Every link inside a Google AI Overview carries a text fragment, `#:~:text=`, appended so the browser can jump to the sentence being quoted. Search Engine Land analyst Alex Galinos built a custom GA4 dimension to catch that fragment and left it running from September 2025 to June 2026: 51,200 AI Overview citation events across 1,661 cited snippets, cross-checked against Ahrefs. Nine months of that data produce two numbers. The first is volume. AI Overviews drove 7.53% of organic sessions over the period, spiked to 16% to 17% of organic sessions in February and March 2026, then fell to 2% to 4% of organic sessions by the article's publication on August 18, 2026. The second is where that traffic landed in the report. Every month, between 16.8% and 29.3% of AI Overview-sourced sessions were recorded in GA4 as Direct-channel sessions, 22.4% on average, with the low of 16.8% in April 2026 and the high of 29.3% in May 2026. An AI Overview link sends no referrer, so GA4 files it the way it files a bookmark or a typed URL.
Credibility: MEDIUM. Single-source proprietary study. The methodology (a GA4 custom dimension, cross-checked against Ahrefs) is disclosed and checkable inside the article itself, but no second outlet has independently reproduced the numbers, and Search Engine Land is owned by Semrush, an SEO-tooling vendor with a mild incentive to frame AI-search measurement as a solvable tooling problem.
Fact bullets:
- 51,200 AI Overview citation events tracked across 1,661 cited snippets, September 2025 to June 2026 (9 months).
- AI Overviews drove 7.53% of organic sessions overall; volatility ranged from a 16% to 17% peak (February and March 2026) to 2% to 4% by publication (August 18, 2026).
- 22.4% of AI Overview-sourced sessions were misattributed to the Direct channel in GA4 on average, ranging from 16.8% (April 2026, best month) to 29.3% (May 2026, worst month).
- Tracking method: a custom GA4 dimension capturing the `#:~:text=` URL fragment Google appends to AI Overview citation links, cross-verified against Ahrefs.
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If you have ever walked a client or your leadership through a Direct-traffic increase, part of what you were showing them is Google failing to name its own referral.
Two numbers in this study decide whether the third one matters to you. The gap is real, and in percentage terms it is large: in the worst month, 29.3% of the traffic AI Overviews sent arrived labelled as Direct. But that is 29.3% of a channel worth 7.53% of organic sessions across the period, and 2% to 4% of organic sessions by August, so on current volumes the mislabelled slice is small. The window where it was not small is February to June 2026, when AI Overviews were running at 16% to 17% of organic sessions. If a client's Direct-channel sessions grew materially in those months and someone credited a brand campaign or a PR push, some of that lift may be Overview clicks GA4 could not label, which overstates the result to whoever is reading the report. The Direct line is still worth reporting. It is missing one thing: a way to tell an AI Overview click apart from a bookmark.
Recommended actions:
1. Ask your web or analytics team to add a GA4 custom dimension keyed to the `#:~:text=` URL fragment, so AI Overview sessions stop landing in the Direct bucket from here on.
2. Re-pull each client's Direct-channel trend for February to June 2026 and read it against this study's 16% to 17% AI Overview peak before crediting any spike to a brand or PR push.
3. Write the decision rationale into the reporting notes whenever Direct-channel growth goes to a client or to leadership this quarter, including whether AI Overview misattribution was checked.
Search Engine Land: "What 9 months of AI Overview data and 51,000+ tracked events reveal" by Alex Galinos, August 18, 2026, https://searchengineland.com/ai-overview-data-51000-tracked-events-485080