< All Posts

Reducing COGS % and Improving Margin Through Range & Inventory Optimisation: Tackling Waste and SLOBs

Reducing COGS % and Improving Margin Through Range & Inventory Optimisation: Tackling Waste and SLOBs
Reducing COGS % and Improving Margin Through Range & Inventory Optimisation: Tackling Waste and SLOBs
Written by:
Mathew Tolley
Publish Date:
Jan 2026
Topic Tag:
Planning, Forecasting, S&OP and IBP

Ready to turn insight into action?

We help organisations transform ideas into measurable results with strategies that work in the real world. Let’s talk about how we can solve your most complex supply chain challenges.

Trace Logo

Reducing COGS % and Improving Margin Through Range & Inventory Optimisation

Waste and SLOBs Reduction

Cost of Goods Sold (COGS) is often treated as something largely fixed—set by suppliers, market conditions and scale. Yet for many organisations across Australia and New Zealand, COGS % creeps up over time not because unit costs increase dramatically, but because inefficiencies accumulate quietly across the range and inventory portfolio.

New products are added. Old ones linger. Forecasts become less accurate. Inventory ages. Waste increases. Slow-moving and obsolete stock (SLOBs) grows. Markdowns become routine. Expediting costs rise. Eventually, margin erosion is accepted as inevitable.

In reality, a significant proportion of COGS pressure is self-inflicted.

Organisations that systematically optimise their product range and inventory policies can materially reduce COGS %, improve gross margin and release working capital—often without renegotiating a single supplier contract.

This article explores how range and inventory optimisation directly impacts COGS, why waste and SLOBs are persistent challenges, and how organisations can tackle them in a practical, sustainable way. It also outlines how Trace Consultants helps organisations drive measurable margin improvement through structured, data-led approaches.

Why COGS % Creeps Up Over Time

COGS rarely deteriorates overnight. It erodes gradually through a combination of small decisions that, individually, seem reasonable.

Range Expansion Without Discipline

New products are often introduced to:

  • Respond to customer requests
  • Match competitors
  • Support promotions or growth initiatives

However, older products are rarely removed with the same rigour. Over time, ranges expand well beyond what demand can support efficiently.

The result:

  • Lower volume per SKU
  • Reduced forecast accuracy
  • Smaller production or purchase runs
  • Higher unit costs and logistics inefficiencies

Inventory Policies That Don’t Reflect Reality

Inventory parameters are often set once and rarely revisited. Safety stock, minimum order quantities and reorder points may no longer reflect:

  • Actual demand variability
  • True lead times
  • Service priorities

This misalignment drives both excess stock and stock-outs—each of which increases COGS in different ways.

Poor Visibility of Waste and SLOBs

Waste and SLOBs are frequently treated as:

  • “One-off write-offs”
  • “The cost of doing business”

Without clear ownership and ongoing monitoring, these losses repeat year after year.

Forecast Bias and Optimism

Forecasts often reflect what the business hopes to sell, rather than what demand signals support. This optimism flows directly into excess inventory, markdowns and obsolescence.

How Range Complexity Drives COGS Up

Range complexity is one of the most powerful—and underestimated—drivers of COGS %.

The Hidden Cost of Too Much Choice

Each additional SKU introduces:

  • Forecasting effort
  • Inventory holding cost
  • Planning variability
  • Procurement and logistics overhead
  • Risk of obsolescence

Even if a SKU is profitable on paper, it may still dilute overall margin by consuming capacity and attention.

Long-Tail SKUs and Margin Dilution

In many organisations, a small proportion of SKUs drive the majority of volume and margin. The long tail often:

  • Sells infrequently
  • Requires higher safety stock relative to demand
  • Contributes disproportionately to waste and SLOBs

Without active range management, these SKUs quietly erode performance.

Range Decisions Are Often Decoupled from Supply Chain Reality

Product decisions are sometimes made without full consideration of:

  • Minimum order quantities
  • Shelf life or expiry risk
  • Storage and handling complexity
  • Transport and packaging inefficiencies

When these costs are not visible at decision time, they show up later in COGS.

Inventory Optimisation as a Margin Lever

Inventory is not just a balance sheet item. It is a direct driver of COGS through waste, write-downs, handling cost and inefficiency.

Excess Inventory Increases More Than Holding Cost

Holding cost is only part of the story. Excess inventory also increases:

  • Damage risk
  • Expiry and obsolescence
  • Picking inefficiency
  • Space constraints and overflow handling
  • Discounting and markdown activity

All of these inflate COGS or reduce realised margin.

Stock-Outs Also Increase COGS

While counterintuitive, stock-outs can increase COGS by:

  • Driving expediting and premium freight
  • Forcing suboptimal substitution
  • Increasing small-batch purchases
  • Reducing production efficiency

Optimisation is about balance, not just reduction.

Waste: The Most Visible Symptom of Poor Alignment

Waste is one of the clearest indicators that demand, supply and inventory decisions are misaligned.

Common Drivers of Waste

Across industries, waste often stems from:

  • Over-forecasting
  • Poor promotion planning
  • Inflexible minimum order quantities
  • Long lead times combined with volatile demand
  • Range changes not reflected in inventory run-down plans

Waste is rarely caused by one bad decision. It is the cumulative effect of many small misalignments.

Why Waste Is So Hard to Eliminate

Waste persists because:

  • Accountability is diffuse
  • It is often discovered too late
  • Root causes are not systematically addressed

Without structural changes, waste reductions achieved one year often reappear the next.

SLOBs: The Silent Margin Killer

Slow-moving and obsolete stock is one of the most stubborn problems in supply chains.

What Creates SLOBs

SLOBs typically arise from:

  • Range rationalisation delays
  • Product lifecycle mismanagement
  • Forecast bias
  • Supplier constraints
  • Lack of clear exit strategies for underperforming items

Once inventory becomes slow-moving, options narrow quickly.

The True Cost of SLOBs

Beyond write-offs, SLOBs:

  • Occupy valuable warehouse space
  • Complicate picking and replenishment
  • Mask true demand signals
  • Consume management attention

Left unchecked, they distort planning decisions and perpetuate poor outcomes.

Connecting Range, Inventory and COGS %

COGS improvement requires seeing the system as a whole.

Range decisions affect:

  • Demand predictability
  • Purchase economics
  • Inventory requirements

Inventory policies affect:

  • Waste and obsolescence
  • Service levels
  • Expediting and handling cost

Together, they determine:

  • Gross margin
  • Cash tied up in stock
  • Operational efficiency

Treating these levers separately limits results. The biggest gains come from addressing them together.

Practical Approaches to Range Optimisation

Effective range optimisation is not about cutting aggressively. It is about making deliberate, evidence-based choices.

Segmenting the Range

Segmenting SKUs by:

  • Volume contribution
  • Margin contribution
  • Demand variability
  • Strategic importance

allows organisations to apply differentiated strategies rather than blanket rules.

Identifying Candidates for Rationalisation

Common indicators include:

  • Persistent low volume
  • High forecast error
  • Disproportionate waste or markdowns
  • Duplication or close substitutes

Importantly, decisions should consider total cost-to-serve, not just sales.

Managing Range Change Properly

Rationalisation without inventory exit planning simply creates SLOBs faster.

Effective programs include:

  • Clear sell-down strategies
  • Adjusted replenishment rules
  • Supplier engagement
  • Defined end-of-life processes

Inventory Optimisation Levers That Reduce COGS

Recalibrating Safety Stock

Safety stock should reflect:

  • Actual demand variability
  • True lead time performance
  • Service priorities by SKU or segment

Many organisations carry excess safety stock because parameters were never revisited.

Improving Forecast Quality Where It Matters

Not all SKUs require the same forecast effort.

Focusing improvement on:

  • High-value items
  • High-risk items
  • Items with high waste exposure

delivers far greater returns than chasing marginal gains everywhere.

Aligning Inventory Targets to Service Strategy

Different products justify different service levels.

Explicitly linking service targets to inventory investment:

  • Improves margin transparency
  • Prevents over-investment in low-impact areas

Governance: Where Most Initiatives Succeed or Fail

Many range and inventory initiatives start strongly and then fade.

Clear Ownership Is Critical

Successful programs clearly define:

  • Who owns range decisions
  • Who owns inventory targets
  • Who is accountable for waste and SLOBs

Shared ownership often results in no ownership.

Embedding Ongoing Review Cadence

Range and inventory optimisation is not a one-off project.

Effective organisations embed:

  • Regular range reviews
  • Ongoing SLOB monitoring
  • Periodic inventory parameter recalibration

This prevents issues from re-accumulating.

The Role of Data and Technology (Without Over-Engineering)

Advanced tools can help, but they are not a prerequisite for success.

What Matters Most

The biggest gains usually come from:

  • Better use of existing data
  • Clear metrics and definitions
  • Consistent decision-making

Technology should support decisions, not complicate them.

Avoiding the “Tool First” Trap

Investing in sophisticated optimisation software without fixing:

  • Data quality
  • Governance
  • Decision rights

often leads to underwhelming results.

How Trace Consultants Can Help

Trace Consultants works with organisations across Australia and New Zealand to reduce COGS %, improve margin and release cash through practical range and inventory optimisation.

Our approach focuses on sustainable improvement, not short-term fixes.

Diagnosing the True Drivers of Margin Leakage

We help organisations understand:

  • Where COGS is really being lost
  • How range complexity, waste and SLOBs interact
  • Which levers will deliver the greatest impact

This creates a clear, prioritised improvement roadmap.

Range Optimisation and Rationalisation

Trace Consultants supports:

  • SKU segmentation and performance analysis
  • Identification of rationalisation opportunities
  • Development of structured exit and transition plans
  • Governance frameworks to prevent re-expansion

All decisions are grounded in data and operational reality.

Inventory Policy and Parameter Optimisation

We help recalibrate:

  • Safety stock and reorder policies
  • Service level targets by segment
  • Inventory deployment across networks

The focus is on reducing excess without increasing risk.

Waste and SLOB Reduction Programs

Trace Consultants helps design and implement:

  • Waste tracking and root cause analysis
  • SLOB identification and disposition strategies
  • Preventative controls to stop recurrence

This turns waste reduction into an ongoing discipline.

Embedding Capability and Governance

Sustainable results require capability uplift. We support:

  • Role clarity and decision rights
  • KPI design and performance management
  • Review cadences and operating rhythms

This ensures improvements hold beyond the initial program.

Final Thoughts

Reducing COGS % and improving margin is rarely about one big initiative. It is about addressing the cumulative impact of range complexity, excess inventory, waste and SLOBs.

For organisations across Australia and New Zealand, the opportunity is significant:

  • Margin improvement without supplier renegotiation
  • Cash release without service degradation
  • Simpler, more resilient operations

The key is treating range and inventory optimisation as core commercial disciplines—not just supply chain housekeeping.

When organisations align product decisions, inventory policies and governance around a shared understanding of value and risk, COGS % comes down, margin improves and performance becomes far more predictable.

If COGS pressure feels persistent despite strong sales or procurement efforts, the answer may lie not in buying cheaper—but in carrying, managing and ranging smarter.

Ready to turn insight into action?

We help organisations transform ideas into measurable results with strategies that work in the real world. Let’s talk about how we can solve your most complex supply chain challenges.

Trace Logo