Inventory Turnover › GMROI
GMROI: Gross Margin Return on Inventory Investment
GMROI tells you how many dollars of gross profit you earn for every dollar invested in inventory. A GMROI of 2.0 means $2 of gross margin for every $1 of average inventory at cost. Most retail sectors operate between 1.0 and 4.0; the spread reflects the trade-off between margin and velocity.
Formula
GMROI = Gross Margin $ ÷ Average Inventory at Cost
or, equivalently:
GMROI = Gross Margin % × Sales / Average Inventory at Cost
GMROI = Gross Margin % × (Inventory Turnover × (1 / (1 - GM%)))
The simplest decomposition: GMROI is approximately gross margin times turnover times (1 / (1 minus gross margin)). High-margin slow-turn (jewelry) and low-margin fast-turn (grocery) can hit the same GMROI by different routes.
Worked example: apparel buyer
An apparel buyer is reviewing two SKUs for the spring assortment.
SKU A: Premium dress
- Retail price: $180
- Cost: $72 (60% GM)
- Expected turn: 2.5x / year
- GMROI = 0.60 × 2.5 / 0.40 = 3.75
SKU B: Mass T-shirt
- Retail price: $24
- Cost: $14.40 (40% GM)
- Expected turn: 7x / year
- GMROI = 0.40 × 7 / 0.60 = 4.67
The mass T-shirt has the higher GMROI despite a lower margin. The buyer should consider both, with floor space allocation reflecting GMROI rather than gross margin alone.
Sector benchmark table
Derived from public 10-K filings, gross margin and inventory turnover combined. All figures fiscal 2024 / 2025.
| Sector | Gross Margin | Turnover | GMROI | Note |
|---|---|---|---|---|
| Grocery / Supermarket | 27% | 14x | 3.78 | Low margin offset by high turnover. |
| Apparel | 45% | 3.5x | 1.58 | Premium pricing compensates slower turn. |
| Electronics specialty | 23% | 6x | 1.38 | Thin margin, moderate turn. |
| Home improvement | 33% | 4.5x | 1.49 | Pro mix raises both margin and turn. |
| Auto parts aftermarket | 52% | 1.5x | 0.78 | Slow turn dominates; gross margin pulls GMROI low. |
| Furniture (luxury) | 47% | 1.4x | 0.66 | Acceptable because store / brand economics support it. |
| Warehouse club | 13% | 12x | 1.56 | Tiny margin, huge turn; comparable to apparel GMROI. |
| Jewelry | 44% | 1.5x | 0.66 | Display-driven model; member services subsidise. |
Sources: SEC EDGAR 10-K filings, cross-referenced with the sector pages linked below.
Using GMROI to set buying targets
Category managers use GMROI to set assortment-level minimum thresholds. A typical retail process:
- Establish a category GMROI target (often 2.0-3.0 for general merchandise).
- Calculate trailing-12-month GMROI for every SKU in the category.
- SKUs below 50% of target enter a markdown / discontinue review.
- SKUs above 150% of target get more facings, deeper inventory, more replenishment frequency.
This converts a financial KPI into an operating buying discipline. The retailers with the most disciplined GMROI processes (Costco, Home Depot, AutoZone) consistently outperform peer-group operating margins.