Vendor Managed Inventory and Lead-time

In B2B procurement, managing lead time effectively is crucial for ensuring seamless operations, especially when demand is dynamic and supply chain interruptions can have significant consequences. Lead time refers to the time from when an order is placed until the goods are delivered to the buyer. Several tools and arrangements are available to reduce lead time, ranging from standard lead time models to highly integrated systems like Vendor Managed Inventory (VMI).

Vendor Managed Inventory (VMI) is a supply chain strategy where the supplier of goods takes responsibility for managing the inventory of those goods in the buyer’s stockroom or warehouse. In this system, the supplier monitors inventory levels and replenishes stock automatically, ensuring that the buyer always has the right amount of stock on hand. But, When and, most important, Why vendor managed inventory.

Below is a detailed explanation of these tools, the relationship between them, and how they progressively shorten lead time:

Form Standard Lead time to VMI


Standard Lead Time

  • Definition: Standard lead time is the default delivery time provided by a supplier when an order is placed. It accounts for production time, order processing, packaging, and transit.
  • Characteristics:
    • Typically ranges from several days to weeks depending on the complexity of the product and geographical distance.
    • This lead time is often predetermined in a standard contract and does not account for any demand forecasting or order flexibility.
  • Limitations: While predictable, this lead time can be relatively long, especially if the supplier needs to manufacture the product from scratch after receiving the order.
  • Use Case: This is common for non-critical items or for one-off orders where there is no historical demand data or need for flexibility.

Forecasting and Supplier Integration

  • Definition: In this model, the buyer provides a demand forecast to the supplier. Forecasts are typically generated based on sales data, market analysis, and internal production needs.
  • Lead Time Impact:
    • Reduced Lead Time: When the supplier receives demand forecasts (e.g., monthly or quarterly), they can plan production and procurement in advance, significantly shortening the lead time.
    • This model allows for materials to be sourced or production to begin before the actual order is placed, reducing the time between order placement and delivery.
  • Key Tool: Collaborative Planning, Forecasting, and Replenishment (CPFR) – A collaborative approach where the buyer and supplier work together to forecast demand and schedule deliveries based on anticipated needs.
  • Use Case: Suitable for commodities or goods with predictable demand patterns, where the buyer has enough visibility into future needs to provide accurate forecasts.

Delivery Plan Agreement

  • Definition: A delivery plan agreement is a more structured approach where the buyer and supplier agree on a flexible delivery schedule, with predefined periods for adjustments (flexible and frozen periods). This arrangement often includes a rolling forecast and allows for variations in delivery quantities based on actual demand.
  • Lead Time Impact:
    • Shortened Lead Time: Because the supplier has already planned for deliveries based on agreed schedules, the actual lead time for deliveries can be significantly reduced.
    • The agreement may include shorter lead times for adjustments made within the flexible period, with the supplier holding pre-allocated inventory or having production capacity reserved for the buyer.
  • Key Tool: Rolling Forecast with Flexible and Frozen Periods – Buyers adjust their orders based on updated forecasts within the flexible period, while the frozen period guarantees the supplier stability for production and delivery planning.
  • Use Case: Ideal for items with semi-regular demand fluctuations, where both parties want flexibility in quantity adjustments but still need reliable delivery schedules.

Vendor-Managed Inventory (VMI)

  • Definition: In a VMI arrangement, the supplier takes full responsibility for maintaining inventory at the buyer’s site or at a nearby location. The supplier monitors the buyer’s inventory levels and autonomously manages replenishment.
  • Lead Time Impact:
  • Minimal Lead Time: Because the supplier holds inventory on or near the buyer’s premises, the lead time can be reduced to almost zero. Deliveries can be made within hours or days, depending on the specific arrangement.
  • This eliminates the need for order placement, as the supplier automatically replenishes stock based on real-time inventory levels or consumption data.
  • Key Tool: VMI and Consignment Stock – The supplier owns and manages stock at the buyer’s site, and the buyer only takes ownership of the inventory once it is consumed.
  • Use Case: Best suited for high-volume, fast-moving items or critical components that require immediate availability, such as raw materials in manufacturing or spare parts in maintenance operations.

Illustration of Lead Time Length and Tools

Tool/ArrangementDescriptionLead Time ImpactTypical Lead Time
Standard Lead TimeSupplier starts production after receiving the orderLong2–8 weeks (depending on product)
Forecasting & Supplier IntegrationBuyer provides regular forecasts, allowing pre-productionReduced1–4 weeks
Delivery Plan AgreementFlexible schedule with predefined frozen and flexible periodsShortened3–14 days
Vendor-Managed Inventory (VMI)Supplier maintains stock at the buyer’s site and replenishes automaticallyMinimal0–3 days
Table illustration typical lead times in comparison.

How These Tools Work Together to Shorten Lead Time

  1. Standard Lead Time: At the outset, the buyer receives a fixed lead time, often based on the supplier’s production and logistics schedule. This lead time can be relatively long, as the supplier typically starts production only after receiving an order.
  2. Forecasting & Supplier Integration: As the buyer begins sharing forecasts with the supplier, the supplier can plan production in advance, shortening the time needed to fulfill the order once it’s placed. This is particularly useful when demand is stable or predictable, allowing the supplier to align production with expected needs.
  3. Delivery Plan Agreement: By moving to a more structured delivery plan, the buyer gains even more flexibility to adjust orders within predefined parameters (e.g., adjusting quantities based on real-time needs). Since the supplier can plan deliveries in advance, the lead time becomes shorter than in traditional forecast-based models.
  4. Vendor-Managed Inventory (VMI): Finally, the shortest lead time is achieved with a VMI arrangement. In this setup, the supplier not only plans for future demand but also takes responsibility for maintaining stock at the buyer’s site or a nearby location. This virtually eliminates lead time since goods are readily available for immediate use.

Benefits of VMI

Reduced Costs

By implementing VMI, companies can reduce the cost of carrying inventory, as the supplier is responsible for maintaining optimal inventory levels. This reduces the risk of overstocking, which can lead to high carrying costs, or understocking, which can result in lost sales. As a result, companies can save money on inventory carrying costs, reduce inventory write-offs, and minimize stockouts. For example, Bosch Rexroth, a manufacturer of hydraulic and automation systems, implemented VMI, resulting in a 15% reduction in inventory costs.

Improved Inventory Management

VMI allows suppliers to monitor inventory levels and customer demand in real-time, which enables them to make informed decisions about replenishing stock. This ensures that the buyer always has the right amount of stock on hand, minimizing the risk of stockouts and reducing lead times. This results in improved inventory management, increased order accuracy, and enhanced customer service. For example, Walmart, the world’s largest retailer, implemented VMI, resulting in a 17% improvement in inventory turnover.

Enhanced Supplier-Buyer Relationship

VMI can lead to a more collaborative and strategic relationship between the supplier and buyer. As the supplier is responsible for managing inventory, they have a vested interest in ensuring that the buyer’s inventory is well-managed and optimized. This can result in a stronger supplier-buyer relationship, improved communication, and increased trust.

Increased Efficiency

VMI can also lead to increased efficiency in the supply chain. As the supplier is responsible for managing inventory levels, they can optimize delivery schedules and reduce lead times. This can result in a more efficient supply chain, reducing transportation costs, and increasing operational efficiency.

Implementing Vendor Managed Inventory (VMI): Essential Pre-Conditions Checklist

Implementing Vendor Managed Inventory (VMI) can be a transformative step towards optimizing inventory management and enhancing supply chain efficiency. However, successful implementation requires careful preparation and meeting certain pre-conditions. Here’s a checklist to consider when analyzing your supply chain for VMI readiness:

Clear Understanding of Demand Patterns

  • Historical Sales Data Analysis: Ensure access to accurate historical sales data to predict future demand.
  • Demand Forecasting Capabilities: Establish reliable forecasting methods to anticipate future sales.

Strong Supplier Relationships

  • Trust and Collaboration: VMI requires a high level of trust and open communication between the vendor and the buyer.
  • Track Record of Reliability: The supplier should have a proven record of fulfilling commitments and maintaining product quality.

Efficient Information Sharing Systems

  • Real-Time Data Exchange: Implement systems for real-time data sharing, like Electronic Data Interchange (EDI) or cloud-based platforms.
  • Transparency in Inventory Levels: Both parties should have visibility into current inventory levels, production schedules, and shipment information.

Technological Infrastructure

  • Inventory Management Software: Utilize advanced inventory management software capable of integrating with the supplier’s systems.
  • Automated Replenishment Systems: Have technology in place for automated order and replenishment triggers based on inventory levels.
  • Clear Contracts: Draft comprehensive agreements outlining responsibilities, liabilities, and conflict resolution methods.
  • Compliance and Regulations: Ensure that VMI practices comply with relevant industry regulations and standards.

Risk Management Strategy

  • Risk Assessment: Conduct a thorough risk assessment to understand potential challenges and their impacts.
  • Contingency Plans: Develop contingency plans for supply disruptions, demand fluctuations, or other unforeseen events.

Alignment with Business Objectives

  • Strategic Fit: Ensure VMI aligns with broader business strategies and goals.
  • Stakeholder Buy-In: Secure commitment from all stakeholders, including top management and operational teams.

Pilot Testing

Trial Runs: Consider conducting a pilot test with a limited range of products or a particular supplier to evaluate the effectiveness of VMI in your context.

Training and Development

  • Staff Training: Provide comprehensive training for staff involved in VMI processes.
  • Continuous Improvement: Establish mechanisms for ongoing evaluation and improvement of the VMI system.

Reflection Questions:

  • How will demand variability affect our VMI strategy?
  • What measures can we take to enhance trust and collaboration with our suppliers?
  • How equipped are we, technologically, to share and analyze real-time inventory data?
  • What legal considerations must we address in our VMI contracts?

Special contract considerations

When creating a Vendor Managed Inventory (VMI) contract, there are several special considerations that need to be taken into account. These include:

  • Clear Definitions: The VMI contract should clearly define the roles and responsibilities of both the supplier and buyer. This includes specifying which party is responsible for managing inventory levels, replenishing stock, and tracking performance metrics.
  • Inventory Ownership: The contract should also specify who owns the inventory in transit, as well as any excess or obsolete inventory. This is important to avoid any misunderstandings or disputes regarding inventory ownership.
  • Performance Metrics: The VMI contract should include performance metrics to measure the effectiveness of the VMI program. This includes metrics such as inventory accuracy, on-time delivery, and order fill rates. The contract should also specify the consequences for failing to meet these metrics.
  • Communication: The VMI contract should include communication protocols between the supplier and buyer. This includes how often the supplier will communicate inventory levels and delivery schedules, as well as how the buyer will communicate changes in demand or inventory needs.
  • Flexibility: The VMI contract should allow for flexibility to accommodate changes in demand, inventory levels, or other factors that may affect the VMI program. This includes the ability to adjust inventory levels, delivery schedules, or other program parameters.
  • Insurance: In a Vendor Managed Inventory (VMI) contract, the issue of insurance of goods stored should be addressed to ensure that both the supplier and buyer are adequately protected. The VMI contract should specify who is responsible for insuring the inventory while it is in transit or stored at the buyer’s location. Typically, the supplier is responsible for insuring the goods while they are in transit to the buyer’s location. Once the goods are delivered to the buyer’s location and placed in inventory, the buyer is responsible for insuring the goods. The VMI contract should also specify the type of insurance coverage required, such as liability insurance or property insurance. The contract should also include provisions for loss or damage to the inventory, including any exclusions or limitations on coverage. It’s important to note that insurance coverage is just one aspect of risk management in a VMI program. The VMI contract should also include provisions for managing other types of risk, such as supply chain disruptions, quality issues, and intellectual property disputes. By addressing insurance of goods stored in a VMI contract, both the supplier and buyer can have peace of mind that their inventory is adequately protected in the event of loss or damage.
  • Termination clause: Termination clauses in a Vendor Managed Inventory (VMI) contract are important to ensure that both the supplier and buyer have the flexibility to end the contract if necessary. The VMI contract should include specific provisions for termination, including the conditions under which either party can terminate the contract and the notice period required for termination. The termination clause should also address any financial obligations that may arise in the event of termination, such as payment for any inventory or services provided up to the termination date. The VMI contract should also specify any penalties or damages that may be assessed if either party breaches the contract. In addition to the termination clause, the VMI contract should also address what happens to inventory and equipment in the event of termination. The contract should specify the procedures for returning or disposing of inventory and equipment, as well as any costs associated with these activities. It’s important to carefully consider termination clauses when drafting a VMI contract, as they can have significant implications for both parties. By addressing termination clauses in the contract, both the supplier and buyer can have a clear understanding of their rights and responsibilities in the event of termination, which can help to minimize disputes and protect both parties’ interests.

In Summary – When and Why vendor managed inventory

Lead time in a B2B environment can be significantly reduced through strategic procurement arrangements, starting from standard lead times to more advanced tools like forecasting, delivery plans, and VMI. By progressively integrating these tools, companies can move from longer, fixed lead times to highly flexible, near-zero lead time setups that ensure they always have the right materials at the right time, optimizing supply chain performance and reducing risks of stockouts or production delays.

Implementing VMI is a strategic decision that requires meticulous planning and strong partnerships. By ensuring these pre-conditions are met, organizations can effectively leverage VMI to optimize inventory levels, reduce costs, and improve overall supply chain performance. Vendor Managed Inventory is a supply chain strategy that can benefit companies by reducing costs, improving inventory management, enhancing the supplier-buyer relationship, and increasing efficiency. Successful implementation requires strong communication and collaboration between the supplier and buyer, as well as the use of technology to monitor inventory levels and demand. 

Learn more about the operative processes in Learn How to Source’s basic package for the operative buyer role  and in the course RFQ template you can learn what should be included in a successful request to the market. The course describe the required information in order to collect correct and strong offers.

About Learn How to Source

Learn How to Source (LHTS) is an online platform based in Sweden, offering a range of procurement courses accessible globally. It serves as a community where procurement experts share their knowledge through online courses, designed for various experience levels from introductory to expert. Courses are concise, about 30 minutes each, and cover different aspects of procurement, tailored for different buyer roles. The courses focus on practical knowledge, presented by seasoned professionals, and include quizzes and certificates. They can be accessed from any device, emphasizing microlearning for flexibility and efficiency. More about LHTS in Swedish.

Note: Illustration to the blogpost “Vendor Managed Inventory and Lead-time” was created by CHAT-GPT on September 18, 2024.

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