SEDOL – Definition & Meaning

SEDOL (Stock Exchange Daily Official List) is a seven-character alphanumeric identifier assigned to securities-used primarily for instruments listed in the UK and Ireland and widely referenced globally by data vendors and brokers. It provides an unambiguous way to identify shares, funds, and other listed instruments across systems.

Key Takeaways

• SEDOL in one sentence: A unique 7-character security identifier widely used in the UK market and by global data feeds.
• Why it matters: Reduces ticker confusion, standardizes back-office processes, and supports trade settlement.
• Context/usage: Appears on market data terminals, confirmations, statements, and reference datasets; often used alongside ISIN and ticker symbols.
• Governance: Assigned and maintained centrally (e.g., via the SEDOL Masterfile).

What Is SEDOL?

SEDOL is a reference identifier for financial instruments such as equities, ETFs, funds, depositary receipts, and some fixed-income listings. It consists of six base characters plus a check digit for error detection. Although it originated for UK/Irish markets, many non-UK instruments also have SEDOLs in global vendor files, making it a common cross-reference key in portfolio and settlement systems.

How SEDOL Works (Structure & Check Digit)

A SEDOL has 7 characters (digits and capital letters). The first six identify the instrument; the seventh is a check digit computed from the first six to catch keying errors.

Check-digit (concept): compute a weighted sum of the first six characters (mapping letters and digits to numeric values), take the result mod 10, then derive the seventh character so the full code passes the modulo check.

Usage notes

• Always use uppercase and include the check digit (all 7 characters).
• Formats may include both numbers and letters; avoid adding spaces or separators.
• In many databases, SEDOL serves as the national identifier that rolls up into the ISIN structure for UK/IE instruments.

Example in Practice

A UK-listed company’s ordinary shares will have a SEDOL (e.g., XXXXXXX format: six base characters plus one check digit). The same security will also have an ISIN, and a ticker used on the trading venue. Operations teams map all three to avoid confusion in orders, positions, and reconciliations.

Benefits and Considerations

• Benefits: Precise instrument identification; cleaner security master data; fewer settlement breaks; easier vendor cross-mapping.
• Considerations: Some datasets require licensing; not all global instruments carry SEDOLs in every feed; confirm the correct line (e.g., different classes/lines may have different SEDOLs).

Related Terms

• ISIN – global 12-character security identifier used across markets.
• CUSIP – 9-character identifier used primarily in the United States and Canada.
• Ticker Symbol – exchange-level trading symbol that can be non-unique across venues.
• LEI (Legal Entity Identifier) – 20-character code that uniquely identifies legal entities (issuers, counterparties).