---
title: "Creating a Taxonomy Extension"
description: "Company­specific disclosures not available in the standard taxonomy must be reported as 'taxonomy extensions'. Furthermore, what are referred to as 'anchors' must be used to specify the present taxonomy items to which the extension is semantically connected."
source_url: https://support.lucanet.cloud/en/documentation/xbrl-tagger/xbrl-document/xbrltagger-extend-taxonomy
language: en
last_updated: 2023-08-16
---
# Creating a Taxonomy Extension

## Overview

Companyspecific disclosures not available in the standard taxonomy must be reported as **taxonomy extensions** (extension elements). Furthermore, what are referred to as **anchors** must be used to specify the present taxonomy items to which the extension is semantically connected.

{% warning-box %}
A taxonomy extension is permitted only if the taxonomy does not contain a suitable element and the core element of the taxonomy would result in misrepresentation.
{% /warning-box %}

## Creating an Extension

To create an extension:

{% stepper %}
{% stepper-step %}
Select the cells that belong to the extension.
{% /stepper-step %}
{% stepper-step %}
Click **Add Extension** in the header of the document:

'Add Extension' button

{% /stepper-step %}
{% stepper-step %}
Edit the properties of the extension in the **Fact Properties** area:

Properties of an extension

{% /stepper-step %}
{% stepper-step %}
Create and configure an anchor (see [Adding and Configuring an Anchor](#anchoring)).

{% /stepper-step %}
{% /stepper %}
{% warning-box %}
The created extension must be linked to the core taxonomy. What are referred to as **anchors** are created for this purpose. There are two different types of anchors:

- **Narrow anchor**: element of the core taxonomy with a narrower accounting meaning than the extension element. Any number of narrow anchors may exist.
- **Wide anchor**: element of the core taxonomy with a broader accounting meaning than the extension element. Only one wide anchor may exist at a time.
{% /warning-box %}

## Adding and Configuring an Anchor

To perform the anchoring, the respective tags must be inserted and configured under **Properties**. To anchor an extension:

{% stepper %}
{% stepper-step %}
Select the extension you want to anchor.
{% /stepper-step %}
{% stepper-step %}
Scroll to the very bottom of the **Properties** area.
{% /stepper-step %}
{% stepper-step %}
Drag the respective tag from the taxonomy and drop it onto the **Drop anchor element here** field.

Field used to set an 'anchor'

{% /stepper-step %}
{% stepper-step %}
Configure the anchor by defining whether it is a **narrow** or **wide** anchor. Bring the respective slider into the corresponding position for this purpose.

Wide and narrow anchor

{% /stepper-step %}
{% /stepper %}
{% info-box %}
An extension may always only have **one wide**, but **several narrow** anchors.
{% /info-box %}