Cybex Retail AI
CYBEX RETAIL AI / EXECUTIVE EBOOK

Merchandise Planning
& Inventory Optimization

An integrated retail operating framework

01  ASSORTMENTPlan
02  LOCALIZESize & Color
03  FORECASTDemand & Stock
04  OPTIMIZEService & Investment
Lazar Belos Author  |  Cybex Retail AI & Analytics Advisory  |  August 2026
CYBEX RETAIL AI/CONTENTS

Contents

A connected operating model from assortment intent to executable stock policy.

THE OPERATING CONNECTION

Assortment planning defines what should be offered. Size and color management localizes the offer. Stock forecasting projects demand and inventory. Optimization converts those projections into service, investment, replenishment and turnover decisions.

RETAIL MERCHANDISE MANAGEMENT PAPER

Merchandise Assortment Plan

Financial targets, assortment architecture, breadth, depth, store ranging, lifecycle, receipts and open-to-buy

Purpose

A high-level operating design for translating customer demand and financial objectives into an executable apparel assortment by class, channel, store cluster, style, color, size and forward retail week.

Cybex Retail AI & Analytics Advisory

August 2026 | Illustrative design paper

Executive summary

A Merchandise Assortment Plan, or MAP, defines what the retailer intends to sell, where it will be ranged, when it will arrive, how much depth it will receive and how the investment will achieve sales, gross margin, service and turnover objectives. It connects the financial merchandise plan to the style-color-size decisions that purchasing and allocation must execute.

Core principle

Plan the customer offer and its economics together. Breadth, depth, timing, price, margin, presentation, replenishment and exit must reconcile to one approved demand, receipt and inventory plan.

MAP decisions

  • Financial envelope: sales, gross margin, markdown, receipts, stock investment and inventory productivity.

  • Assortment architecture: roles, choice counts, price points, brands, attributes, colors and size coverage.

  • Market localization: channel, climate, store cluster, capacity, customer profile and local demand.

  • Time phasing: launch, build, peak, replenishment, winddown and exit by forward retail week.

  • Execution: initial buy, chase reserve, receipt windows, DC allocation and exception management.

Relationship to the companion papers

Companion paper Contribution to MAP
Apparel Stock Forecast Supplies normalized, seasonal, forward-week demand and confidence.
Apparel Size & Color Management Translates choices into color shares, size curves and constrained runs.
Retail Stock Optimization & Optimum Stock Sets service, safety-stock, WOS and investment policies after ranging.

Table 1. MAP coordinates the commercial plan; the companion modules supply detailed operating logic.

1. MAP operating model

Enterprise
financial plan
Department / class
merchandise plan
Channel / cluster
assortment targets
Style / color / size
choice plan
Purchase +
allocation

Top-down targets and constraints flow right to left; bottom-up choices, productivity and feasibility flow left to right.

Figure 1. MAP requires top-down financial control and bottom-up choice-level feasibility.

Planning cycle

  • Set enterprise and category financial targets by channel and time period.

  • Translate demand into assortment roles, choice counts, price points and planned depth.

  • Range choices to clusters and stores using eligibility, demand, capacity and strategic rules.

  • Build the initial and replenishment receipt plan within lead-time and open-to-buy constraints.

  • Reconcile bottom-up style-color-size totals to approved sales, margin, receipt and stock plans.

  • Approve a version, execute it, then reforecast and govern exceptions in-season.

Operating output

An approved MAP version should identify the merchandise hierarchy, market scope, forward weeks, financial targets, assortment roles, ranged choices, unit depth, receipt timing, store participation, scenario and owner.

2. Merchandise hierarchy and planning grain

The merchandise hierarchy provides financial control; the choice hierarchy provides execution. Planning must support aggregation and drill-down without confusing a style, a style-color choice and an inventory SKU.

Level Example Primary MAP decision
Enterprise / channel Retail, ecommerce, wholesale Investment, sales and margin envelope
Department / class Women / knitwear Financial targets and assortment role mix
Subclass / attribute Cardigans / cotton / opening price Choice count, price point and attribute gaps
Style Rib cardigan Design choice, lifecycle and supplier commitment
Style-color choice Rib cardigan - navy Color breadth, initial depth and store participation
SKU Rib cardigan - navy - M Size demand, purchasing and allocation
Location / cluster Urban A cluster / Store 101 Ranging, capacity and localized depth
Forward retail week Launch week through exit Sales, receipts, inventory and action timing

Table 2. Recommended hierarchy and the decision governed at each level.

3. Financial merchandise plan

A time-phased Assortment Plan aligns sales, receipts and stock 0 200 400 600 Winddown begins Terminal stock floor: 56 units Forward retail week Planned sales units Projected ending stock Planned receipts

Figure 2. A time-phased plan identifies receipt needs, peaks, winddown and terminal-stock exposure.

Measure Definition / formula MAP use
Net sales Gross sales less returns and discounts, using the retailer's governed definition Demand and revenue target
Gross margin Net sales - cost of sales; GM% = GM / net sales Profit and vendor / price-point balance
Markdown Planned permanent and promotional price reduction Exit cost and demand shaping
Receipts Merchandise received in the planning period Supply and cash commitment
EOM stock BOM stock + receipts - sales - markdowns +/- adjustments, at consistent retail basis Ending investment and exit risk
Inventory turns Annualized cost of sales / average inventory at cost Inventory productivity
Sell-through Cumulative unit sales / (unit sales + ending on hand) Lifecycle productivity

Table 4. Core MAP financial measures; valuation bases must remain consistent.

Financial discipline

Do not sum monthly EOM stock as though it were flow. Use average inventory, ending inventory, turns, WOS and sell-through to evaluate stock productivity.

4. Assortment architecture: breadth and depth

Breadth and depth should vary by assortment role Core basics Proven seasonal Destination Key colour Fashion Exit Test capsule Long tail Narrow breadth / deep stock Broad breadth / deep stock Narrow breadth / shallow stock Broad breadth / shallow stock Relative assortment breadth Relative units per choice

Figure 3. Core choices normally receive deeper stock; fashion, test and long-tail choices require controlled depth.

Breadth is the number of customer-visible choices. Depth is the inventory committed behind each choice. In apparel, a choice commonly means style-color; the SKU count expands further through sizes and locations.

Assortment role Breadth posture Depth posture Typical treatment
Core / carryover Narrow to moderate Deep High participation, replenishment and service protection
Proven seasonal Moderate Moderate to deep Time-phased receipts and early chase
Fashion / key trend Moderate to broad Controlled Short lifecycle, confidence-based depth
Test / capsule Very narrow Shallow Limited clusters; explicit learning objective
Long tail / extended Broad selectively Very shallow Digital or hub inventory; store access through network
Exit Contracting No new depth Transfer, markdown and assortment removal

Table 5. Illustrative breadth-depth policy by assortment role.

Choice economics

Each additional style-color choice creates presentation, size-run, safety-stock, operational and markdown cost. Add breadth only when incremental demand and margin exceed the fragmentation cost.

5. Store clustering, range matrix and capacity

Illustrative range participation by store cluster and assortment role
CoreProven
seasonal
Key fashion Extended
colour
TestLong tail
A cluster 100% 100% 100% 85% 60% 35%
B cluster 100% 100% 90% 65% 35% 15%
C cluster 100% 90% 70% 40% 15% 5%
Digital / hub 100% 100% 100% 100% 85% 70%

Figure 4. A range matrix controls where choices are eligible before depth and allocation are calculated.

Store clustering reduces noise and gives merchants an understandable way to localize the assortment. A store may inherit its cluster range and then receive governed overrides for climate, local demand, strategic role, capacity or fulfilment capability.

Range control Application
Store / cluster ABC Prioritizes productive or strategic locations without assuming every A store needs every choice.
Store index Scales demand and depth relative to the normalized average eligible store.
Capacity Limits active styles, color choices, SKU facings and units.
Climate / market Controls seasonal timing, fabric, color and localized attributes.
Fulfilment role Distinguishes selling store, showroom, hub and digital inventory.
Override Requires reason, owner, expiry and expected outcome.

Table 6. Range eligibility precedes purchasing and allocation.

Capacity rule

When space is constrained, protect productive core choices, highest-selling colors and locally relevant sizes before adding lower-confidence breadth.

6. Lifecycle and seasonal phasing

Lifecycle phasing changes the permitted receipt and stock profile Launch window Winddown window 0 30 60 90 Retail week Core / carryover Seasonal Fashion / launch Exit exposure if receipts continue

Figure 5. Lifecycle determines when receipts are useful and when additional stock becomes exit exposure.

Phase MAP decision Inventory posture
Pre-season / commit Approve choices, total demand, supplier capacity and initial receipt Build only enough to support launch and lead-time risk
Launch Measure availability, adoption, color and size response Protect presentation; do not overreact to first-day noise
Build / peak Release chase, replenish winners and rebalance stores Use updated forecast and service policy
Mature Reduce open commitment and review slow choices Hold productive depth; release excess
Winddown Shorten range, stop replenishment and consolidate stock Sell through by exit; avoid restoring full runs
Exit Markdown, transfer, return or remove No safety stock after sellable life

Table 7. Lifecycle-specific MAP controls.

Receipt phasing principle

Commit early only for demand that cannot be served through later receipts. Reserve flexible capacity for forecast error and early selling evidence. Long lead-time goods require earlier decisions and a larger scenario envelope; short lead-time goods can use chase replenishment to reduce initial risk.

Terminal-stock rule

A plan is incomplete unless projected ending stock is visible through the exit week. Remaining units become transfer, markdown, return-to-vendor or carryover exposure.

7. Choice productivity, ABC and option thresholds

Choice productivity reveals where breadth adds value or fragmentation 0 50 100 A: first 10% B: next 85% Choice rank Cumulative contribution (%)

Figure 6. Productivity typically concentrates in a smaller set of choices; ABC helps prioritize service and depth.

Choice productivity should influence depth, participation and replenishment, but it should not be the only design input. Strategic brands, opening price points, visual statements, new concepts and destination items may require controlled overrides.

Class Illustrative contribution MAP treatment
A First 85% of governed sales or margin contribution Protect availability, broadest justified participation and chase capacity
B Next 10% Balanced participation, depth and replenishment
C Final 5% Selective range, shallow depth or network availability
Strategic override Outside normal rank Explicit role, investment cap, owner and test period
Exit Lifecycle override No new buy; consolidate and clear

Table 8. Cybex 85/10/5 ABC convention applied to assortment choices.

Choice thresholds

  • Minimum expected sales and margin per choice

  • Minimum weeks at full-price selling before evaluation

  • Maximum inventory and markdown exposure per test

  • Minimum presentation and complete-run requirement

  • Capacity and cannibalization test before adding breadth

8. Color and size planning within MAP

MAP approves the style-color choices and the market participation. The detailed size curve and color-size stock policy then translate each approved choice into SKU demand, purchase quantities and store allocation. This prevents financial choice counts from hiding unproductive colors or broken core sizes.

Planning layer MAP responsibility Detailed operating module
Style Role, lifecycle, price, total demand and supplier Forecast and purchasing plan
Color Choice approval, share, participation and initial depth Color WOS, forecast and lifecycle
Size Run eligibility, curve source and presentation minimum Store / cluster size index and safety floor
Store / cluster Range, capacity, demand index and fulfilment role Allocation, replenishment and transfer
Forward week Launch, receipt, replenishment and exit windows Forecast, stock projection and WOS

Table 9. MAP owns the commercial choice; companion modules provide SKU-level operating logic.

Illustrative style-color-size plan

Color role Share Store participation Size run Initial posture
Core navy 34% A/B/C + digital XXS-XXL Full curve; deepest depth
Core black 28% A/B/C + digital XS-XXL Full commercial curve
Seasonal green 18% A/B + digital XS-XL Shortened tail sizes
Fashion coral 12% A + selected B S-XL Controlled test depth
Extended cream 8% Digital / hub XS-XXL Network availability

Table 10. Illustrative choice plan; percentages and runs are examples only.

Control total

Color shares reconcile to 100% of the style demand before rounding. Size indices reconcile to 100% within each color and destination segment. Purchase and allocation rounding must preserve the approved total or record the variance.

9. Receipt planning, purchasing and open-to-buy

Open-to-buy is the uncommitted portion of the approved receipt plan 0 200 400 600 800 +420 +35 +260 -190 -310 +215 Plannedsales Markdowns Target EOMstock Less BOMstock Less on-order Open-to-buy Illustrative retail value ($000)

Figure 7. Open-to-buy is the uncommitted portion of the approved receipt plan after existing stock and orders.

The MAP defines the receipt need; merchandise purchasing converts that need into supplier commitments. Open-to-buy, or OTB, protects the approved financial envelope while allowing merchants to redirect uncommitted investment as forecasts change.

Calculation Illustrative formula
Planned purchases at retail Planned sales + planned markdowns + target EOM stock - planned BOM stock
Open-to-buy at retail Planned purchases - approved on-order receipts - other committed receipts
Open-to-buy at cost Retail OTB x planned cost complement, or calculate directly at cost
Unit buy need Forward demand + safety / presentation stock - usable inventory position
Executable order Unit need constrained by pack, MOQ, supplier capacity, timing, cash and lifecycle

Table 11. Core receipt and OTB relationships; use consistent valuation and timing.

Commitment strategy

Separate the initial committed buy, optional capacity, chase reserve and exit cancellation window. The plan should show how much investment remains flexible and when that flexibility expires.

10. Scenario planning and constraint management

Scenario planning separates demand opportunity from commitment risk 0 30 60 90 120 Forward retail week Base demand Upside Downside Committed receipt capacity

Figure 8. Scenarios make opportunity and commitment risk visible before purchase decisions are fixed.

Scenario Use Merchandise response
Base Most likely governed forecast Approve core plan and normal service targets
Upside Higher adoption, event response or stronger traffic Reserve chase capacity and prioritize A choices
Downside Slower demand, delay or weaker price response Reduce optional receipts and breadth; protect exit
Supply-constrained Vendor, DC or logistics limits Allocate by served margin, service gap and strategic role
Capacity-constrained Store space or fixture limits Protect core productivity; use hub / digital access for tail

Table 12. Scenarios should identify the decision, not merely display alternate numbers.

Constraint priority

  • Protect safety, legal and contractual requirements.

  • Protect high-value customer service for approved A choices.

  • Preserve presentation and complete-run requirements where economically justified.

  • Use transfers and network availability before incremental buying when feasible.

  • Release or exit low-confidence breadth before cutting productive core depth.

11. Integration with forecasting, purchasing and DC allocation

Stock forecast
demand + timing
Assortment plan
breadth + depth
Purchasing
receipts + OTB
DC allocation
destination
Optimum stock
service + turns

Actual sales, availability, margin, turns and markdowns recalibrate the next plan.

Figure 9. MAP is the coordinating commercial layer across the companion planning and stock processes.

Interface MAP sends MAP receives
Apparel Stock Forecast Approved scope, lifecycle, scenario and hierarchy totals Forward demand, confidence, seasonality and reforecast
Merchandise Purchasing Style-color-size receipt need, window, commitment type and OTB Supplier feasibility, MOQ, packs, due dates, cost and commitment
DC Allocation Range, launch, cluster participation, priority and destination rules Available supply, allocation outcome, shortages and residual stock
Size & Color Management Approved choices, color shares, run policy and participation Size curve, color-size WOS, broken-run and constrained-depth result
Stock Optimization Lifecycle, service segment and assortment role Safety stock, WOS band, transfer and excess recommendations

Table 13. Required information exchange across the merchandise-management series.

Single-version rule

The approved MAP, selected forecast, purchase commitments and allocation run should carry compatible version and effective-date identifiers. Differences must be visible as governed variances, not hidden reconciliations.

12. Worked apparel assortment example

Assume a 26-week women's knitwear plan for three store clusters plus digital. The forecast supports 48 style-color choices. The financial envelope allows an initial commitment plus a chase reserve, while store capacity limits the amount of fashion and extended color placed locally.

Step Illustrative decision Result
1. Financial envelope Planned net sales $420,000; GM target 58%; markdown provision $35,000 Approved category targets
2. Architecture 24 styles, 48 style-color choices across core, seasonal, fashion and test roles Choice-count plan
3. Market range A cluster 100%; B 78%; C 54%; digital 100% of eligible choices Range matrix
4. Depth 5,400 initial units plus 3,000 units reserved for chase Commitment strategy
5. Color / size Color shares and cluster size curves reconcile to each choice total SKU purchase need
6. Purchasing Receipt windows, packs, MOQ and supplier capacity applied Executable orders
7. Allocation Range x store index x color share x size index; subtract local stock SKU-store allocation
8. In-season Reforecast, release chase, transfer excess and shorten winddown runs Closed-loop actions

Table 14. Illustrative MAP decision chain; all values are examples.

Reconciliation checks

  • Choice and SKU demand reconcile to the class / channel financial plan.

  • Store-cluster participation reconciles to capacity and presentation limits.

  • Initial plus chase commitments do not exceed approved receipt and OTB limits.

  • Allocated units do not exceed available-to-allocate supply.

  • Projected stock after exit is explicitly valued as carryover or markdown exposure.

Decision outcome

The MAP approves the customer offer and the investment envelope. Purchasing and allocation may constrain execution, but they must return the variance so merchants can change breadth, depth, timing or service deliberately.

13. Governance, KPIs and review cadence

MAP should be versioned, merchant-owned and transparent. Approved targets, model recommendations, merchant overrides and executed commitments remain separate so the retailer can measure where value was created or lost.

Perspective Measures
Customer / demand In-stock, complete color-size availability, forecast error, served demand and substitution
Assortment Choice count, active style-color count, participation, sales per choice and attribute gaps
Financial Net sales, GM$, GM%, markdown, receipts, OTB, average inventory, turns and GMROI
Lifecycle Sell-through, weeks to peak, chase rate, terminal stock and exit-date adherence
Execution On-time receipts, PO variance, allocation fill, transfer rate and recommendation acceptance
Governance Override frequency, value add, reason, owner, approval and expiry

Table 15. Balanced MAP scorecard.

Illustrative review cadence

Cadence Primary focus Decision
Season / pre-season Financial plan, architecture, range and commitment Approve MAP version
Monthly Class / channel outlook, receipts, stock and OTB Rebalance investment
Weekly in-season Forecast, service, winners, slow choices and capacity Chase, hold, transfer or exit
Post-season Accuracy, sell-through, margin, turns and override value Recalibrate parameters and roles

Table 16. Review decisions at the cadence where they remain actionable.

Governance rule

Every override records the original recommendation, new value, reason, owner, approval status, effective weeks and expected outcome. Post-season review measures whether the override added value.

14. Implementation roadmap and concise rules

Concise MAP rules

Rule Operational meaning
Reconcile top-down and bottom-up Financial targets and detailed choices must agree before approval.
Define choice consistently State whether choice means style, style-color or another customer-visible option.
Plan breadth and depth together Every new choice consumes presentation, size-run and stock investment.
Range before allocating Eligibility, cluster, capacity and lifecycle precede SKU allocation.
Phase receipts to demand Avoid committing stock earlier than lead time and service require.
Keep flexibility visible Separate committed buy, chase reserve, optional capacity and cancellation windows.
Protect the exit Stop replenishment and value terminal stock before the sellable life ends.
Measure business outcome Service, sales, margin, turns, markdown and override value are evaluated together.

Table 18. High-level operating rules for Merchandise Assortment Planning.

Final design principle

The Merchandise Assortment Plan is the retailer's commercial contract between strategy and execution: the right choices, in the right markets, at the right depth and time, within an investment that can achieve the customer, margin and turnover objectives.

RETAIL MERCHANDISE MANAGEMENT PAPER

Apparel Size & Color Management

Size curves, constrained assortments, WOS, ABC policy, store index and size-index allocation

Purpose

A high-level operating design for allocating the right styles, colors and sizes to each store while respecting lifecycle, local demand and shelf-space constraints.

Cybex Retail AI & Analytics Advisory

August 2026 | Illustrative design paper

Executive summary

Apparel inventory should not be managed only at the style or color level. Customer availability is determined at the style-color-size-location level, where a style can appear healthy in total while its highest-demand sizes are already out of stock.

Core principle

Store index controls how much inventory a store should receive. Size index controls the shape of that inventory across XXS-XXL. Color class, lifecycle and capacity determine which portions of the curve are carried.

The recommended operating model separates four decisions:

Illustrative assumptions

All charts and samples in this paper are illustrative. Production parameters should be learned and governed using actual sales, inventory, returns, on-order, promotions, lead times, store capacity, climate, fit and ecommerce data.

1. The normal size curve

A normal size curve is the expected percentage of demand by size for an active style, category or fit family. The curve commonly forms a single peak around the core sizes, but it is not a universal population curve. It varies by customer, fit, brand, garment type, gender category, region, season and channel.

Illustrative normal size curve: XXS to XXL 0 10 20 30 4% 10% 19% 28% 22% 12% 5% XXS XS S M L XL XXL Share of unit demand (%)

Figure 1. Illustrative chain curve: XXS 4%, XS 10%, S 19%, M 28%, L 22%, XL 12%, XXL 5%.

A curve is most useful when it is stable enough to guide decisions but recent enough to reflect changing demand. Use a hierarchical fallback: store-style history where credible, then store-cluster/category, then chain-category or brand-fit history.

Curve quality checks

  • Use net demand, including valid returns treatment, and separate promotional or clearance periods where they distort the normal pattern.

  • Require minimum observations before using a store-specific curve; shrink noisy curves toward the cluster or chain curve.

  • Separate true stockout periods from zero demand. A size cannot sell when it was unavailable.

  • Review fit changes and vendor size relabelling before comparing seasons.

2. Full and shortened size runs

A full run carries every approved size. A shortened run deliberately limits size breadth because the product is winding down, the store has limited presentation space, or local demand does not justify every tail size. The rule should be based on demand coverage and network availability, not a fixed assumption that every small store needs the same sizes.

Carried size run narrows as the style winds down
XXSXSSMLXLXXL
Full run carried carried carried carried carried carried carried
Limited shelf carried carried carried carried carried
Early winddown carried carried carried
Late winddown carried carried

Figure 2. Example run widths. Actual carried sizes should shift according to the store size index.

Status Illustrative run Inventory objective Replenishment rule
Active / full XXS-XXL Protect service and complete size runs Replenish to target WOS by size
Limited shelf XS-XL default Cover the greatest local demand with fewer slots Prioritize A colors and A/B sizes
Winddown - early S-XL example Reduce depth and stop new exposure Network transfers only; lower target WOS
Winddown - late S-L example Consolidate sellable units and exit cleanly No routine replenishment; exception only

Table 1. Illustrative lifecycle and space policies; category-specific governance is required.

Winddown logic

Winddown is a reduction in future commitment, not an instruction to strand random units. Reduce target WOS, stop or restrict purchase orders, transfer fragmented tail inventory toward stores or channels where it can still sell, and preserve the sizes needed to complete the most productive remaining runs.

Limited-shelf logic

For a space-constrained store, select the minimum set of sizes that covers a chosen percentage of normalized local demand. A default XS-XL run may be appropriate for one store, while another store may shift to S-XXL. Excluded sizes should remain discoverable and fulfilable through ecommerce or the store network whenever possible.

3. Weeks of supply by size

Weeks of supply (WOS) must be calculated for every size, not only for the total style. Total style WOS can look balanced while core sizes are near stockout and tail sizes are overstocked.

Formula

WOS(size) = available inventory(size) / expected weekly unit demand(size). Available inventory should follow a governed definition, such as on hand plus eligible inbound minus reservations or committed demand.

Weeks of supply by size reveals hidden imbalance 0 2 4 6 8 4.0 4.0 3.5 3.0 4.0 5.0 7.0 XXS XS S M L XL XXL Illustrative target band: 3.5-4.5 WOS

Figure 3. Overall style WOS is 3.9 weeks, but M is at 3.0 while XXL is at 7.0.

Metric XXS XS S M L XL XXL
Weekly demand 2 5 10 14 11 6 2
Available stock 8 20 35 42 44 30 14
WOS 4.0 4.0 3.5 3.0 4.0 5.0 7.0

Table 2. Sample WOS calculation across the entire size curve.

Interpretation rules

  • Low WOS in an A size is a lost-sales risk and should rank ahead of excess tail inventory.

  • High WOS in a C size may require a transfer, reduced replenishment, digital fulfilment or markdown action.

  • When demand is very low, WOS becomes unstable. Apply minimum-demand rules and also track units, age and last-sale date.

  • Use separate WOS targets by lifecycle, class, vendor lead time and service objective.

4. Color, size and ABC classification

ABC classification converts limited capacity into an explicit priority order. A style, color and size can each have a class. The final color-size priority should reflect all three rather than using style rank alone.

Level A B C Suggested use
Style Highest productivity Middle productivity Tail / test / exit Controls store penetration and total depth
Color Largest cumulative color demand Secondary demand Long-tail fashion color Controls color count and curve width
Size Core local demand Secondary local demand Tail local demand Controls size inclusion and depth

Table 3. ABC may use the retailer's preferred 85/10/5 convention or a category-specific alternative.

Illustrative color classification

For a style with color sales mix of Black 48%, Navy 32%, Stone 12% and Sage 8%, Black and Navy form the A-color group, Stone is B and Sage is C. A limited-space store should normally protect Black and Navy before adding Stone; Sage may be limited to selected stores or ecommerce.

Sample 22-unit allocation for a space-constrained store
XXSXSSMLXLXXL
Black - A 11 23 21 1
Navy - A 01 13 21 0
Stone - B 00 11 10 0
Sage - C 00 00 00 0

Cell value = opening or target units; excluded colors remain available through the network when possible.

Figure 4. Sample capacity-constrained allocation: two A colors, one B color and no C-color presentation.

Priority policy for limited space

Color / size A size B size C size
A color First priority; maintain depth Carry where demand supports Carry tail only if local index supports
B color Carry core sizes Selective Usually network / ecommerce
C color Top stores or test only Rare Do not allocate routinely

Table 4. Illustrative color-size service hierarchy for a capacity-constrained store.

5. Store index and size index

Store index and size index solve different problems and should not be combined into one unexplained factor.

Store index = total depth

A store index measures the store's demand intensity relative to comparable stores for a department, class, category or style group. An index of 1.30 suggests approximately 30% more total demand than the comparison-store baseline; 0.70 suggests approximately 30% less.

Size index = curve shape

A size index measures the store's size mix relative to the chain or cluster size mix. An XL index of 1.25 means XL has 25% greater share at that store than in the baseline curve. It does not by itself mean the store needs 25% more total inventory.

Definitions

Store index(store, class) = store weekly class demand / average weekly class demand for comparable stores.

Size index(store, size, class) = store size-mix percentage / chain-or-cluster size-mix percentage.

Adjusted size weight(size) = baseline curve(size) x size index(store, size).

Normalized store curve(size) = adjusted size weight(size) / sum of adjusted weights for all eligible sizes.

Size index changes the shape of the store curve 0 10 20 30 XXS XS S M L XL XXL Normalized size demand (%) Chain curve Store A: smaller-size skew Store B: larger-size skew

Figure 5. The size index reshapes the curve while normalization keeps the selected curve equal to 100%.

Illustrative store comparison

Store Store index Size pattern Allocation effect
101 - high volume 1.35 Near chain curve More total units; full curve on A colors
205 - compact 0.72 Smaller-size skew Fewer units; prioritize XXS-L where justified
318 - regional 0.95 Larger-size skew Moderate depth; shift curve toward L-XXL

Table 5. Store index changes quantity; size index changes the distribution of that quantity.

6. High-level allocation and distribution algorithm

1  Demand
forecast
2  Store
index
3  Color +
size index
4  Target WOS
+ lifecycle
5  Net need
6  Capacity +
ABC constraints
7  Rank +
optimize
8  Approve +
measure

Every recommendation should retain its inputs, rule version, reason code and approval outcome.

Figure 6. Recommended decision loop for initial allocation, replenishment and redistribution.

Demand calculation

1. Forecast store-style-color demand using the average-store forecast, store index, local style affinity, normalized color mix, seasonality, promotion and channel effects.

2. Split store-style-color demand into sizes using the normalized store size curve.

3. Convert forecast to target stock using the target WOS appropriate to class, lifecycle, lead time and service objective.

4. Calculate net need after subtracting usable on-hand and inbound supply and adding reservations or committed demand where applicable.

Illustrative net-need formula

Net need = MAX(0, target WOS x weekly SKU forecast - usable on hand - eligible inbound + committed demand). The final quantity is then constrained by pack sizes, presentation minimums, capacity, lifecycle and available network supply.

Constraint and ranking logic

  • Establish style and color assortment eligibility before assigning depth.

  • Protect A-style / A-color / A-size combinations first in limited capacity.

  • Rank needs using expected lost margin, stockout probability, service importance and confidence.

  • Prevent allocations that create stranded tail sizes or break stronger runs elsewhere.

  • Use a minimum presentation rule only while the style remains active; reduce or remove it in winddown.

  • Return reason codes such as CORE_SIZE_STOCKOUT, COLOR_C_CAPACITY_BLOCK or WINDDOWN_TRANSFER_ONLY.

7. Worked allocation example

Assume an A-class active style, 22 available presentation units, four eligible colors and the chain curve shown earlier. The store index determines overall demand; store size indices reshape the curve; color ABC and shelf capacity then establish the priority order.

Step Input Black A Navy A Stone B Sage C Decision
1 Color mix 48% 32% 12% 8% Classify A/A/B/C
2 Size eligibility Full Core + tails by index Core only Network only Choose curve width
3 Capacity request 11 8 3 0 22 units total
4 Lifecycle Active Active Active Active Normal WOS for eligible SKUs
5 Execution Allocate Allocate Allocate selectively Do not present Retain ecommerce availability

Table 6. Example decision sequence for the 22-unit color-size matrix.

What the algorithm should explain

A merchant should be able to select any recommended unit and see why it was allocated: forecast, store index, size index, color class, WOS gap, capacity effect, alternative source and expected result. Explainability turns the model into a controlled retail workflow rather than a black-box optimization.

Transfer example

SKU From From WOS To To WOS Reason
Black / M Store 101 1.6 Store 205 8.1 A size; high lost-sales risk
Navy / XL Store 318 1.9 Store 101 6.4 Local larger-size index
Stone / S Ecommerce hub 2.2 Store 318 9.0 B color; consolidate winddown demand

Table 7. Illustrative transfer recommendations; apply transfer cost, handling and sell-through thresholds.

8. Governance and implementation

The most effective size and color system combines statistical demand with explicit retail policy. Merchants should control thresholds and exceptions, while the system applies them consistently and records results.

Required governed parameters

Parameter Examples Owner
Curve hierarchy Store-style, cluster-category, chain-category Merchandise planning
ABC thresholds 85/10/5 or category-specific bands Merchandising + finance
Target WOS By class, lifecycle, lead time and season Planning + purchasing
Capacity Style/color/size slots or total units Store operations
Lifecycle rules Launch, active, winddown, exit Merchandising
Transfer economics Minimum benefit, cost, distance, days remaining Operations + finance
Approval rights Auto-approve, merchant review, executive exception Governance owner

Table 8. Parameter ownership prevents hidden model changes and conflicting rules.

Key performance measures

Service Inventory Decision process
Core-size in-stock rate WOS by size and color Recommendation acceptance
Complete size-run rate Aged units and inventory turns Merchant time saved
Stockout duration Full-price sell-through Override reason and outcome
Lost-sales estimate GMROI and markdown exposure Forecast and index accuracy

Table 9. Balanced scorecard for service, inventory productivity and adoption.

Final design principle

Allocate the fewest units that can deliver the required service level, in the colors and sizes the local customer is most likely to buy, while preserving network access to the broader assortment.

Appendix: concise policy rules

Rule Operational meaning
Normal curve Maintain all eligible sizes; depth follows size-level WOS.
Limited shelf Carry the smallest set of sizes and colors that reaches the local demand-coverage target.
Winddown Lower target WOS, stop new exposure, and consolidate sellable units.
A colors Protect first; usually receive the broadest size run.
B colors Core sizes and selective stores.
C colors Test, top-store or ecommerce/network availability.
Store index Scales total store demand and inventory depth.
Size index Reshapes the store curve, then is normalized.
WOS Calculate at style-color-size-location; do not rely only on style totals.
Human control High-impact actions require transparent reasons and approval.

Table 10. High-level policy summary.

APPAREL MERCHANDISE MANAGEMENT PAPER

Apparel Stock Forecast

Data warehouse, normalized demand, seasonality, lead time, safety stock, in-stock service and forward-week inventory

Purpose

A high-level forecasting design that converts governed retail data into demand, stock and receipt projections used consistently by Merchandise Assortment Planning, Merchandise Purchasing and DC Allocation.

Cybex Retail AI & Analytics Advisory

August 2026 | Illustrative design paper

Executive summary

An apparel stock forecast is more than a sales projection. It is a forward-week view of demand, receipts, inventory position, safety stock, availability and exit risk at the level required to make merchandise decisions. The forecast should be built once on governed data and then consumed consistently by assortment planning, purchasing and DC allocation.

Core principle

Forecast unconstrained customer demand first. Then convert demand into a stock requirement using lead time, review cycle, target in-stock service, safety stock, WOS limits, presentation rules, packs, capacity and lifecycle.

Three coordinated outputs

  • Demand forecast: expected unconstrained unit demand by forward retail week.

  • Stock forecast: projected beginning stock, receipts, demand, transfers, markdowns and ending stock.

  • Decision requirement: the units, timing and location needed to achieve the governed service and inventory objective.

Downstream use

Consumer Forecast decision Required level
Merchandise Assortment Plan Breadth, depth, lifecycle, color and size investment Department -> class -> style / choice
Merchandise Purchasing Buy quantity, receipt timing, open-to-buy and supplier commitments Style-color-size by receipt week
DC Allocation Destination, quantity, release timing and replenishment priority SKU-store by ship / arrival week

Table 1. One forecast foundation, expressed at the grain required by each decision.

All numerical examples and policy values in this paper are illustrative. Production parameters should be calibrated through backtesting, service economics and merchant governance.

1. Forecasting operating model

Source data
  • POS sales
  • Inventory snapshots
  • PO / receipts
  • Product & store
  • Price / promo
Data warehouse
  • Retail calendar
  • Conformed keys
  • Quality rules
  • Stockout flags
  • History normalization
Forecast engine
  • Baseline demand
  • Seasonal indices
  • Forecast alternatives
  • Safety stock
  • Forward inventory
Decisions
  • Assortment plan
  • Purchasing
  • DC allocation
  • Replenishment
  • Merchant review

Figure 1. A governed data warehouse creates a single forecast foundation for the assortment plan, purchasing and DC allocation.

Design requirements

  • Use a common retail calendar, product hierarchy, location hierarchy and currency / unit basis.

  • Retain raw observations, normalized observations, overrides, parameters and selected forecast versions.

  • Separate demand forecasting from supply feasibility so constrained sales do not define future demand.

  • Publish weekly forecasts at reconciled levels: class, style, color, size, DC, store cluster and store.

  • Attach reason codes, confidence and model version to every merchant-facing recommendation.

2. Data warehouse foundation

The data warehouse should preserve atomic retail events and publish conformed weekly facts. The forecast engine can then rebuild any history, explain adjustments and reconcile plans without relying on spreadsheets as the system of record.

Domain Minimum facts Forecast use
Sales / returns Transaction date, SKU, store, units, value, discount, return Demand history, price response, returns normalization
Inventory Daily / weekly on hand, available, reserved, in transit, on order In-stock censoring, stock position, WOS and receipt need
Purchasing PO line, supplier, order date, due date, receipt date, cancellations Actual lead time, reliability and future receipts
Product Style, color, size, season, class, cost, ticket, lifecycle Hierarchy, analogs, margin and eligibility
Location Store / DC, cluster, capacity, climate, opening / closure Store indexing, ranging and allocation
Calendar / events Retail week, holidays, campaigns, weather / local events if governed Seasonal alignment and causal adjustments

Table 2. Core warehouse domains for an apparel stock forecast.

Data-quality gates

  • Complete product and location keys

  • No negative usable inventory without an explained adjustment

  • PO dates and quantities reconcile to receipts

  • Ranged / not-ranged status is explicit

  • Promotions and markdown periods are identifiable

  • History snapshots are immutable and versioned

3. Normalized and de-seasonalized sales history

Normalization and de-seasonalization expose the true baseline 0 30 60 90 stockout Retail week Observed sales Normalized demand De-seasonalized baseline

Figure 2. Illustrative history: normalization removes known distortions; de-seasonalization reveals the underlying baseline.

Normalization sequence

Step Treatment Control
1. Validate Remove duplicate / corrupt events; reconcile returns and transfers Never silently delete demand
2. Availability Flag stockout, broken size run and low in-stock periods Do not interpret zero sales as zero demand
3. Event effects Identify promotion, markdown, store closure, bulk sale and launch Retain event factor and original sales
4. Impute demand Estimate lost demand only where evidence supports censoring Cap and confidence-score the correction
5. Normalize Restate to a comparable price, store-week and lifecycle basis Preserve both raw and normalized history
6. De-seasonalize Divide normalized demand by the governed seasonal index Rebase indices to average 1.00

Table 3. An auditable preparation sequence for sales history.

Key warning

Sales are observed demand only when the item was available, ranged and discoverable. Apparel styles with missing core sizes may be demand-constrained even when total style stock is positive.

4. Seasonality and apparel lifecycle

Seasonality describes the repeatable timing pattern around the baseline. It may be estimated at department, class, attribute, climate cluster or style-family level depending on history depth. A new fashion style normally inherits an analog or pooled seasonal profile until its own evidence is credible.

Component Definition Apparel treatment
Baseline Underlying level after normalization and de-seasonalization Trend-cap to avoid runaway extrapolation
Seasonal index Relative demand by retail week; average normally equals 1.00 Use class / climate / attribute hierarchy
Lifecycle curve Launch, build, peak, decay and exit shape Override annual seasonality for short-life fashion
Event factor Incremental effect of holiday, campaign, promotion or weather Keep separate from baseline when possible
Re-seasonalized forecast Baseline x seasonal index x approved event factor Reconcile to plan totals and lifecycle units

Table 4. Demand components should remain visible rather than being buried in one number.

Core equations

De-seasonalized baseline = normalized demand / seasonal index.

Re-seasonalized forecast = projected baseline x seasonal index x approved event factor.

For a short-life style, use a lifecycle curve whose weekly proportions sum to 100% of the style demand plan, then distribute by color, size and location indices.

Hierarchy rule

Estimate seasonality at the lowest level with stable evidence, but fall back to a pooled parent or attribute group when observations are sparse. Reconcile child forecasts to the approved parent total.

5. Lead time, protection period and forward weeks

Lead time determines when a forecast can still influence stock Review +release Supplier / productionlead time Transit,put-away Selling coverageafter receipt Later forecast horizonfor MAP / OTB 0 4 8 12 16 20 24 26 Protection period Forward weeks retained for decisions

Figure 3. The forecast horizon must extend beyond the protection period and the decision lead time.

Definitions

Term Meaning Forecast implication
Supplier lead time Order release to supplier-ready or ship date Determines the last week a purchase can change supply
Logistics lead time Ship through receiving and put-away Include actual distribution delay, not only vendor promise
Review period Time until the next replenishment / buying decision Adds exposure between decisions
Protection period Lead time + review period Forecast and uncertainty window covered by reorder point
Forward weeks Future retail weeks retained in the forecast version 13, 26 or 52 weeks depending on decision horizon

Table 5. Time parameters connect the forecast to executable decisions.

Apparel controls

  • Use realized lead-time distributions by supplier and route, not only contracted averages.

  • Freeze or taper forecasts beyond the exit week; safety stock must not create stock after the sellable life.

  • Align order cut-offs, DC release dates and store arrival weeks to the retail calendar.

  • Retain forward forecasts even where supply is unavailable so lost opportunity remains visible.

6. Safety stock and target in-stock level

Higher in-stock targets require disproportionately more safety stock 17 22 27 32 37 Illustrative policy point: 97.5% / 31.4 units 90 92 94 96 98 Cycle service target (%) Safety stock units

Figure 4. Illustrative relationship: the final points of in-stock service require increasing inventory protection.

Safety-stock logic

For weekly independent forecast errors and stable lead time, an operational approximation is: Safety stock = z x weekly forecast-error standard deviation x square root of protection weeks. When lead time also varies, combine demand and lead-time variance or simulate the distribution. Backtest against realized service and excess.

Policy segment Illustrative cycle service z factor Apparel note
A product / A store 98.0% 2.05 Protect core and proven fashion
A / B or B / A 97.0% 1.88 High service with capacity control
B / B 95.0% 1.65 Balanced default
C / C 90.0% 1.28 Limited depth or network fulfilment
Winddown Economic / exit rule N/A Do not replenish solely to restore a size run

Table 6. Illustrative service policy; calibrate by margin, substitution, lifecycle and space.

In-stock measurement

Measure availability only while an item is ranged and sellable. Report SKU in-stock, complete color-size run, demand-weighted in-stock and stockout duration. A style can appear in stock while the highest-demand size or color is unavailable.

7. Parameter-driven stock forecast alternatives

Merchants should compare forecast alternatives before selection 0 30 60 90 Forward retail week Moving average Exponential smoothing Seasonal naive Regression + drivers Judgement override

Figure 5. Different methods may be appropriate by lifecycle and data sufficiency; merchants can compare the alternatives before selection.

Alternative Best fit Key parameters
Moving average / EWMA Stable replenishment with adequate own history History window, decay, outlier handling
Trend + seasonal Carryover / basic apparel Trend window, cap / floor, seasonal hierarchy
Lifecycle curve Short-life fashion and launch Total demand, launch week, peak, decay, exit
Analog / attribute New style with limited history Analog set, similarity weights, price and store factors
Merchant plan Strategic buy, event or new concept Plan version, override horizon, owner and reason
Hybrid ensemble Mixed evidence and operational scale Method weights, error window, confidence threshold

Table 7. Forecast alternatives should be parameter-controlled and backtested.

Separation of concerns

The selected demand forecast estimates what customers would buy. The stock forecast applies receipts, safety stock, WOS, packs, capacity, lifecycle and available supply to show what inventory is required and feasible.

8. Forecast parameter system and selection

A parameter-driven design permits different forecasting behaviour without rebuilding the application. Parameters should be effective-dated, versioned, inherited through hierarchy and overrideable only by authorized roles.

Parameter family Examples Decision effect
History Weeks used, stockout correction, return treatment, promo normalization Defines the comparable demand signal
Method Moving average, EWMA, trend-seasonal, lifecycle, analog, ensemble Creates alternative demand paths
Hierarchy Class, attribute, climate cluster, style, color, size, store Controls pooling, inheritance and reconciliation
Time Forward weeks, lead time, review cycle, freeze window, exit week Defines executable horizon
Service / stock In-stock target, z factor, min / target / max WOS, presentation Converts demand into stock requirement
Execution Pack, MOQ, capacity, DC availability, transfer eligibility Converts requirement into a feasible action
Governance Override limits, owner, reason code, expiry, approval Controls human judgment and auditability

Table 8. A practical parameter dictionary for apparel stock forecasting.

Selection and reconciliation

  • Backtest eligible methods on rolling historical cut-offs using the same data that would have been available then.

  • Select by WAPE, bias, service outcome and stability - not error alone.

  • Use a confidence score to determine whether style-level history or a pooled analog should dominate.

  • Reconcile style-color-size-store forecasts to approved class and channel plans without erasing local demand shape.

  • Store the unadjusted model result, merchant override and final consensus forecast separately.

9. Forecast use in Merchandise Assortment Planning

Forecast
by forward week
Assortment
breadth + depth
Purchase
receipts + OTB
DC allocation
store / size
Sales, stock
& service

Closed-loop learning: realized sales, stock and service feed back into the next forecast.

Figure 6. The forecast must reconcile across downstream decisions and learn from actual sales, stock and service.

The Merchandise Assortment Plan converts demand opportunity into planned breadth, depth, timing and option productivity. It should receive a baseline demand forecast plus scenario parameters, not only a single seasonal total.

MAP decision Forecast input Planning output
Class / subclass opportunity Forward demand, trend, seasonality, margin and service Sales, receipt, stock and markdown targets
Choice count / breadth Demand concentration and forecast confidence Number of styles and colors by store cluster
Depth Weekly demand, size curve, color share and lead time Initial and replenishment units per choice
Lifecycle timing Launch, peak, decay and exit forecast Floor dates, receipt windows and exit dates
Scenario Base, upside, downside and event alternatives Investment and open-to-buy options

Table 9. The forecast supports both financial and assortment structure decisions.

MAP rule

Assortment breadth consumes presentation and safety-stock investment. Add choices only when incremental demand and margin exceed the service, space and fragmentation cost of carrying another style-color-size run.

10. Forecast use in Merchandise Purchasing

Purchasing converts the forecast into time-phased receipts and supplier commitments. It must consider inventory position, forecast through the protection period, safety stock, planned markdowns, existing open orders, MOQ, packs, lead time and the remaining sellable weeks.

Line Illustrative calculation Units
Forecast demand: weeks 1-10 Weekly re-seasonalized forecast summed 820
Safety stock at first receipt 97% service; forecast-error model 72
Presentation / launch minimum Required color-size display depth 48
Gross stock requirement MAX(demand + safety stock, presentation) 892
Less usable on hand Available and eligible for sale -210
Less eligible on order Confirmed to arrive inside need window -300
Net purchase need Before pack, MOQ and budget 382
Executable order Rounded to 12-unit pack 384

Table 10. Illustrative purchase-need calculation. Avoid double-counting presentation stock if it is already embedded in the target.

Purchase alternatives

  • Base buy: selected forecast and normal service policy.

  • Upside reservation: optional or delayed commitment for high-uncertainty demand.

  • Chase buy: shorter lead-time replenishment after early sales evidence.

  • Exit protection: cap receipts so inventory can sell through by the governed exit date.

Open-to-buy connection

The forecast should translate unit need into retail value, cost and margin by receipt week. Purchasing approves only the feasible portion within supplier, cash, capacity and open-to-buy constraints.

11. Forecast use in DC Allocation

Illustrative DC allocation need after store and size indexing
XXSXSSMLXLXXL
A store 02 57 52 0
B store 14 912 94 1
C store 03 710 83 0
Digital / hub 01 35 42 0

Figure 7. DC allocation need reflects forecast demand, current inventory, safety stock, store index and size index.

DC allocation distributes constrained supply to the SKU-location combinations where it protects the most expected demand and margin. The process should calculate need first, then optimize against available DC stock, packs, store capacity and shipment rules.

Factor Application in allocation
Store index Scales chain or cluster demand to the location based on normalized productivity and eligibility.
Size index Distributes style or color demand across sizes based on local / cluster demand shape.
Color share Limits breadth and depth to proven or strategic colors.
In-stock target Sets differential protection by product ABC, store ABC and lifecycle.
Inventory position Subtracts usable on hand and eligible inbound before ranking need.
Forward weeks Uses demand through arrival and review, not only last-week sales.

Table 11. Forecast elements used in initial and replenishment allocation.

Illustrative need: SKU-store forecast = style forecast x store index x color share x size index. Net allocation need = target stock through the protection period + safety stock - inventory position, then constrained and pack-rounded.

12. Worked apparel forecast example

Assume a carryover knit style with enough history for a trend-seasonal forecast. The selected 10-week unconstrained demand is 820 units. The first effective receipt arrives after a six-week lead time and one-week review period. Forecast error over the seven-week protection period supports 72 units of safety stock at the selected service target.

Decision stage Forecast transformation Illustrative result
Demand preparation Raw sales corrected for stockouts and promotion; de-seasonalized Weekly baseline
Forecast selection Trend-seasonal beats eligible alternatives in backtest 820 units / 10 weeks
MAP Forecast distributed to 4 colors and 7 sizes; breadth constrained by store tier Approved option plan
Purchasing Demand + safety stock - inventory position; pack-rounded 384-unit order
DC allocation Store index x color share x size index; subtract local stock SKU-store need matrix
Reforecast Early sales update baseline and confidence; receipt / exit dates retained Chase, hold or cancel decision

Table 12. One forecast version, transformed for three downstream decisions.

Control totals

  • Color shares sum to 100% of the style forecast before rounding.

  • Size indices sum to 100% within each style-color and destination segment.

  • Store indices reconcile store demand to the approved channel / cluster total.

  • Allocated units cannot exceed available-to-allocate DC inventory.

  • Beginning stock + receipts + transfers in - demand - transfers out - adjustments = ending stock.

  • Projected ending stock after the exit week is treated as markdown / transfer exposure.

13. Backtesting, KPIs and governance

Backtesting compares accuracy and bias, not accuracy alone 0 10 20 30 40 31 26 34 22 29 Movingaverage Exponentialsmoothing Seasonalnaive Regression+ drivers Judgementoverride +12 0 -12 -4 -1 +6 +2 +9 WAPE (%) - lower is better Bias (%) - zero is neutral

Figure 8. Backtesting should compare accuracy and bias by horizon, lifecycle, class and forecastability segment.

Measure Purpose Recommended cut
WAPE / MAE Forecast magnitude of error 1, 4, 8, 13 and lead-time horizons
Bias Systematic over- or under-forecast Method, merchant, class and lifecycle
In-stock / fill rate Customer service delivered Product ABC x store ABC x size
Turns / average WOS Inventory productivity Class, lifecycle, channel and location
Markdown / terminal stock Exit quality Season, style and color
Override value add Whether human changes improve the outcome Reason code and approver
Forecast stability Change between forecast versions Freeze window and horizon

Table 13. Forecast accuracy is necessary, but operational and financial outcomes complete the scorecard.

Governance rules

  • Every parameter and forecast version has an owner, effective date and approval status.

  • Overrides record original value, new value, reason, owner, expiry and expected outcome.

  • Methods are promoted only after rolling-origin backtests and controlled pilot results.

  • Actual service and excess recalibrate safety-stock and in-stock policies.

14. Implementation roadmap and concise rules

Concise forecasting rules

Rule Operational meaning
Forecast demand, not constrained sales Correct stockout and broken-size censoring before projecting demand.
Keep raw and adjusted history Every normalization and override remains auditable.
De-seasonalize before trend Estimate the baseline separately, then apply seasonality and events.
Forecast far enough forward Horizon must exceed lead time, review period and decision window.
Differentiate service Target in-stock and safety stock vary by value, store and lifecycle.
Separate need from feasibility Calculate unconstrained requirement before supply, pack, capacity and budget limits.
Reconcile every level Style, color, size and store forecasts tie to the approved merchandise plan.
Measure business outcome Accuracy, bias, service, turns and markdowns are evaluated together.

Table 15. High-level operating rules for Apparel Stock Forecast.

Final design principle

A strong apparel stock forecast creates one trusted forward view of demand and inventory, while preserving the different decisions made by assortment planners, buyers and DC allocators. The system should be parameter-driven, explainable and continuously recalibrated.

RETAIL MERCHANDISE MANAGEMENT PAPER

Retail Stock Optimization & Optimum Stock

Safety stock, service levels, WOS policy, ABC priorities, investment efficiency and inventory turns

Purpose

A high-level operating design for maximizing in-stock service with the least practical inventory investment while improving stock turnover and controlling excess.

Cybex Retail AI & Analytics Advisory

August 2026 | Illustrative design paper

Executive summary

Stock optimization is not the pursuit of the highest possible inventory level. It is the disciplined selection of the lowest practical inventory position that can deliver the required customer service, presentation, replenishment and financial outcomes for each SKU-location.

Core principle

Optimum stock balances the expected cost of stockouts against the cost of holding, transferring and marking down inventory. Product importance, store importance, lifecycle, lead time and demand variability determine where investment should be protected.

The operating model separates six decisions:

Illustrative assumptions

All charts, service levels, WOS bands and examples are illustrative. Production policies should be calibrated from actual demand, lost-sales estimates, margins, lead times, review cycles, pack sizes, capacity, lifecycle, forecast error and transfer economics.

1. The concept of optimum stock

Optimum stock is the policy-driven inventory position at which the next unit of stock is no longer expected to create enough service or margin benefit to justify its holding, transfer, space and markdown risk. It is a range, not a permanently fixed number, because forecasts, lead times and lifecycle conditions change.

Working definition

Optimum stock = the smallest feasible inventory position that meets the selected service target and presentation requirement, within maximum WOS, capacity, lifecycle and investment constraints.

Optimum stock balances service, investment and turnover 82 87 92 97 Illustrative optimum: 97.5% service / 5.0 turns 60 80 100 120 140 Stock investment index (100 = illustrative optimum) In-stock service (%) Annual inventory turns

Figure 1. Service gains diminish as investment rises; the economic optimum occurs before the theoretical maximum in-stock rate.

Interpretation

  • Understocking produces avoidable stockouts, lost margin and incomplete assortments.

  • Overstocking can add very little service while reducing turns and increasing markdown exposure.

  • The optimum varies by product ABC, store ABC, lifecycle, lead time, substitutability and margin.

  • The objective is not one chain-wide WOS number; it is a governed SKU-location policy.

2. Service levels and safety stock

An in-stock target expresses the probability or percentage of customer demand the retailer intends to satisfy from available inventory. Cycle service level and unit fill rate are related but different measures; the policy should name which one it governs. A higher service target requires disproportionately more safety stock as the target approaches 100%.

Safety stock formula - demand uncertainty

When lead time is stable: Safety stock = z x standard deviation of demand during the protection period. When both demand and lead time vary, use a combined variance model and validate the result against observed stockout behaviour.

Illustrative cycle service z factor Typical policy use
90% 1.28 Long-tail or highly substitutable demand
95% 1.65 Balanced service segment
97.5% 1.96 Important product-store combinations
99% 2.33 Exceptional high-service combinations

Table 1. Standard normal service factors; use only when the statistical assumptions are appropriate.

Protection period

Protection period normally includes supplier or transfer lead time plus the replenishment review period. Forecast demand over that period establishes the base requirement; safety stock protects the uncertainty around it. Presentation minimums and pack constraints may raise the executable quantity.

Min-target-max policy controls replenishment and excess Order up to target when the position hits the trigger; maximum is a ceiling, not a buy-to level Excess Healthy Lead-time dip Starvation 0 2 4 6 8 order placed receipt lands, up to target 0 2 4 6 8 10 12 Week Inventory position Maximum (ceiling) Target (order up to) Minimum (trigger) Safety floor

Figure 2. A min-target-max policy triggers replenishment before the safety floor and prevents routine buying above the maximum.

Inventory-position formulas

Inventory position = usable on hand + eligible on order + confirmed inbound - reservations - backorders.

Reorder point = forecast demand during the protection period + safety stock.

Net need = MAX(0, target inventory position - current inventory position), then adjusted for packs, minimum presentation, capacity and lifecycle.

3. Minimum, target and maximum WOS

WOS turns the stock policy into an understandable operating band. Minimum WOS is the replenishment trigger or starvation threshold. Target WOS is the desired post-action position. Maximum WOS limits excess investment and identifies transfer or markdown candidates. Each threshold should vary by product class, store class, lifecycle and lead time.

Illustrative active-product WOS bands by ABC class 0 3 6 9 12 3.0 4.5 6.0 4.0 6.0 8.5 5.0 8.0 12.0 A products B products C products Weeks of supply Minimum WOS Target WOS Maximum WOS

Figure 3. Illustrative active-product WOS bands; long-lead categories may require materially higher coverage.

Product class Minimum WOS Target WOS Maximum WOS Primary response
A 3 5 8 Protect service; replenish first
B 2 4 7 Balance service and investment
C 1 3 5 Limit depth; use network availability

Table 2. Illustrative active-lifecycle WOS policy. Launch and winddown require separate bands.

4. ABC classification for stock and stores

Product ABC and store ABC solve different allocation questions. Product ABC ranks the economic or service importance of the item. Store ABC ranks the demand productivity, strategic role and capacity of the location. The two classifications form a service and investment matrix.

Product ABC

A practical product ranking may use cumulative annualized gross margin, net sales or demand contribution. Cybex can support the retailer's 85/10/5 convention: A items produce the first 85% of the selected contribution, B the next 10% and C the final 5%. Lifecycle and strategic items may require governed overrides.

Store ABC

Store classification should consider sales volume, category productivity, local demand confidence, strategic presentation role, fulfilment capability and space. A high-volume A store is not automatically entitled to every C product; capacity and local relevance still apply.

Illustrative target in-stock service matrix
A storeB storeC store
A product 98.5% 97.5% 96.5%
B product 97.0% 96.0% 94.5%
C product 95.0% 93.0% 90.0%

Figure 4. Product-store service matrix: highest protection is reserved for combinations with the greatest service and financial value.

Combination Service posture Stock posture Network posture
A product / A store Highest governed target Fullest justified depth Local availability protected
A product / C store High but capacity-aware Core depth only Rapid transfer or hub backup
C product / A store Selective or test Presentation minimum Replenish only on evidence
C product / C store Lowest routine target Normally excluded Ecommerce / network access

Table 3. Illustrative product-store policy combinations.

5. Optimizing in-stock percentage and stock investment

The optimization objective should maximize expected full-price demand served and margin protected, subject to an inventory budget, store capacity, availability, pack sizes and lifecycle. It should not maximize service independently of cost, because the last fractions of service can require disproportionate inventory.

Optimum stock minimizes the combined cost of shortage and excess 0 10 20 30 40 50 Minimum total cost 60 70 80 90 100110 120130 140 Stock investment index Expected lost-margin cost Holding / markdown cost Total relevant cost

Figure 5. Optimum stock occurs near the minimum of expected shortage cost plus holding and markdown cost.

Optimization objective

Maximize expected served margin and service, less holding, transfer and markdown cost, subject to inventory investment, capacity, pack, lifecycle and network constraints.

6. High-level stock optimization algorithm

1  Forecast
& variability
2  Product +
store ABC
3  Service
target
4  Safety stock
& protection
5  Min / target /
max WOS
6  Capacity +
pack constraints
7  Optimize +
rank actions
8  Approve +
measure

Figure 6. Closed-loop optimization for initial allocation, replenishment, transfer and exit decisions.

Decision order

  • Forecast SKU-location demand and demand variability over the protection period.

  • Apply product ABC, store ABC, lifecycle and strategic eligibility.

  • Set the service target and calculate safety stock.

  • Calculate minimum, target and maximum WOS and the resulting net need.

  • Apply presentation, pack, capacity, open-order and available-supply constraints.

  • Rank replenishment, transfer, retain, markdown and exit actions by expected economic benefit.

  • Require approval for governed exceptions and write accepted actions to execution workflows.

  • Measure in-stock, turns, forecast error, markdowns and realized outcome; recalibrate.

7. Cybex Store Stock Planner operating model

The Store Stock Planner provides a practical merchant interface for the policy. The WOS slider defines starvation, healthy and surplus bands; capacity identifies required exits; the style grid ranks service gaps; and color-size detail prevents a healthy style total from hiding broken selling combinations.

Cybex Store Stock Planner showing WOS policy, floor capacity, transfer candidates, starved styles, markdown candidates and color-size availability.

Figure 7. Cybex Store Stock Planner example supplied by the user; values shown are application data, not policy recommendations in this paper.

Planner element Optimization role Recommended enhancement
WOS policy slider Defines minimum and maximum operating band Allow bands by product ABC, store ABC and lifecycle
Styles on floor / capacity Measures assortment pressure Separate style slots, SKU slots and unit capacity
Starved styles Identifies service risk Rank by lost margin, ABC and forecast confidence
Transfer candidates Releases excess investment Include receiving-store benefit and transfer cost
Markdown candidates Flags persistent surplus Use age, lifecycle and projected sell-through
Color / size tiles Exposes broken availability Show safety floor, target and reason code by SKU

Table 4. Connecting the planner interface to the optimum-stock policy.

8. Worked optimum-stock example

Assume an A product in an A store. Forecast weekly demand is 20 units, lead time is two weeks, review period is one week, protection-period demand is therefore 60 units, and governed safety stock is 18 units. The presentation minimum is 12 units and current inventory position is 49 units.

Step Calculation Units Interpretation
1 Protection-period forecast: 20 x 3 weeks 60 Expected demand before the next effective review
2 Add governed safety stock 18 Protects demand and lead-time uncertainty
3 Target inventory position 78 60 forecast + 18 safety stock
4 Current inventory position 49 On hand + eligible inbound - commitments
5 Calculated net need 29 78 target - 49 current
6 Pack rounding 30 Order pack is 6 units
7 Maximum-WOS test Pass Result remains below the 8-WOS ceiling

Table 5. Illustrative optimum-stock calculation for one SKU-location.

Result

Replenish 30 units if supply and capacity are available. The recommendation should be reduced or deferred if a transfer can meet the need faster or if the style is entering winddown.

Network rebalancing example

SKU From From WOS To To WOS Action rationale
A item Store 101 1.6 Store 205 11.2 Protect A/A service and avoid new buy
B item Store 205 1.9 Store 318 8.4 Improve service within transfer-cost threshold
C item Ecommerce hub 3.1 Store 101 13.0 Consolidate tail demand and release space

Table 6. Illustrative network actions after min-max and ABC evaluation.

9. Governance, measurement and implementation

The policy should be transparent and merchant-controlled. Parameters must have owners, version history and effective dates. Recommendations should explain the forecast, service target, safety stock, WOS band, ABC classes, capacity effect and alternative source.

Parameter Examples Owner
Service targets Product ABC x store ABC x lifecycle Merchandise planning
Safety-stock method Demand variance, lead-time variance, z factor Planning / data science
WOS policy Minimum, target and maximum bands Planning / purchasing
Capacity Style, SKU and unit limits Store operations
Cost model Lost margin, carrying, transfer, markdown Finance
Exceptions Launch, strategic, display, exit Merchandising
Approval rights Auto, merchant review, executive exception Governance owner

Table 7. Governed parameters for a controlled optimization process.

Balanced performance measures

Service Inventory productivity Decision quality
In-stock % by ABC matrix Inventory turns Recommendation acceptance
Unit fill rate Average WOS and excess WOS Realized benefit vs predicted
Stockout duration Markdown and aged-stock exposure Override reason and outcome
Complete color-size availability GMROI / return on inventory Forecast and safety-stock accuracy

Table 8. Measure service and inventory productivity together; improving one while damaging the other is not optimization.

Appendix: concise optimum-stock rules

Rule Operational meaning
Optimum stock Lowest feasible inventory position that meets governed service and presentation requirements.
Safety stock Buffer for uncertainty, not a substitute for poor forecasting or unreliable lead time.
Minimum WOS Replenishment trigger or starvation threshold.
Target WOS Desired post-action coverage.
Maximum WOS Ceiling that prevents excess and prompts transfer or markdown review.
Product ABC Ranks economic and service importance of stock.
Store ABC Ranks local productivity, strategic role and fulfilment value.
Service matrix Sets differentiated targets for product-store combinations.
Network first Transfer usable excess before buying when economics and timing support it.
Turns Annualized cost of sales / average inventory at cost; keep bases consistent.
Human control High-impact actions require transparent reasons and approval.

Table 9. High-level policy summary.

Core formulas

WOS = available inventory / expected weekly demand.

Reorder point = protection-period forecast + safety stock.

Target inventory position = forecast through protection period + safety stock, adjusted for presentation and policy constraints.

Inventory turns = annualized cost of sales / average inventory at cost. A retail-value turns measure may also be used, but numerator and denominator must use the same valuation basis.