Gross merchandise value is the most quoted number in commerce and one of the least policed. PPC Land’s new explainer lays out what GMV actually measures: the total value of goods and services transacted through a platform in a period, struck before the platform’s fees, usually before returns, and in some definitions before anyone confirms the buyer paid.
It counts what moved. Not what was earned.
Why marketplaces invented it
A retailer that buys stock and resells it can describe its scale with revenue. A marketplace taking a commission on someone else’s sale cannot, because revenue may be a low single-digit slice of the activity it hosts. GMV describes the activity; the take rate converts it into a business.
The maths is simple: price times units, summed. A platform processing 1,000 orders at 50 dollars records 500,000 dollars of GMV. At a 10% commission, that is 50,000 dollars of revenue.
What is not simple is the inclusions. Per the explainer, buyer-paid shipping is in for some platforms and out for others. Sales tax varies. Discounts may be deducted or ignored, which means a 40% promotion either slashes GMV or leaves it untouched depending on whether list or paid price is counted. Cancellations and returns are almost never deducted, because the number is struck at order placement.
No accounting standard defines GMV. No auditor signs it. eBay counted closed transactions regardless of whether the buyer ever paid until 15 December 2021, when it moved to paid transactions inclusive of shipping and taxes and restated history, calling the impact immaterial. Alibaba’s FY2016 20-F excluded certain high-value category transactions and buyers above a daily threshold as a guard against potentially fraudulent activity — policy choices, not rules. The SEC addressed the wider issue with interpretive release 33-10751 in January 2020, asking companies to define their KPIs and explain how they are used.
Three places GMV hits your job
For performance marketers, this is not investor trivia. GMV shows up in three roles:
- Denominator. Retail media is sized against the commerce beneath it. Walmart CFO John David Rainey said in February 2026 that Walmart Connect ad revenue as a share of GMV stayed in the mid to low single digits, while the global ad business grew 46% to nearly 6.4 billion dollars. Shopify’s merchant solutions attach rate hit 2.14% of GMV in Q3 2022.
- Billing base. Affiliate and offsite retail media charge against order value, not media spend. Etsy’s Offsite Ads take 15% of an attributed order below a 10,000 dollar annual threshold and 12% above, capped at 100 dollars per order. impact.com reported roughly 120 billion dollars of partner-referred GMV in 2025 across about 350,000 active partnerships — commerce tracked, not money collected.
- Bid target. TikTok’s GMV Max optimises straight to merchandise value and attributes orders on advertised products to the campaign, including orders that started in organic content or affiliate activity.
Where it breaks
GMV rewards inflation. Returns and cancellations sit outside the headline while revenue does not, so a platform — or a seller — can grow merchandise value through discounting and category mix while margins sink.
TikTok effectively conceded the point. GMV Max Pro, announced 28 July 2026, extends optimisation beyond ad spend to coupons, affiliate costs and platform commissions, because optimising to top-line GMV ignores discount depth and payouts. You can hit the GMV target and lose money per unit.
Coverage is the second gap: TikTok Shop’s off-site tool tracks D2C and Shopify sites only, so a low off-site ratio may describe the measurement, not the market. Comparability is the third — two platforms reporting 20% GMV growth may be counting different things.
What to do about it
Write your own definition and hold it. Decide whether shipping, tax and discounts are in. Track net merchandise value alongside GMV so returns and cancellations are visible. When a platform optimises to GMV, pair it with a contribution-margin guardrail. And when you benchmark a competitor’s number, check the footnote before you trust the trendline.
The stakes keep rising. Shopify said on 5 May 2026 that merchants transacted more than 100 billion dollars of GMV in a single quarter. Omdia projects retail media will take roughly 20% of global ad revenue by 2030, above 300 billion dollars — all priced against a merchandise base nobody audits.
Source: PPC Land
