> ## Documentation Index
> Fetch the complete documentation index at: https://docs.rook.pm/llms.txt
> Use this file to discover all available pages before exploring further.

# Exact payouts

> Selected outcomes as rows, published scenarios as columns.

[`POST /payouts:calculate`](/api-reference/calculate-payouts) answers two questions: when each selected outcome pays, and what those outcomes pay in selected scenarios.

```json theme={null}
{
  "selection": [
    {
      "outcome_id": "out_fed_dec_2026_cut_yes"
    },
    {
      "outcome_id": "out_fed_dec_2026_hold_yes"
    }
  ],
  "scenario_pins": [
    {
      "family_id": "fam_fed_dec_2026",
      "scenario_version": "1"
    }
  ]
}
```

Omit `scenarios` to request applicable columns. Supply issued scenario references to restrict the domain. The service returns rows only for the supplied outcomes.

## Read the matrix

Every matrix carries ordered `scenario_columns`, selected `rows`, `total_column_count` and a representation. A row identifies its outcome, optional listing, currency, payout unit and aligned exact values.

Financial decimals are strings. Repeating exact values use a rational object:

```json theme={null}
{"numerator": "1", "denominator": "3"}
```

Preserve exact values through calculations. Round only for display.

## Page through columns

`next_page_token` continues the same selection, filters and pinned versions. Keep those inputs unchanged across pages. A page is not the full scenario domain; use `total_column_count` and the continuation token to track completeness.

For a payout matrix `F`, terminal portfolio payout in scenario `s` is `sum(q[i] * F[i,s])`. Position conventions determine whether quantities receive or owe the payout. Use [evaluation](/guides/exposure) when you need quantities, attribution or candidate impact.

<Note>
  Terminal payout is a settlement amount. It is separate from a current mark, expected value and historical-entry P\&L.
</Note>


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