Launching – AI Traffic Index by Industry

The AI Traffic Index tracks measured, first-party AI referral sessions by industry, updated monthly. No modelled numbers. No estimates.

LLMs have fundamentally broken the reporting paradigm for SEOs and marketers alike. It’s been a couple of years and we’ve done extensive studies on LLM referral traffic [1, 2, 3].   In that time, very little has changed to help individual marketers or SEOs to know where things stand.  

• Organic is being obfuscated and tracked as direct
• LLMs are hitting your site as assistants, training bots, search bots and actual visits
• GA4 (if firing in the browser) is essentially a guest book at a bed and breakfast fewer people are choosing to sign
• Synthetic prompt tracking is directional at best

In order to overcome some of the noise that’s in the market, we’ve created an index that tracks actual verifiable referred sessions.  I know, I know.  I just said there are so many caveats.   What we’re trying to do is reassemble a fractured view and understand broader trends.  This gives us a better way to reorient ourselves while other measurement paradigms mature.  I’m bullish on Cloudflare but that will take some time and not everyone is using it.

So in the meantime – let’s launch a public index for everyone to benefit from. Bring in the AI Traffic Index!

Five industries, to start

We’re starting with several industries that we call ‘digitally native’.  These are sites and industries that either live on the internet or are, in large part, dependent on their web performance.

• Insurance: went from near the bottom to #1. Most of the jump happened in one month.
• Finance: the early leader, and the one place Perplexity actually matters.
• SMB: the most volatile line in the Index. Wait until you see the swings.
• Legal: the only industry with a steep fall. It’s now below average.
• SaaS: the category that talks most about AI gets almost none of its traffic from it.

We’ll dig into one industry each month on LinkedIn Live. Here’s what’s under the hood:

What the Index measures

The Index measures one thing: LLM share, meaning AI-referred sessions divided by all sessions for the same industry and month.

• Source: First-party GA4 sessions from sites in Previsible’s network, grouped by industry. Want your site included? Add it to the Index.
• What counts as AI: sessions whose referrer or UTM source is chatgpt.com, perplexity.ai, gemini.google.com, claude.ai, copilot.microsoft.com, grok.com, you.com, meta.ai or x.ai. 
• Period: December 2024 to October 2026. A new edition publishes monthly. The next one is out December 1.
• What it doesn’t measure: AI Overviews, AI Mode, or any other AI result served inside Google. They pass no AI referrer.

No modelled traffic. No third-party estimates. 

What it means for marketers

1. Benchmark against your industry, not the internet. Measure your own sites against the broader market and industries to know where you stand.

2. Growth isn’t guaranteed. The all-industry average rose from 0.22% to 0.33% between October 2025 and October 2026. But the swings are large and unpredictable.

3. Optimize for ChatGPT first, but know your second. ChatGPT sends 72% to 92% of AI sessions in every industry here. The runner-up depends on the industry: Perplexity in finance and legal, Gemini in insurance, SMB and SaaS.

4. AI traffic isn’t just top-of-funnel. In all five industries, commercial or navigational pages had the highest LLM share (ie percent of traffic coming from AI referrers versus all traffic). Informational pages ranked third or lower every time. That’s a rate, not volume: informational pages may still get more AI sessions in total.

5. It’s still small but it’s also not the whole picture. The top industry gets 1.5% of its sessions from AI referrers. Organic search isn’t going anywhere yet.

What next

The AI Traffic Index publishes monthly. The next edition is out December 1, with more industries to follow. 

Want to see where your site sits against your industry? Contact us.