68% of AI Citations Come From Just 15 Websites
Just 15 domains absorb 68% of all AI citation share. Most SMBs are not on any of them.
Founder, Vyzz
The Citation Concentration Map Just Landed
A communications agency named 5W published an index on May 1 that changes how you should think about visibility in ChatGPT, Claude, Perplexity, Gemini, and Google AI Overviews. The index synthesized more than 680 million individual citations across those five engines, drawn from six of the largest published studies conducted between August 2024 and April 2026. The headline is stark: the top 15 domains absorb 68% of all AI citation share.
If you run a regional medspa, a dental practice, an HVAC operation, or a small in-home care agency, here is what the index tells you. When an AI engine answers a customer's question, it cites sources. Most of those citations come from a tiny list. Reddit sits at number one across every engine, accounting for roughly 40% of all citations. Wikipedia dominates ChatGPT specifically, appearing in 26 to 48% of its top-10 citation share alone. Everything else splits the remaining 32% of the supply.
The concentration finding is significantly hotter than what organic search produced. In the Google era, PageRank distributed ranking power across millions of domains. AI citations are running through about 50 gateways, and 15 of them do most of the work. The operator-side question is whether your business is referenced anywhere in those top 15. For most service businesses we audit, the answer is no.
What You Actually Need to Know
The 5W index is big-picture research. What it reveals for your business is actionable in one morning.
A Birdeye study cited in the 5W research found that 80% of brands appear in AI citations at least once. That sounds good until you read the next number: only 15% of brands secure the top citation position using their own domain. Most top slots show up on Reddit threads, Wikipedia entries, or industry publications. The remaining 20% of brands do not appear in AI citations at all. If your business falls into that 20%, you have zero AI visibility to AI answer engines today, no matter how polished your website is.
The operator job, then, is twofold. First, run a self-check. Second, figure out which of the top 15 or top 50 gateways your business has any organic reason to appear on. A dental practice probably has no reason on Reddit's r/technology. It has every reason on r/Dentistry or in a dental industry publication. An HVAC contractor can seed mentions in HVAC forums or local service directories that AI engines index. An in-home care agency can get mentioned in elder care publications or local resource guides. The work is identifying which gateway your customers already research in, and making sure you're credibly mentioned there. Blanket-spamming Reddit fails badly and harms the brand.
How to Run Your Own Audit Right Now
What are the top sources that AI engines cite?
Reddit ranks number one across every major AI engine, accounting for roughly 40% of all citations. Wikipedia dominates ChatGPT specifically, appearing in 26 to 48% of its top-10 citations. The top 15 domains combined absorb 68% of all AI citation share.
What does this mean if my business isn't on any of those top sources?
If your business doesn't appear on Reddit, Wikipedia, industry publications, or other high-citation-share sources, you're competing for the remaining 32% of citation share. Most of that long tail goes to the largest, most-established players. Regional SMBs need a presence on at least one gateway source to be competitive.
How do I know if my business shows up in AI search results?
Type your business name and your top three customer questions into ChatGPT and Perplexity. Notice which sources the AI engines cite when they answer. Does your business appear anywhere in those sources? If you're absent from every cite, you are functionally invisible to AI engines. Run this self-check before lunch today.
The Sourced Numbers
The 5W index is the largest cross-platform sample of AI citations published to date. Here is what it shows.
680 million citations consolidated across ChatGPT, Google AI Overviews, Perplexity, Gemini, and Claude. That is the sample size. Big enough to see patterns. Patterns are what operators need to understand where to invest visibility effort.
Reddit approximately 40% across every engine. Reddit is now the single largest input to AI answer engines. If your business has never been mentioned in a Reddit thread that someone would actually find when researching your service, that is the most concentrated visibility gap you can address this quarter. Reddit's dominance in AI citations reflects the platform's role as a source of authentic user experience across verticals.
Wikipedia 26 to 48% of ChatGPT citations. Wikipedia dominates ChatGPT specifically. For service businesses, this metric reflects how category-level Wikipedia entries route queries about your service. Your specific business gets cited only when it shows up alongside the category entry through other channels like industry publications or local directories.
Top 15 domains carry 68% of citation share. The supply is significantly more concentrated than Google's ever was. The implication is that the long tail of trying to rank your own pages for everything yields diminishing returns in the AI era. Showing up on a small number of high-share gateway sources matters disproportionately. This is the core finding operators need to act on.
80% of brands cited at least once; 15% in top position from own domain. Most brands appear in AI citations somewhere. The harder question is position. A brand's own domain holds the top citation slot only 15% of the time. Most top slots go to Reddit, Wikipedia, or industry publications. The operator job is making sure those gateway sources also have a credible mention of you.
Your Monday Morning Action
The most useful thing you can do this morning is run the audit yourself. There's no permission to ask for and no tool to install.
Open ChatGPT or Perplexity. Type your business name and your top three customer questions. The ones you hear every single week. "What is a dental implant?" "How much does a medspa facial cost?" "Can HVAC companies repair my heat pump in January?" Run each one and look at the sources the AI engine cites when it answers.
Notice three things in each answer. First, whether your business name appears in the cited sources at all. Second, whether your own domain shows up. Third, the presence of any third-party publication that mentions your business. If the answer to all three is no, you are functionally invisible to AI answer engines today. That clarity is what the concentration problem looks like in human terms.
If the answer is yes to at least one, notice which source cited you. Is it a Reddit thread? A Wikipedia entry? An industry publication? A directory listing? That tells you which gateway is already working for you. The next move is seeding the same mention on the other gateways your customers actually research in.
The 5W index is quantifying something operators already sense: visibility in AI answer engines depends on third-party mentions alongside your website. The gateway concentration map is real. Most SMBs are not on the map at all. Your competitor might be. Check.
Sources
5W AI Platform Citation Source Index 2026
Frequently asked questions
- What are the top sources that AI engines cite?
- Reddit ranks number one across every major AI engine, accounting for roughly 40% of all citations. Wikipedia dominates ChatGPT specifically, appearing in 26 to 48% of its top-10 citations. The top 15 domains combined absorb 68% of all AI citation share.
- What does this mean if my business isn't on any of those top sources?
- If your business doesn't appear on Reddit, Wikipedia, industry publications, or other high-citation-share sources, you're competing for the remaining 32% of citation share. Most of that long tail goes to the largest, most-established players. Regional SMBs need a presence on at least one gateway source to be competitive.
- How do I know if my business shows up in AI search results?
- Type your business name and your top three customer questions into ChatGPT and Perplexity. Notice whether the sources cited mention you anywhere. Absence across all sources signals functional invisibility to AI engines.