# Customer ownership and omnibus custody

> Define the customer relationship, beneficial ownership, nominee and omnibus custody model, books and records, reconciliation, transfers, and customer-facing disclosures.

Every production launch must answer three questions without ambiguity: **whose customer is this, who
legally holds the security, and which record proves the end investor's entitlement?** The commercial
agreement, customer terms, custody agreement, and API implementation must give the same answer.

<Callout type="warn" title="Contract-first control">
  The API creates operational records; it does not create a legal trust, nominee appointment, or custody
  relationship by itself. Obtain jurisdiction-specific advice and execute the required broker, custodian,
  nominee, and customer agreements before accepting real money.
</Callout>

## Operating model

<FlowDiagram
  nodes={[
    { label: 'End investor', sublabel: 'beneficial owner' },
    { label: 'Partner', sublabel: 'customer experience + first-line support', tone: 'accent' },
    { label: 'MyStocks ledger', sublabel: 'sub-account attribution' },
    { label: 'Broker / nominee', sublabel: 'legal account holder where applicable' },
    { label: 'Custodian / CSD', sublabel: 'pooled market position', tone: 'success' },
  ]}
  edgeLabels={['customer terms', 'externalId + subAccountId', 'omnibus instruction', 'settled custody']}
/>

MyStocks maintains the sub-account ledger used to attribute pooled positions. The relevant regulated
broker, custodian, nominee, or CSD holds the market-level position under the arrangement approved for
that jurisdiction. A portfolio response is therefore an operational entitlement record, not a claim that
the end investor has an individually named CSD account.

## Responsibility matrix

| Control | Partner | MyStocks | Broker / custodian |
| --- | --- | --- | --- |
| Customer contract and consent | Own and retain | Provide required platform disclosures | Supply market-specific terms |
| Customer identity and authority | Verify | Enforce KYC state received through the API | Perform any required reliance review |
| Beneficial-owner attribution | Supply stable `externalId` | Maintain `subAccountId`, holdings, tax lots, and audit history | Reconcile pooled position |
| Order instruction evidence | Capture intent and disclosures | Persist request, idempotency key, quote, and execution state | Retain venue execution record |
| Asset servicing | Notify customer and collect elections | Allocate events to sub-accounts | Receive and process issuer/CSD event |
| Books-and-records requests | Coordinate customer response | Export platform ledger and event evidence | Provide custody and execution statements |

## Minimum customer record

Keep one durable customer record that connects your identity system to the MyStocks ledger:

| Field | Control purpose |
| --- | --- |
| `externalId` and `subAccountId` | Stable cross-system identity; never recycle identifiers |
| Legal name, date of birth/incorporation, jurisdiction | Customer and regulatory classification |
| Beneficial owners and controllers | Natural persons who ultimately own or control a legal customer |
| Account authority | Persons permitted to place orders or change instructions |
| Terms and disclosure versions | Evidence of what the customer accepted and when |
| Broker/custody market mapping | Executing and custody chain applicable to the account |
| Restrictions and legal holds | Freeze, deceased estate, court order, sanctions, or dispute status |

Do not store passport images, biometrics, or unnecessary source documents in free-text API fields.
Keep sensitive evidence in the approved KYC system and send only the structured assertion required by
`POST /users/{userId}/kyc`.

## Daily books-and-records control

1. Reconcile each security's pooled broker/custodian units to the sum of attributed sub-account units.
2. Reconcile cash, unsettled trades, dividends, fees, and corporate-action allocations.
3. Classify differences as timing, mapping, external statement, or ledger exceptions.
4. Prevent silent balancing entries; require an identified owner, evidence, and approval.
5. Escalate unresolved unit or cash differences before the next trading session.

Use `GET /report/reconciliation` for the platform view and compare it with the dated broker/CSD
statement. The [Custody and beneficial ownership](/partners/docs/custody) page describes the evidence
required for GA.

## Customer-facing disclosure checklist

- Identify the contracting entity and the entity providing regulated brokerage or custody.
- Explain whether securities are held in an omnibus, nominee, or individually named account.
- State how beneficial ownership is recorded and how customers receive statements and confirmations.
- Separate execution from legal settlement and explain when cash or securities become withdrawable.
- Explain the treatment of fractional entitlements, voting rights, dividends, taxes, fees, and FX.
- Describe transfer-out, account closure, death, incapacity, attachment, and insolvency procedures.
- Disclose applicable investor-compensation or protection arrangements without implying universal coverage.

## Evidence required before production

| Evidence | Owner | Release condition |
| --- | --- | --- |
| Executed custody/nominee agreement per market | MyStocks + broker/custodian | Names the account structure and asset-protection treatment |
| Approved customer terms | Partner legal | Matches the operational model and market disclosures |
| Ledger-to-custody reconciliation | Operations | `BALANCED`, with external statement date recorded |
| Transfer and insolvency playbook | Joint operations | Tested contacts, data export, and authority matrix |
| Sample statement and trade confirmation | Partner | Shows beneficial owner, instrument, fees, FX, and settlement state |

## Reference standards

- [CPMI-IOSCO Principles for financial market infrastructures](https://www.bis.org/cpmi/publ/d101.htm)
- [FATF beneficial-ownership guidance](https://www.fatf-gafi.org/en/publications/Fatfrecommendations/Transparency-and-beneficial-ownership.html)