Only 81 of 1,843 Domains Are Cited
by All 4 Major AI Engines

01Study Overview

As our previous report established, the overlap rate of domains cited by the four major AI search engines is approximately 10%. This raises a critical question: what domains constitute that narrow overlap — the sources trusted by every engine?

In this report, we present the TOP10 domains cited by all four AI engines, extracted from 9,891 domain citation records. These represent the citation sources that are effective across all engines, making them highly actionable for Generative Engine Optimization (GEO) strategy prioritization.

02TOP10 Domains Cited by All 4 Engines

The following table ranks the domains cited by all four engines by total citation count.

#1: my-best.com (MyBest)

A product comparison media site claims the top position. MyBest publishes comparison articles across a broad range of categories — consumer electronics, cosmetics, financial products, and food — and all four AI engines treat it as a trusted comparative information source. For businesses operating in the Japanese market, securing a listing on MyBest constitutes a GEO strategy that is effective across all engines simultaneously.

#2: youtube.com (YouTube)

Video content on YouTube is cited by all four engines. However, it is important to note that AI engines do not process the visual content of videos. Instead, they extract information from titles, descriptions, and transcript (subtitle) text. Even if a brand name is mentioned verbally within a video, AI engines cannot recognize it unless subtitles are enabled (see our detailed guide on LLMO optimization strategies).

#3: prtimes.jp (PR TIMES)

Japan's largest press release distribution platform ranks third. Our data indicate that distributing press releases through PR TIMES is an effective means of establishing brand presence across all AI engines. It should be noted, however, that the citation efficacy of press releases is contingent upon the domain authority of the distribution platform. PR TIMES is cited precisely because of its high domain authority, underscoring the importance of platform selection.

03Domain Type Analysis

Classifying the 81 universally cited domains by type reveals the following structure.

These findings strongly suggest that SEO optimization of a company's own website alone is insufficient for effective GEO strategy. Even if a brand's own domain achieves high search rankings, it will be cited by only a subset of engines (the cross-engine citation overlap rate is approximately 10%). In contrast, presence on comparison media and major platforms creates the potential for citation by all engines.

04Actionable Recommendations for Businesses

Based on the findings of this study, the following GEO strategies are prioritized by their cross-engine effectiveness.

Priority 1: Listing on Comparison Media Sites

Comparison media account for 40% of the TOP10. Securing listings on comparison sites relevant to your industry — such as MyBest (consumer products), Coeteco (education), BOXIL and IT Trend (SaaS), and ASPIC (cloud services) — should be the highest-priority initiative. While some comparison media require paid listings, many also accept free submission requests. For further guidance, see our detailed article on AI search optimization for businesses.

Priority 2: Brand Mentions on YouTube

Establish a presence where your brand is mentioned on YouTube. In addition to publishing content on your own channel, being featured in review videos and comparison videos by third parties is also effective. It is critical that the brand name appears in transcripts (subtitles); manual subtitle configuration is recommended.

Priority 3: Press Release Distribution via PR TIMES

Distribute press releases on a regular basis through PR TIMES, covering new products, updates, awards, and research reports. Our data confirm that AI engines cite PR TIMES as a trusted information source.

Priority 4: Expert Content on note.com

note.com is among the universally cited domains. Publishing expert articles that include industry insights and case studies on a regular basis increases the likelihood of being cited by AI engines.

05Methodology

The data presented in this report are drawn from the same dataset described in our previous publication, "Cross-Citation Overlap Across 4 AI Search Engines: A Proprietary Study of ~10,000 Records". For detailed methodology, please refer to that report.