In this article, learn about:
How manufacturers are optimizing their inventory for raw materials
How this affects both supply chain resilience and working capital for manufacturers
In the manufacturing world, the conversation around inventory has undergone a massive shift. For years, the gold standard was "lean", keeping as little on hand as possible to maximize efficiency. But recent global events, trade policy shifts, and a new era of tariffs have forced a fundamental rethink. Today, large manufacturers, such as those sourcing raw materials upstream to produce highly engineered products or finished goods, are facing a high-stakes balancing act.
How do you keep enough raw materials on hand to ensure production never stops, without tying up so much cash that you stifle your own growth? This guide explores why raw material inventory optimization has become a top-tier executive priority and how your organization can decide where inventory creates real resilience and where it simply hides planning weaknesses.
Related Reading: Raw Material Sourcing and Its Effects on Working Capital, Cash Flow, and COGS
What is Raw Material Inventory Optimization?
At its core, raw material inventory optimization is the process of deciding exactly how much stock to carry, where to hold it, and which specific materials deserve the highest level of protection based on business risk.
For a large manufacturer, this isn't just a warehouse exercise. Raw material inventory optimization is a cross-functional discipline that sits at the intersection of finance, operations, and procurement. It requires looking at inventory not as a logistical "must-have," but as a strategic financial investment. The goal is to ensure that your "safety stock" is actually making you safer, rather than acting as a buffer that masks poor supplier performance, delayed escalations, or weak internal planning.
Why Is This a Priority for Manufacturers Now?
The "just-in-time" (JIT) model that dominated the industry for decades has been tested by multiple waves of disruption. In response, many manufacturers have shifted to a "just-in-case" strategy, front-loading inventory and stockpiling parts to hedge against potential shortages.
However, this pursuit of resilience comes at a significant cost:
The cost of working capital: Elevated interest rates have made the financing of working capital significantly more expensive.
Profit squeezes: While the cost of energy and raw materials has increased, many manufacturers are only able to pass a fraction of these costs on to their customers, leading to a direct hit on margins.
Disuse risk: Carrying massive amounts of inventory increases the chance that materials will be written off before they can ever be used in production.
Recent data shows that a vast majority of manufacturers are feeling the direct impact of new trade policies, with many citing trade uncertainties as their primary concern.
Understanding the "Buffer Trap"
When supply lines feel vulnerable, the natural management instinct is to buy more. But unstructured stockpiling often leads to what is known as the "mix problem".
This happens when a company’s warehouses are bursting at the seams with materials that haven't been touched in years, while teams are simultaneously scrambling to find critical parts that were under-protected. This leads to expensive expedited orders and asset downtime that directly affects revenue.
Excessive buffers can also act as a distortion. They make it easy to ignore when a supplier is consistently late or when your internal forecasting and planning approach is the true root cause of your problems.
The Segment, Stock, and Plan (SSP) Framework
To avoid the pitfalls of blanket inventory mandates, more mature manufacturers are moving toward a framework known as "segment, stock, and plan." This approach helps organizations treat different materials with the specific level of care they require.
1. Improved Part Segmentation
Not all raw materials are the same or require the same handling. Some are easily substitutable; others have long lead times, concentrated supply, or outsized production impact. Effective optimization starts by categorizing parts based on three metrics:
Customer lead time: The time between receiving an order and the promised delivery date.
Supplier lead time: How long it actually takes for your materials to arrive.
Cutoff time: Calculated as the customer lead time minus the time required to manufacture and process the product.
If a material's supplier lead time is longer than your cutoff time, it must be "bought to stock" (BTS). If it is shorter, it can often be "bought to order" (BTO), which keeps your cash liquid for longer.
2. Increasing Algorithm Accuracy
Many legacy ERP systems rely on broad historical averages to predict demand, which often fails in a volatile market. A more advanced approach involves:
Limiting the forecast period: Only creating forecasts for time periods after the "known time,” or the window after which you can no longer change an order. This helps minimize assumptions.
Using daily increments: Moving from monthly to daily data segments can make stocking algorithms significantly more precise, potentially reducing shortages, in some cases by up to 50%.
3. Building Flexibility with Virtual Kits
In a low-volume, high-mix manufacturing environment, it can help to create virtual kits in your inventory system. These kits show you exactly what standard and specialized parts are needed for a specific customized product. This allows your team to instantly determine immediate production capacity based on available parts, rather than guessing.
Leveraging Technology for Real-Time Visibility
Targeted investments in digital tools remain essential for maintaining a competitive edge. The emergence of agentic AI and digital twins offers a new level of capability by autonomously sensing and mitigating supply chain risks.
These digital tools can provide value across the organization by:
Monitoring tier 2 risks: AI can look past your direct suppliers to see disruptions occurring further upstream due to trade policies or weather events.
Conducting "should-cost" analysis: By factoring in the raw material cost, shipping, and added tariffs, these tools provide an estimate of what a part should cost, helping procurement teams negotiate more effectively.
Simulating "what-if" scenarios: A digital twin allows you to simulate how your supply chain will perform before you implement a change, such as what would happen if cargo vessel supply was reduced by a quarter.
Related Reading: AI In Retail: How Artificial Intelligence is Reforming the Supply Chain
Organizational Alignment: Bridging Finance and Operations
Inventory optimization is a cross-functional discipline that requires a centralized approach to coordinate responses. Conflicts often arise because different functions view inventory through different lenses:
Maintenance and operations often manage for risk, wanting every part available at any time to avoid downtime.
Supply chain and finance manage for efficiency, wanting only the right part at the right time to protect cash flow.
Harmonizing these functions requires a multi-year roadmap that aligns incentives and improves team collaboration. Furthermore, as manufacturing becomes more tech-driven, you need a workforce that can handle advanced planning tools. This requires an adaptive "build, buy, or borrow" talent strategy: building core skills internally, buying external expertise for critical gaps, and borrowing temporary labor for fluctuating demand.
Building Structural Resilience
Short-term tactics, such as emergency shipments, can help identify gaps, but they don't build lasting resilience. True structural resilience requires long-term trade-offs, such as:
Diversifying the supplier base: Reducing reliance on a single source for critical components.
Dual-source, dual-design strategies: Using two different designs for the same product to provide the highest level of protection against raw-material shortages.
While these measures are expensive and the cost of keeping safety stock can be hard to justify when not in use, they are the new table stakes for navigating today's volatile market.
Resilience as a Competitive Advantage
By shifting away from uncoordinated stockpiling toward a segmented, data-driven approach, manufacturers can transform their inventory from a financial liability into a source of strategic resilience.
The goal is not a blanket mandate for lower inventory, but a sophisticated decision-making process that identifies which materials deserve protection and where buffers are truly worth the cash commitment. Organizations that prioritize this renewed strategic focus and continue to invest in visibility-enhancing technology will be best positioned to achieve sustainable growth and turn their supply chains into lasting competitive assets.
Ready to Turn Inventory Optimization Into a Competitive Advantage?
SPS Commerce Manufacturing Supply Chain helps manufacturers:
Strengthen end-to-end supply chain execution with better visibility, faster collaboration, and more reliable data flow across suppliers, partners, and customers.
Reduce friction, respond to disruption with confidence, and keep materials moving without overextending working capital.
Learn how Manufacturing Supply Chain with SPS Commerce can support a more connected, resilient supply chain.
