ChatGPT responses referenced about 20% fewer websites following the early-March transition to GPT-5.3 Instant, according to analysis by French SEO consultancy Resoneo.
This decline was derived from data collected by Meteoria, an AI visibility-tracking platform that monitored 400 prompts daily for 14 weeks, totaling 27,000 responses. The findings suggest that fewer unique domains are cited per response, impacting online visibility for websites.
The analysis revealed that the average number of unique domains mentioned in each response dropped from 19 before the transition to 15 afterward. Similarly, the average number of unique URLs per response fell from 24 to 19, while the URLs-per-domain ratio remained constant at 1 throughout the monitoring period.
This data indicates that ChatGPT is exploring less diversity in sites per response, while still delving effectively into those it does reference. The reduction leads to fewer domains sharing the same citation surface, meaning that the remaining cited sites take a larger share of the response.
Jérôme Salomon’s independent log analysis at Oncrawl corroborates Resoneo’s findings, illustrating a reduction in crawl volume. His data shows some pages are no longer being crawled, and the frequency at which remaining pages are visited has also decreased.
Resoneo connects these trends to the influence of GPT-5.3 Instant, which reportedly triggers fewer web searches and citations compared to prior models. Oncrawl’s log data reflects this lesser crawl pattern during the same period.
An SE Ranking analysis of 129,000 domains indicated that the number of referring domains is a strong predictor of the likelihood of ChatGPT citations, particularly at a threshold of 32,000 referring domains. Additionally, a Search Atlas report noted a low overlap between Google rankings and ChatGPT citations, with median domain overlap around 10-15%.
The 20% decline in cited domains per ChatGPT response suggests fewer websites are competing for visibility, even as the total citation surface has diminished. However, the sites that remain continue to maintain their depth of engagement.
Resoneo advises businesses monitoring referral traffic from ChatGPT to specifically review their analytics from the early-March model transition.
The analysis points to future developments, noting that GPT-5.4 Thinking appears to reintroduce search fan-outs and utilizes site operators to focus on trusted domains, though these dynamics were not part of the quantitative dataset covering GPT-5.3 Instant and earlier versions. Uncertainty remains about whether the citation surface will continue to narrow or expand with upcoming models.
