This rule detects suspicious patterns of identical-amount transactions that are statistically unlikely in legitimate commerce.

Triggers when:
1. Multiple transactions share exact same amount
2. Concentration exceeds normal business expectations
3. Pattern suggests systematic rather than random occurrence

Identical amounts are suspicious because:
- Real customer purchases naturally vary in amount
- Common in card testing (fraudsters use same test amount)
- Money laundering indicator (moving specific sums)
- Merchant fraud (processing predetermined fake transactions)
- Subscription fraud (unauthorized recurring charges)

Pattern analysis is important because:
- Single matching amount may be coincidence
- Multiple identical amounts indicate systematic activity
- Suggests automated fraud tools or coordinated scheme
- Enables detection of fraud rings using standardized amounts

System evaluates:
- Frequency of amount repetition
- Time distribution of matching amounts
- Merchant type appropriateness (subscriptions vs. retail)
- Geographic distribution of identical amounts

Alert allows investigation of:
- Transaction legitimacy and supporting documentation
- Merchant business model validation
- Customer identity verification for matching amounts
- Pattern correlation with known fraud schemes