Customer concentration and churn diligence: risk memo

Prepare a customer concentration and churn diligence memo for {target_name}.

Inputs:
- Revenue by customer over time: {revenue_by_customer}
- Contract terms / renewal dates: {contract_terms}
- Churn and retention metrics: {churn_metrics}
- Customer disputes/credits: {disputes}
- Sales pipeline context: {pipeline_context}

Output:
1) Concentration metrics (top 10 %, HHI) and trend.
2) Renewal and churn risk calendar (next 12–24 months).
3) Key contract risks (termination, pricing, SLAs) and evidence needed.
4) Implications for valuation and working capital.
5) Questions for management.

Use tables and concise risk bullets.