- Formula
- Cohort GMV in month N / cohort month-0 GMV
- Unit
- %
- Models
- Marketplace
| best-in-class supply-side | 100%+ | a16z GMV Retention |
| average first 3 months | 80%–95% | a16z GMV Retention |
| average by month 12 | 45%–50% | a16z GMV Retention |
What it is
GMV retention (cohort) tracks the gross merchandise value generated by a cohort of marketplace participants in a given month relative to what that same cohort generated in its first (month-0) month. It is expressed as a percentage and is typically measured on the supply side.
How to calculate it
For a given cohort, sum the GMV they transact in month N, then divide by their GMV in month 0. Multiply by 100. Track this curve monthly through at least month 12 to understand the shape of decay or expansion.
Why it matters
GMV cohort retention reveals whether the marketplace is retaining its most economically valuable participants. Supply-side GMV retention above 100% at month 12 signals that existing suppliers are growing their volume — a powerful indicator of marketplace health and compounding network value. Decay below 50% by month 12 often signals a leaky marketplace that must constantly refill supply.
Benchmarks & pitfalls
Per a16z GMV Retention research, best-in-class supply-side cohorts sustain 100%+ GMV retention through month 12 and beyond. Average cohorts post 80–95% in the first three months, decaying to roughly 45–50% by month 12. Segment this by supply tier (top 10% of sellers vs. long tail) because aggregate curves can mask a healthy core masked by high long-tail churn. Also distinguish GMV retention from seller retention — a shrinking number of sellers each transacting more can produce misleading aggregate retention figures.