A quarter-to-quarter league table of the most-cited domains does not exist in public. The repeated series that does exist is one domain on one engine. Promptwatch's ChatGPT panel puts reddit.com at 6.11% of citations in May 2026, 3.71% across the first twenty-seven days of June, 3.83% on average from 18 July to 7 August, and 0.52% on average from 14 to 17 August. Promptwatch calls that last step provisional. Otterly's September read says the ChatGPT loss stuck. Ahrefs, on 2 September, still has Reddit first, at 16.8% of a top-source pool. Those are not the same denominator, and they are not averaged here.
- The drop is stepwise, and the last step is flagged by the people who measured it. Promptwatch does not rule out a collection problem. The relative drop from the July-to-early-August average is 86.4%.
- Google's surfaces did not copy ChatGPT's loss. In Otterly's September table the pooled Reddit share barely moved, 1.761% to 1.714%, because AI Overviews and AI Mode still cite it.
- 16.8% and 0.52% are not a fight about the facts. One divides by the top-source pool. The other divides by all citations. Averaging them produces a number nobody published.
- google.com does not have a clean quarterly series. A Japan rank change, a wrapper URL, and a one-week snapshot are three different facts.
- Cairrot's index was published on 14 August 2026, the week of the Promptwatch break, so its three-month window may mix both sides of the drop. It is reported as a run rate versus a citation rate, not as a quarter.
The quarterly table that does not exist
The honest shape of this page is a gap with one solid series inside it. No opened source reprints the top 50, on a frozen prompt set, for two consecutive quarters, for even one engine. Monthly arrows on a vendor page are not that table. A 90-day toggle that does not print the earlier values is not that table. Early-October snapshots from other trackers are levels. They are not deltas, and they are left out so they cannot be mistaken for one.
What would count is dull. Same prompts, same engine, same denominator, two dates, the domains written down. Until that file exists, "the list changed" has to be said domain by domain. The levels, as opposed to the changes, are on the ChatGPT list and the hub.
Reddit on ChatGPT, one tracker
Promptwatch watches ChatGPT Search as a share of all citations. That is why these percentages are small next to a mention-share league table. Partial The vendor says the August break should be treated as provisional.
The path is two drops, not a fade. May to June is about a 40% relative decline, from 6.11% to 3.71%. The rate then sat in the high 3s. On 8 August it had already slipped from the high 3s into the mid 2s. On 14 August it went under 1%, and the 14 to 17 August average is 0.52%. The same day as the earlier slip, 8 August, site: queries jumped from 0.37% to 16.8% of fan-out queries, and searches per response rose from about 1.08 to 1.83. Reddit moved before the line people quote. The fan-out change is a clue, not a cause the tracker proved.
Two other Promptwatch series move on the same date. Social posts' share of classified ChatGPT citations fell from 4.4% to under 1% after 14 August. Domains at DR 91 to 100 fell from about 7% of ChatGPT citations in the first week of August to about 3% from 14 August on, and the lost share went into DR 46 to 75. Those are the same window as the Reddit break. They are not independent confirmation from a second company.
This is not Reddit's first ChatGPT drop in the public record. Profound's 10 November 2025 post, produced with Reddit, says a September volatility event took ChatGPT's Reddit share from about 7% to about 1%, after which it rebounded to about 3% and stayed at rank 2 behind Wikipedia. Treat the framing as vendor-aligned. The point for this page is narrower. A sharp ChatGPT drop has happened before, and it was not permanent that time. The 2026 break is not yet a finished story.
What did not follow it down
Otterly's September 2026 update is a different panel. ChatGPT cited Reddit for 3.765% of citations through July and 0.227% in September, which Otterly calls a 94% fall against July. Across the engines Otterly tracks, Reddit's pooled share moved from 1.761% in August to 1.714% in September. The pool barely moved because Google AI Overviews and AI Mode still cite Reddit, at about 5.1% and 4.5% of their September citations in that write-up. Copilot and Claude showed no Reddit citations in that table. YouTube, in the same social table, went from 2.189% to 1.842%.
Promptwatch's own Google windows, which are shares of all citations and not mention shares, move less than ChatGPT and more than a rounding error. From 1 to 7 July versus 11 to 17 August, Reddit on AI Overviews went from 2.37% to 2.10%. On AI Mode it went from 2.22% to 1.54%. An 11% relative dip and a 30% relative dip are not an 86% collapse. The engine list for those surfaces is AI Mode and the community page is community domains.
Ahrefs is the figure that makes dashboards look like they disagree. The US ChatGPT page, updated 2 September 2026, still ranks www.reddit.com first, at 16.8% of the top-source pool, with 810,887 pages cited. Mention share there is a domain's citations divided by the summed citations of the top sources. A 16.8% share of that subtotal can coexist with a sub-1% share of all citations if the subtotal is a thin slice of all citations, or if the underlying days are not the post-14-August days. Ahrefs does not print the window inside September. The page is dated 2 September, which is after Promptwatch's break and before Otterly's September average. Do not average 16.8 with 0.52. Do not call either one wrong on the strength of the other. Call them different fractions.
Cairrot, published 14 August 2026, is useful because it prints both rates for the same ChatGPT file. Reddit appeared on 7.8% of runs, 2,646 of 34,023, and accounted for 1.34% of citations, 3,322 of 248,168. A domain can be present in the answer more often than it is present in the footnote list. The publication date sits on the break, so the three-month window may include both regimes. Partial
Other moves that are not a re-rank
LinkedIn is a single-domain rank panel, not a new top 50. Profound, 9 March 2026, says LinkedIn's rank on ChatGPT moved from about 11 in November 2025 to about 5 by mid-February 2026, and that its citation frequency more than doubled. On professional queries, across six models and 1.4 million citations, LinkedIn became the number one domain. On-platform posts, articles, and newsletters rose from about 27% to about 35% of LinkedIn's citations inside ChatGPT. That is one site, on one kind of question. It is not a market re-rank.
Japan is two facts, and they should not be merged. On Ahrefs' September 2026 Japan page, the combined five-engine ranking is a merge of ChatGPT, AI Mode, AI Overviews, Perplexity, and Copilot. Wikipedia is first. google.com is second. YouTube fell from first to fifth. That merge is not an AI Overview ranking and not a ChatGPT ranking. Separately, the Japan ChatGPT list had Reddit first in June, and by September Reddit had left the top 10 and Kotobank was first. No percentages for that ChatGPT move were in the extract. The US September list still has Reddit first. Country panels moved in different directions in the same season.
Google citing itself is the series people expect and the series that is missing. Evertune, 23 September 2026, tracked about 180,000 AI Mode responses from 11 August to 3 September. By early September, direct citation URLs were near zero. Of the 3.8 sources that remained, 3.5 were google.com/goto redirects, which Google began wrapping around results in late August. Gemini's sources per response fell about 30%, and AI Overviews about 15%. Evertune says the decline started three weeks before Google's public bug explanation. This is a change in how links are wrapped and how many are shown. It is not a measured rise in citations to Google's own articles. The AI Mode list carries the level of google.com before that step. It should not be read as the level after it.
YouTube has its own September step, on Otterly, inside AI Mode: 13.521% of citations on 1 September to 3.877% on 20 September. The Ahrefs pages dated 2 September sit before that step. The video page keeps the levels. This page only marks the date, so the two are not averaged.
The one repeated page set, rather than a domain share, is Green Flag's finance panel. Of 215 tracked pages, half had zero ChatGPT citations by September 2026, and the group's citations fell from 23,251 to 3,271. Wikipedia and Reddit left that vertical's top 500. Banks and regulators came in. It is one vertical, anchored on seven finance domains. It is also the closest thing in public to a quarter-scale before and after on the same URLs. Duration, as a median across engines rather than a vertical, is Profound's 11-day half-life, discussed on the page list. The half-life study on this site is still a protocol: AI citation half-life.
What this does not prove
Open question A four-day average that the tracker calls provisional is not a new permanent rank. A pooled share that barely moved is not evidence that every engine held still. A Japan merge is not a US trend. A google.com/goto wrapper is not Google content winning the citation. And a finance panel in which half the tracked pages went to zero does not say the whole ChatGPT corpus turned over. It says one vertical's head did.
How to use it
When a dashboard says Reddit collapsed, or says Reddit still leads, ask three questions before you rewrite a plan. Which engine. Which dates. Which denominator. Re-pull the list on a fixed prompt set if the decision is expensive. Do not refresh a slide by averaging May's 6.11% with September's 0.227% with Ahrefs' 16.8%. The average is not a measurement.
If you need the list to be comparable next quarter, the missing object is the frozen query set. That is what the concordance protocol is for. It does not have a first quarter yet.
Reddit's share of ChatGPT citations went from 6.11% in May 2026 to a provisional 0.52% in mid-August. Ahrefs still had it first on 2 September, at 16.8% of a different pool. Do not average them.
Share on XVerification status
Promptwatch's ChatGPT series, Otterly's September update, Ahrefs' US and Japan pages, Profound's two rank notes, Evertune's AI Mode log, Cairrot, and Green Flag were the sources. No quarterly top 50 was constructed by subtracting one vendor's list from another's.
Namdev, R. (2026). How the most-cited domain list changes from quarter to quarter (v1). Retrieved from https://ritiknamdev.com/blog/most-cited-domains-quarterly-change Published under CC BY 4.0 — reuse freely with attribution.
The level each engine is at, rather than the change, is on the engine lists. Reddit's role on one engine is on community domains.