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SEDOL

SEDOL (Stock Exchange Daily Official List) check digit calculation. 7-character alphanumeric identifier for securities on London Stock Exchange. Uses weighted sum modulo 10 with specific character mappings. Position 7 is check digit (0-9).

Properties

Property	Value
Category	Checksums
Sub-category	Financial Identifier
Security status	🎓 Educational Only
Complexity	Intermediate
Inventor	London Stock Exchange
Year	1979
Origin	🇬🇧 United Kingdom
Source	algorithms/checksum/sedol-checksum.js

Security

Status: 🎓 Educational Only

No vulnerabilities are recorded for this implementation.

Notes

• Format: 6 alphanumeric + 1 check digit
• Character values: 0-9 = numeric value, A-Z = 10-35 (excluding vowels)
• Weights: 1,3,1,7,3,9 (positions 1-6)
• Algorithm: Σ(character_value × weight) mod 10
• Check digit: (10 - sum mod 10) mod 10
• Used for: UK and Irish securities
• Complements: ISIN (international), CUSIP (North America)
• Detects: All single-character errors
• Example: 0263494 (Barclays Bank)

Documentation

• SEDOL on Wikipedia
• London Stock Exchange
• SEDOL Masterfile

References

• python-stdnum SEDOL implementation

Test vectors

3 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — BAE Systems (0263494)

Field	Value
input	303236333439
expected	04

Vector 2 — SEDOL 406566 (4065663)

Field	Value
input	343036353636
expected	03

Vector 3 — SEDOL B0YBKJ (B0YBKJ7)

Field	Value
input	423059424b4a
expected	07

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