay or demand surge can halt production immediately; requires very reliable, fast suppliers; works poorly in markets with unpredictable demand; the business is highly dependent on its supply chain performing perfectly.

JIT was pioneered by Toyota in Japan and remains widely used in automotive and electronics manufacturing. It requires excellent supplier relationships and highly accurate demand forecasting to work safely.

The Role of Procurement and Supplier Relationships

Procurement is the process of sourcing and purchasing the materials, components, and services a business needs. Effective procurement is about far more than finding the cheapest price - the quality of the supplier relationship affects the whole supply chain and, ultimately, the product delivered to the customer.

Key factors in supplier relationships and procurement decisions include:

• Quality - Materials and components of poor quality produce poor final products. A supplier that consistently delivers substandard inputs damages the business's own product quality and reputation.
• Delivery - Cost, speed, and reliability of delivery are all critical. A supplier that delivers late or inconsistently disrupts production schedules and may cause the business to miss customer orders.
• Availability - Can the supplier guarantee consistent supply in the quantities required? Shortages at the supplier end can halt production even when the business has done everything right.
• Cost - Price matters, but the cheapest supplier is not always the best. Hidden costs (returns due to quality failures, production delays, relationship management) must be factored in.
• Trust - A long-term, trustworthy supplier relationship enables collaborative working, flexible payment terms, and priority treatment during shortages. Trust is built over time through consistent, fair dealings on both sides.

Supply chain decisions have a direct impact on a business's costs, reputation, and customer satisfaction. A business that sources cheaply from unreliable suppliers may save money initially but risks far greater costs when things go wrong.