OpenAI ChatGPT Citation Share - May 2026

The top 20 websites ChatGPT Search cited most in May 2026, ranked by share of all citations, with notes for SEO teams working on generative engine optimization (GEO).

Based on Promptwatch data from Apr 30 - May 30, 2026. Citations tracked from real prompt responses using ChatGPT Search when triggered in the UI.

The Most Cited Domains on OpenAI ChatGPT in May 2026

May is peak Reddit: at 6.11% of all ChatGPT Search citations it commands more than eight times Wikipedia's 0.72%, and more than all 17 other tracked domains combined (roughly 3.6%). When ChatGPT wants real-world experiences and opinions, it overwhelmingly reaches for community threads.

Beyond that outlier, the field is remarkably flat: TechRadar (0.48%), arXiv (0.31%), and Reuters (0.25%) round out the top five, and nothing else clears a quarter of a percent. Citations remain widely dispersed, keeping the door open for specialized sites that nail specific questions.

What this means for you

• Audit your Reddit presence this month: search the subreddits in your niche for your brand and competitors, and start contributing real answers. At 6.11% share, Reddit is where ChatGPT looks first for first-hand opinions.
• Remember that even a 6% leader leaves roughly 94% of citations for everyone else. Structured, factual pages on your own domain that directly answer specific prompts still capture the bulk of the opportunity.
• Feed the trusted specialists: TechRadar (0.48%) and arXiv (0.31%) show expert reviews and primary research keep earning citations. Pitch reviewers in your category or publish your own original data.

OpenAI ChatGPT Citation Share April vs May 2026

Side-by-side comparison of citation share for the top domains on ChatGPT Search between April and May 2026.

What this means for you

Reddit accelerated from 4.14% in April to 6.11% in May, a 48% jump, while April's other winners fell back to earth: Walmart crashed from 0.71% to 0.19%, TechRadar eased from 0.71% to 0.48%, and Forbes halved from 0.30% to 0.14%. Meanwhile a quieter cohort gained ground: GitHub rose from 0.15% to 0.23%, LinkedIn from 0.18% to 0.23%, and Trustpilot from 0.14% to 0.18%. Outside of Reddit's runaway growth, citation share churns constantly and rewards whoever keeps their content fresh where ChatGPT is currently looking.

How to act on it

• Treat single-month spikes with caution before betting your roadmap on them: Walmart doubled in April and then lost nearly three-quarters of that share in May. Track citation trends over several months before reallocating budget.
• Copy the quiet gainers: keep public GitHub repos and documentation current if you're in software, and actively manage Trustpilot reviews and your LinkedIn presence. All three added share while bigger names fell.
• Reddit has now grown two months straight (3.21% in March to 6.11% in May). That's a trend, not noise. If you haven't built a community strategy yet, this is the signal to start.

How we collect this data

We collect millions of prompt responses, citations, and click data from the actual user interfaces of major AI platforms: over 26 billion data points and growing. This gives us one of the largest datasets on how AI search engines cite sources and recommend brands.

Real UI monitoring

Data straight from the interfaces of ChatGPT, Gemini, Perplexity, Claude, AI Overviews, and more.

26B+ data points

Over 26 billion analyzed citations, prompts, and responses, one of the largest AI search datasets available.

Continuously updated

Refreshed constantly so the trends you see reflect the latest behavior of AI search engines.

Aggregated & public

Published freely for the GEO community, based on aggregated, non-identifiable trends.