How CFI codes affect MiFIR fields 42–56

A narrow answer

What the mapper answers

For a recognised six-character CFI, the workbench finds the relevant pattern in the UK FCA Transaction Reporting Validation Rules and shows the CFI-dependent status of fields 42 to 56.

It is designed for questions such as: “For this instrument classification, which descriptive fields are mandatory, optional or not applicable?” It does not attempt to decide whether the transaction itself is reportable.

Decision context

First decide whether the CFI rules apply

The FCA validation rules state that fields 42–56 are not applicable where a transaction is executed on a trading venue or with an investment firm acting as a systematic internaliser, or where field 41 contains an ISIN that exists in the reference data list.

The workbench requires an explicit context selection before presenting the CFI-dependent mapping. If either side of that condition applies, select “Fields not applicable”. Otherwise, select “Apply CFI rules”.

Method

How the code is matched

The FCA workbook expresses the validation logic as CFI patterns. Asterisks act as wildcards. For example, ES**** matches recognised common or ordinary equity-share classifications beginning with ES.

Where more than one pattern could match, the workbench selects the most specific pattern, meaning the one with the greatest number of fixed characters. The matched FCA pattern is displayed above the table so the result can be checked.

Reading the result

Status meanings

Use the filter controls to isolate mandatory or applicable fields. “Copy mandatory fields” produces a compact working list; “Export CSV” downloads all 15 statuses with the CFI and matched pattern.

Coverage

The 15 transaction-report fields

Governance

Limits, date and source

The current local data was generated from the FCA Transaction Reporting Validation Rules with an applicable date of 19 March 2026. The mapping is deliberately limited to CFI-dependent statuses for fields 42–56.

It does not determine reportability, test every field in a transaction report, establish whether an ISIN appears in the reference-data list, or predict whether an ARM submission will be accepted. Firms should apply their own controls and use the official FCA transaction-reporting resources as the authority.