# DTC / Digital Securities (DTCC Ecosystem)

## Overview

DTC and DTC-related messaging cover securities post-trade and custody. Participants include broker-dealers, custodian banks, and clearing members. Directory use is often **client-owned configuration**; public directory availability is limited.

## Scope

**Identity mapping** (LEI, BIC, participant IDs) plus **contractual endpoint profiles**. Optional import from customer-managed config (files or APIs). Do **not** claim automated discovery unless an authoritative or licensed directory feed exists. Prefer routing artifacts and admin API for participant/endpoint maps.

## Identifier Taxonomy

| Type | Description | Scope |
|------|-------------|--------|
| `lei` | Legal Entity Identifier | Public/registry |
| `bic` | Bank Identifier Code (SWIFT) | Market identifier |
| `dtc.participantId` | DTC/internal participant ID | Tenant/confidential |
| `dtc.accountId` | Custody/account ID (proprietary) | Tenant/confidential |

Historical: `duns` (D&B) where still in use.

## Endpoint Profiles

| Profile | Protocol | Description |
|---------|----------|-------------|
| `dtcc-mq` | MQ | DTCC connectivity / message system |
| `sftp.*` | SFTP | File-based instructions |
| `https.*` | HTTPS/AS2/AS4 | API or EDI over HTTP |

Address format is vendor- or channel-specific (queue name, path, URL).

## Capability Taxonomy

- `securities.settlement.*` — Settlement instructions and messages.
- `securities.corpactions.*` — Corporate actions.
- `securities.assetservices.*` — Asset servicing.

Used in resolution to match service context (e.g. request for settlement instructions).

## Tenancy and Confidentiality

- **Strong tenant scoping:** DTC and account identifiers are frequently confidential. Resolution must be scoped by tenant; no cross-tenant leakage.
- **Prefer integration via client-owned configuration:** Ingest from client-provided files or APIs rather than assuming a public directory. Use [routing artifacts](../architecture/data-model.md) and admin API for participant/endpoint maps.
- **Audit:** All access to DTC-related participant and endpoint data must be audited.