---
title: "How do I create a reconciliation rule?"
slug: "how-do-i-create-a-reconciliation-ruleset"
updated: 2025-07-04T16:26:49Z
published: 2025-07-04T16:26:49Z
canonical: "support.lusid.com/how-do-i-create-a-reconciliation-ruleset"
---

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

# How do I create a reconciliation rule?

You can create a reconciliation rule to define the data to compare for a holding, transaction, or valuation reconciliation.

**Recommended reading:** [Understanding reconciliation rules in LUSID](/v1/docs/understanding-reconciliations-in-lusid#rulesets)

## Methods

LUSID web appLUSID API

1. Navigate to **Reconciliations > Configuration**, and select the **Rules** tab.
2. Click the **Create reconciliation rules** button and populate the form. ![](https://cdn.document360.io/d575ad81-c0ed-4980-bbd1-d59ac5c3de82/Images/Documentation/image(843).png)

Call the [CreateComparisonRuleset](https://www.lusid.com/docs/api/lusid/endpoints/group-reconciliations/CreateComparisonRuleset) API, for example:

```json
curl -X POST "https://<your-domain>.lusid.com/api/api/reconciliations/comparisonrulesets"
  -H "Authorization: Bearer <your-API-access-token>"
  -d "{
  "id": {
    "scope": "Finbourne-Examples",
    "code": "HoldingUnitsRule"
  },
  "displayName": "Compare holding units",
  "reconciliationType": "Holding",
  "coreAttributeRules": [
    {
      "left": {
        "key": "Instrument/default/Ticker",
        "operation": "Value"
      },
      "right": {
        "key": "Instrument/default/Ticker",
        "operation": "Value"
      },
      "allowableStringMappings": [
        {
          "leftValue": "MSFT",
          "rightValue": "MSF",
          "direction": "UniDirectional"
        }
      ],
      "isComparisonCaseSensitive": false
    },
    
  ],
  "aggregateAttributeRules": [
    {
      "left": {
        "key": "Holding/Units",
        "operation": "Value"
      },
      "right": {
        "key": "Holding/Units",
        "operation": "Value"
      },
    }
  ]
}"
```

## Fields

### Core attributes

Each rule must include one or more core attributes. The left and right core attributes define how to join the left and right sides of the reconciliation, ready for comparison.

### Aggregate attributes

Each rule must include one or more aggregate attributes. The left and right core attributes define the values to compare and reconcile.

![](https://cdn.document360.io/d575ad81-c0ed-4980-bbd1-d59ac5c3de82/Images/Documentation/image(925).png)

## Updating a reconciliation rule

Once created, you can click the **Edit** icon to update a reconciliation rule. ![](https://cdn.document360.io/d575ad81-c0ed-4980-bbd1-d59ac5c3de82/Images/Documentation/image(844).png)

When you update a rule:

- All subsequent reconciliation runs that use the rule will use the updated version.
- Reruns of an existing reconciliation instance that use the rule will use the updated version.