Definition
The Bing Index is Microsoft's web index, which powers Bing search results and has historically been a retrieval backbone for ChatGPT Search. Because ChatGPT citations have overlapped heavily with Bing's top results, Bing visibility is a useful leading indicator for citation share on ChatGPT, making it relevant to GEO alongside Google AI Overviews.
The relationship is not static. OpenAI has expanded its own indexing and retrieval, so the Bing overlap has shifted over time, but Bing visibility remains a practical signal for ChatGPT AI search work. Brands that rank well on Bing for a query tend to appear in ChatGPT citations for that query more often than chance, which is why our ChatGPT SEO guide treats Bing as part of the ChatGPT retrieval picture.
For SEO and GEO teams, track Bing rankings for your target prompts alongside ChatGPT citation share, and watch for divergence that signals OpenAI is moving away from Bing retrieval. Use Bingbot crawl data to confirm Bing can access your content, and ensure crawling and indexing fundamentals are solid.
Bing also feeds Microsoft Copilot, so Bing visibility supports Copilot citations in addition to ChatGPT.
Examples of Bing Index
- A brand tracks Bing rankings and ChatGPT [citation share](/glossary/citation-share) side by side and finds Bing visibility leads ChatGPT citations by about two weeks.
- A GEO team reads the [ChatGPT SEO guide](/blog/chatgpt-seo) and adds Bing tracking to its ChatGPT workflow.
- A site owner confirms [Bingbot](/bots/bingbot) can crawl its site after a redesign to protect Bing-driven ChatGPT citations.
- A team notices ChatGPT citations diverging from Bing results and infers OpenAI is expanding its own retrieval.
