Maintained Markup (MMU) Formula
How apparel brands calculate maintained markup — the margin that survives markdowns, allowances and returns — and illustrative ranges to read it against.
What Maintained Markup measures
Maintained markup is the margin that actually landed — the percentage of net sales that remained gross margin after markdowns, allowances, and returns. If IMU is the margin you start with, MMU is the margin you keep.
MMU % = (Net Sales − COGS) ÷ Net Sales × 100The gap between IMU and MMU is the story of the season. A small gap means the plan held. A big gap means markdowns, returns, or cost overages consumed margin the pricing architecture was supposed to protect. Which reductions sit in that gap, and how large an IMU each category needs to absorb them, differs by vertical — markup and pricing by vertical sets out the bridge across ten of them.
Worked apparel example
A DTC brand sold $840K in net sales (after returns) for the Tops department in a season. COGS for those units was $370K.
MMU % = ($840K − $370K) ÷ $840K = 56.0%
IMU for the department was 62%. The 6-point gap is the cost of the season: markdowns taken, allowances granted, returns reduced net sales, and cost overages on a few styles. As an illustrative reference point, not a published benchmark, a DTC IMU-to-MMU gap of 6–10 points is the range to start from until you have your own history. Past ten points, the gap signals markdown trouble.
MMU of 56.0% is strong — markdowns and returns stayed in line with plan.
Illustrative planning ranges
Illustrative reference points, not a published benchmark — set targets from your own history.
Failure modes we see
MMU measured only at season close. By the time the report lands in the post-mortem deck, the season is done. The planning team finds out in March that Fall's MMU missed by 4 points — and every decision that caused it is locked in.
Specific patterns:
- No in-season MMU tracking. MMU drift only surfaces at hindsight. In-season reads of running IMU + markdown would flag the trajectory weeks earlier.
- Returns excluded. MMU calculated on gross sales, not net. Restocked returns take their cost out of COGS but leave their revenue in a gross-sales figure, so the error grows with the return rate — in the illustrative Tops example above, a 20% return rate turns a true 56.0% into 64.8%. Markdowns work the same way: measure sales at original ticket instead of the price each unit actually sold for, and MMU is overstated again.
- Wholesale allowances missed. Off-invoice allowances, chargebacks, and markdown money reimbursed to accounts often land in a different GL and get missed in the MMU roll-up.
How RetailNorthstar handles MMU
MMU runs live in a connected planning system. As markdowns are taken, returns processed, and allowances booked, the system recalculates MMU against plan at department, class, and style level. Drift is flagged before it becomes hindsight.
The IMU-to-MMU gap measures how well the merchandising plan held. A tight gap means buy depth, pricing, and assortment balance were well-matched to demand. A wide gap means the plan broke somewhere — and connected data is the only way to trace it to the specific styles, sizes, or channels that caused it.
Related formulas
- Initial Markup — the starting margin MMU drains from
- Markdown % — the primary drain on IMU-to-MMU
- GMROI — combines MMU with inventory efficiency
See how RetailNorthstar tracks IMU-to-MMU drift live by department, class, and style.
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Frequently asked about Maintained Markup % (MMU)
What is the MMU formula?
MMU % = (Net Sales − COGS) ÷ Net Sales × 100. Net sales is the critical input — it is post-return, post-allowance, post-markdown, which is why MMU is the honest margin measure for a season.
What is a healthy IMU-to-MMU gap?
As an illustrative reference point, not a published benchmark: a 6–10 point gap between IMU and MMU for DTC. Set your own from prior seasons. A gap over 10 points comes from heavy markdown, fit issues driving returns, or cost overages; under 6 points usually means tickets were under-marked or full-price selling ran longer than planned.
Do returns count against MMU?
Yes. Returned units reduce net sales, the denominator in MMU. When a returned unit goes back into stock, its cost comes out of COGS too — so MMU run on gross sales keeps the returned revenue in while the matching cost is already gone, and the overstatement grows with the return rate. Illustratively, on the Tops example on this page ($840K net sales, $370K COGS, 56.0% MMU), a 20% return rate means $1,050K of gross sales: ($1,050K − $370K) ÷ $1,050K = 64.8%, overstating MMU by 8.8 points.
Can MMU be tracked in-season?
Yes, and it should be. Reviewed only at season close, MMU arrives after every decision that caused the miss is locked in. In-season MMU — recalculated weekly as markdowns, returns, and allowances land — lets teams intervene before hindsight.