This rule provides tiered monitoring for ultra-high-value transactions using regionally-issued cards (GCC region), with category-specific responses.

System behavior:
1. Flags any transaction exceeding AED 1,500,000
2. Card must be regional issue (Gulf Cooperation Council countries)
3. Cat A merchants: Generate ALERT only (monitoring without hold)
4. Cat B/C/D merchants: Automatic HOLD for review

Rationale for tiered response:
- Cat A (Enterprise): Established businesses with verified high-value transaction patterns
- Cat B/C/D: Additional verification needed due to unusual transaction size for merchant tier
- Regional cards have moderate fraud risk (lower than international, higher than local)
- Amount requires enhanced validation but relationship tier matters

HOLD enables comprehensive verification including corporate authorization confirmation and business validation before releasing funds.