Short answer
Revenue concentration risk means one or a few customers now carry too much of the revenue base. That makes retention, forecasting, and negotiating leverage materially more fragile.
What it usually means
The problem is not only customer size. It is dependence. When a small number of accounts dominate ARR, one downgrade, churn event, or renewal dispute can distort the whole company picture.
Main causes
- The company landed a few enterprise accounts faster than it diversified the base.
- Expansion accumulated inside existing large accounts while new logo mix stayed narrow.
- SMB or mid-market acquisition slowed, increasing enterprise concentration mechanically.
- Reporting does not surface customer-share concentration until risk is already elevated.
What to check next
- Check ARR and MRR by customer segment rather than only totals.
- Open Portfolio Demo to inspect account mix and dependency at the customer layer.
- Compare broad concentration with Single Whale Risk, NRR, and Expansion MRR Is Slowing.
Product angle
Concentration risk is manageable only when revenue mix is visible before renewal season forces the issue. That requires customer-level analytics, not just top-line dashboards.