Standards
Market Identifier Code (MIC)
An ISO code for a trading venue or market segment.
- Kind
- Identifiers
- Steward
- ISO 10383; SWIFT as registration authority
- Official source
- https://www.iso20022.org/market-identifier-codes
What it describes
A Market Identifier Code identifies an exchange, trading platform, or relevant market segment under ISO 10383. MICs let trade and instrument records state where an activity occurred or a quotation was sourced. The standard distinguishes operating MICs from segment MICs. That distinction matters when several segments belong to one operating venue and a record needs the level actually reported by its source.
A MIC is not a security identifier and does not establish that a particular instrument was listed or traded at a given time. Venue names and segments can change. A record using a MIC should retain the source and relevant date, then verify status against the maintained MIC list when historical market context matters. Combining MIC with an instrument identifier supports a more precise trading-context reference.
Structure
Four-character alphanumeric code; operating and segment MICs are separately recorded.
Useful for
- Identify a reported trading venue.
- Distinguish market segments.
- Contextualize instrument and transaction data.
Limits
- Not an instrument identifier.
- Does not prove a specific trade occurred.
- Venue status can change over time.
How it is used in practice
Trade reports, best-execution reviews and market-surveillance files all need to say where something happened. A MIC supplies the where. It is used in transaction reporting to identify the venue of execution, in reference data to state the listing venue of an instrument, and in market-data feeds to separate quotes from different venues for the same security. The ISO 20022 registration authority maintains the list of codes publicly, with fields for the operating venue, the segment, the country, the status and the dates on which a code was created or changed.
The operating MIC and the segment MIC play different roles. An exchange that runs separate order books or trading models for different products may have one operating MIC and several segment MICs. Records are most useful when they say which level they carry, because "traded on the exchange" and "traded in this segment of the exchange" can matter differently for a regulatory test.
A worked example
A fictional exchange, the Halden Exchange, operates a main market and a growth market. Its operating MIC covers the exchange as a body, while two segment MICs distinguish the main and growth markets. A fund's trade file records one trade with the operating code and another with a segment code.
A reviewer who wants to test whether both trades happened on the same venue consults the registered list and finds that both codes share one operating MIC. A reviewer who wants to test whether the second trade was on the growth market needs the segment code, and the first record cannot answer that question. The finding is recorded as a bounded statement: the first trade is attributed to the Halden Exchange at operating level; its segment is not recorded in the source. That is a declared unknown, not an assumed main-market trade.
Evaluating a claim that rests on a MIC
Look up the code in the maintained list rather than in a copy of unknown age. Codes are added, retired and sometimes reassigned in their descriptive fields as venues merge, change owners or close, so a historical record needs the status of the code at the relevant date, not merely today's status. Where the question is whether a venue was operating on a given day, the MIC list is a starting point and the venue's own notices or the regulator's register provide the stronger evidence.
A MIC says nothing about whether a particular instrument was admitted to trading there. For that claim the pair of instrument identifier and MIC has to be found in a listing or trading record. Combining an ISIN with a MIC and a date gives a defensible reference to a listing at a moment; either alone does not.
Confusions to avoid
A MIC is not a country code, a ticker suffix or an LEI for the operator. Country codes classify geography and are governed by ISO 3166. A ticker suffix such as a dot and a letter is a convention that differs between data vendors. An LEI identifies the legal entity that operates a venue, whereas the MIC identifies the venue or segment itself. The two can be linked, and a link is a statement with a source and a date.
A further confusion treats venue codes as stable names. Venues rebrand, merge and close, and a code may stay while the operating firm changes. Anything that depends on who operated a venue at the time of a trade needs a dated operator link. The record should also keep both the MIC as it appeared in the source and the code after normalization, because upstream systems sometimes substitute a default code when the true venue is not provided.
Questions a reviewer can ask
Is the code an operating MIC or a segment MIC? What is its status in the registered list, and on what date? Was the code taken from the venue's own report, or substituted by an intermediary? Does the claim require that the instrument was admitted to trading there, and if so, is there a listing record? If the venue has since changed operator or closed, does the record keep a dated link that explains it?
Related terms
Found an error on this page? See corrections for what counts as one, how to report it and the dated log.
Enquiry
Which of your sources carry Market Identifier Code (MIC)?
Tell us which sources carry it, which key the same entity some other way and who may read which. We reply with whether and how a first record would use this identifier.
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