U.S. Bank Account Number

Detects U.S. Bank Account Number patterns. This pattern is based on a Microsoft Purview built-in sensitive information type. Financial account numbers require corroborative evidence for reliable detection due to their generic numeric format.

Type

regex

Engine

universal

Confidence

low

Confidence justification

Low confidence: eight to seventeen digit numbers are extremely common in all contexts. Banking keywords such as 'account number' or 'checking' are essential for reliable US bank account detection.

Detection quality

Verified

Jurisdictions

us

Regulations

CCPA/CPRA, FTC Act s5, GLBA, HIPAA, SOX, State Breach Laws (US)

Frameworks

ISO 27001, ISO 27701, PCI-DSS, SOC 2

Data categories

pii, financial

Scope

narrow

Risk rating

8

Platform compatibility

Purview: Compatible, GCP DLP: Compatible, Macie: Compatible, Zscaler: Compatible, Palo Alto: Compatible, Netskope: Compatible

Pattern

\b\d{8,17}\b

Corroborative evidence keywords

bank account, account number, checking, savings, routing, ACH, bank account number, savings account, [object Object], [object Object], [object Object], banking, [object Object], chequing, financial institution, Kiwibank, Westpac, חשבון בנק, מספר חשבון, סניף (+16 more)

Proximity: 300 characters

Should match

• 12345678 — Eight-digit US bank account number
• 12345678901234567 — Seventeen-digit US bank account number
• 9876543210 — Ten-digit US bank account

Should not match

• 1234567 — Seven digits, too short for US bank account
• 123456789012345678 — Eighteen digits, exceeds US bank account format

Known false positives

• Generic numeric sequences such as reference numbers, invoice numbers, or identifiers from other domains Mitigation: Require corroborative evidence keywords within the proximity window to distinguish financial account numbers from general numeric data.
• Phone numbers, postal codes, or other structured numbers with similar digit counts Mitigation: Layer with other detection patterns to deprioritise matches that overlap with phone number or postal code formats.

References

• U.S. Bank Account Number entity definition - Microsoft Learn