Our AI measurement system caught dramatic shifts in how OpenAI's models remember Microsoft's Bing—weeks before partnership tensions became public.

OpenAI's models cited Bing 88% of the time in July. By November: 68%. Meanwhile, Claude increased Bing citations, and smaller models showed stable patterns. The data shows model-specific changes, not market-wide shifts.
In late October 2025, our AI memory tracking system detected something unusual: Microsoft Bing's visibility in OpenAI models had dropped 23 percentage pointssince July, while simultaneously increasing 12% in Anthropic's Claude models.
This wasn't a gradual decline. It was a sharp, systematic shift that suggested something had changed in how OpenAI was training or weighting Microsoft-related content.
Three weeks later, Bloomberg and other outlets began reporting on partnership tensions between Microsoft and OpenAI. But we had already seen the data.
When we analyzed the data more deeply, we found:
The data shows that different AI models remember brands differently, and those patterns can change over time. For OpenAI models, Bing citations decreased. For Claude models, they increased. For smaller models and European models, patterns remained stable.
This isn't about "bias" or "disrespect." It's about measurement. The data shows that for European users or those using smaller models, Bing remained a strong source. For OpenAI model users, the pattern shifted. We measure what models remember—by category, by model, over time.
"When AI models change how they remember your brand, it's not always because your brand changed. Sometimes it's because the model's training changed."
This isn't just about Microsoft and OpenAI. We've detected similar patterns across 179 brands:
Different models remember brands differently. Some models show strong patterns for certain categories. Others show different patterns. We measure it all—so you can see what's happening and decide what matters.
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