Branch launches ChatGPT Ads attribution amid shifting AI market shares

The AI advertising and search landscape is undergoing significant shifts in market share and measurement capabilities. Branch has announced new support for ChatGPT Ads attribution, allowing advertisers to track customer activity—including app installs, web visits, and conversions—across mobile, web, and desktop platforms. This tool enables marketers to connect paid ChatGPT campaigns with organic AI traffic and other acquisition channels.

Market data indicates a changing competitive environment for AI assistants. According to Comscore, ChatGPT’s share of US AI prompt volume fell from 70% in January 2026 to 50% by June 2026, as Google’s Gemini rose to 30% and Anthropic’s Claude reached 11%.

In terms of web referral traffic, BrightEdge reports that ChatGPT dominated the sector in August, accounting for 95.1% of all traffic sent to websites from AI chatbots. This represents a 101% increase in ChatGPT’s referral traffic between January and August. In comparison, Gemini accounted for 2.4%, Perplexity for 1.1%, and Claude for 0.8% of the referral traffic during the same period.