About ISO 20022 Messaging

Corporate Actions Messaging Specifications for ISO 20022

ISO 20022 is an international messaging standard that simplifies global business communication by creating a common language for financial information. DTC uses ISO 20022 real-time MQ messaging and files for automated electronic communication with clients. The ISO 20022 standard provides a modernized business model and platform that replaces legacy proprietary formats and files.

Access the technical documentation and supporting resources around ISO 20022 messaging. Click the tabs to explore data dictionaries, message specifications, file layouts, templates and reference guides designed to help streamline onboarding, support development efforts and ensure consistent data exchange.

Data Dictionaries
This collection of documents provides detailed mappings of event types to function / activity codes.
Announcements, Entitlements & Allocations, and Instructions – SR 2025
Corporate Action Announcements Data Dictionary SR 2025 Updated July 21, 2025 These documents list the ISO 20022 event types, as well as the ISO 20022 published data fields and mapping back to DTC function codes. Corporate Action Entitlements and Allocations Data Dictionary SR 2025 Updated May 30, 2025 These documents list the ISO 20022 event types, as well as the ISO 20022 published data fields and mapping back to DTC function codes. Corporate Action Elections Data Dictionary SR 2025 Updated October 15, 2025 These documents outline mapping for tags associated with ISO 20022 messages for Distributions Instructions to data elements associated with DTC's EDS legacy process, as well as Reorganization Instructions mapping.
ISO 20022 Messaging Specifications
Corporate Actions Messaging Specifications for ISO 20022 are intended as an implementation overview for both technical and business experts. DTCC uses the ISO 20022 Corporate Actions Message format for its Corporate Actions Announcements, Entitlements and Allocations, Instructions and Meetings data. DTCC provides messaging specifications for the standard ISO 20022 message and, when applicable, its proprietary Extension component. The specification zip files contain the following folders, when applicable:
1 Message Usage Guidelines/Excel: documents that present the logical layout of the message XML schema. There are separate documents for each XML schema – one for ISO 'core' standard message, and one for supplementary data (extension) that embeds in the standard message. The document shows the elements that will be used in the message, elements that will not be used are marked as "removed". The document also contains DTCC market practice usage for each element e.g. DTCC definitions, annotations, rules, as well as DTCC synonyms that are the DTCC names of the elements used in browser and Data Dictionary.
2 Message Usage Guidelines/pdf: Similar to the Excel document, the PDF version provides an alternative format showing the message structure, message building blocks, message components, message data types and restrictions summarization.
3 DTCC extension schemas: a plain XML schema for DTCC extensions.
4 ISO 20022 Unrestricted Schemas
ISO 20022 messages undergo annual change, maintenance each November via a "Standards Release" or "SR". Note: There are multiple message types within each of the four message categories in the table below. Please download and unzip the files.
Note that schemas for the standard ISO MX messages can be found on https://www.swift.com/ or in MyStandards.
Automating Distributions Instructions
The array of services the Depository Trust Company (DTC) offers for the processing of corporate action events include announcing details of upcoming events and providing clients with information about their entitlements, accepting and acting on their instructions, and collecting, allocating and reporting payments across various corporate action event types including distributions, redemptions and reorganizations.
How ISO 20022 Instructions Messaging Works
1 Client receives an automated ISO 20022 notification message (CANO) from DTC announcing the corporate action event. The message contains an indicator signaling that the event is eligible for ISO 20022 instruction messaging.
2 If necessary, DTC sends a follow-up ISO 20022 message informing the client of the event’s options and eligibilities.
3 Client submits an ISO 20022 instruction message (CAIN) to DTC.
4 DTC sends an ISO 20022 instruction status advice message (CAIS) back to the client.
5 DTC sends the client an ISO 20022 message (CAPA) indicating its projected payment/allocation.
6 After the client’s instructions have been processed and funds/securities are received by DTC, an ISO 20022 message (CACO) confirming the payment/allocation of proceeds is sent to the client.
Benefits of Automating the Instructions Communications Chain with ISO 20022 Messaging
Efficiency Improvements
Clients can now participate in DTC’s Voluntary DRIP program, as automation makes this high-volume election service more efficient.
Gains in timeliness through real-time messaging and straight-through processing.
Risk Reduction
Events are easily tracked and linked using a unique corporate action identifier (CA ID / COAF) that stays with the event throughout its lifecycle.
Instructions messaging enables clients to fully maximize the DTC ISO 20022 messaging flow from announcement through to allocation.
Clients can deploy by service – TaxRelief, DRIP (including Opt Outs), Optional Dividends, FCP – for a phased approach.
Because not all TaxRelief events and jurisdictions are supported, please consult with your DTC relationship manager for details about the service scope.
DTCC Tokenization Service: Corporate Actions Processing
Event Announcement
Position Capture
Entitlements Projection
Allocation
Visit the Digital Asset Solutions page for an overall introduction to the issuance and management of tokenized assets and key capabilities.
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