---
title: "Supplemental feed label: meaning | Product Metrics"
description: "A custom label can be supplied by a Merchant Center supplemental data source. See how ID matching works and how it differs from Merchant Center feed labels."
canonical: "https://www.productmetrics.io/glossary/supplemental-feed-label"
pageType: article
language: en
publisher: "Product Metrics"
author: "Berend Vrakking"
datePublished: 2026-10-15
dateModified: 2026-10-28
---

> Content index: https://www.productmetrics.io/llms.txt

# Supplemental feed label

A supplemental feed label is this glossary’s name for a custom label whose value is supplied by a Merchant Center supplemental data source.

## Supplemental feed label example

Adding a performance group:

| Field | Value |
| --- | --- |
| Existing product ID | shoe-001 |
| Custom label field | custom_label_0 |
| Supplemental value | stars |

The matched product keeps its primary product data while receiving a group value for campaign organisation. Illustrative data.

## Put it into practice

- [Explore it: Product Segmentation](https://www.productmetrics.io/product-segmentation): Turn approved groups into Merchant Center labels.
- [Read the guide: Optimise Google Shopping ads](https://www.productmetrics.io/blog/optimize-google-shopping-ads): Connect product data and campaign management.

## Supplemental feed label: one product and the whole account

The label belongs to the matched product. Products with the same value can be grouped in campaign reporting or configuration. Check matching and source rules before relying on the group; a label on the wrong item changes its meaning.

Custom labels can describe margin bands, seasonality or performance groups. Product Metrics uses approved Merchant Center labels to carry segmentation into configured campaigns. Keep the label meaning consistent across your products.

## Supplemental feed label: common mistake

Treating this as a Google term or confusing it with Merchant Center feed labels. Google’s feature is the supplemental data source, which can add or override custom labels for products that already exist in a primary source.

## Supplemental feed label: questions

### Is this a separate Google attribute?

No. Google has no attribute called a supplemental feed label. The term describes a custom label, one of the five attributes custom_label_0 to custom_label_4, whose value comes from a supplemental data source. Google’s own wording is supplemental data source, and feed labels are a separate Merchant Center setting.

### Does adding a label change campaign priorities?

No, not by itself. A label only changes how products are grouped. Campaign priorities change only when your campaign configuration splits on that label, for example in Standard Shopping product groups or listing groups within Performance Max asset groups. Supplying the label data does not define your advertising strategy, so you set the priorities yourself.

## Sources

- [Google Merchant Center Help: Create a product data source](https://support.google.com/merchants/answer/14990942?hl=en)

## Keep reading

- [Custom labels](https://www.productmetrics.io/glossary/custom-labels): Understand the product attributes being populated.
- [Supplemental feed](https://www.productmetrics.io/glossary/supplemental-feed): Understand the source that adds the label.

---

Written by Berend Vrakking, founder of Product Metrics. Last updated 2026-10-28.

HTML version: https://www.productmetrics.io/glossary/supplemental-feed-label