This rule detects sudden decreases in merchant transaction volume that may indicate business closure, fraud discovery, or operational compromise.

System flags when:
1. Merchant daily transaction volume drops significantly
2. Decrease represents substantial deviation from baseline
3. Sudden change rather than gradual decline

Sudden volume drops can indicate:
- Business closure without notification
- Fraud detection causing customer loss
- Merchant account compromise (owner locked out)
- Regulatory action or payment hold
- Catastrophic business event (fire, natural disaster)
- Merchant switching to competitor processor

Volume drop concerns include:
- Potential insolvency affecting refund/chargeback reserves
- Fraud may have damaged business reputation
- Settlement risk if business is failing
- May precede merchant abandonment
- Could indicate owner is unaware of account status

Alert enables risk management to:
- Proactive merchant contact for status check
- Business viability assessment
- Settlement risk evaluation
- Reserve adjustment if closure imminent
- Orderly account closure if business ceased
- Investigation if compromise suspected

Monitoring volume drops is critical for:
- Preventing merchant abandonment with outstanding liabilities
- Early fraud detection (customer loss after fraud)
- Payment processor risk management
- Reserve adequacy assessment
- Regulatory compliance (business status verification)

Sudden drops require immediate investigation to protect payment processor and customer interests.