Vercel Index: Open-Weight Models Surpass 70% of Tokens as Switching Rates Hit Record High

According to a report by German tech outlet heise online, Vercel's AI Gateway Production Index reveals that as of September 2026, 71.5% of all tokens processed through its gateway came from open-weight models. This marks the first time this category has exceeded proprietary frontier models in token share on the Vercel platform. Another major aggregator, OpenRouter, had already crossed this threshold in June.

In terms of spending, open-weight models accounted for 23% of estimated total expenditures on the Vercel gateway. Notably, this share was only about 5% in June, representing a more than fourfold increase within three months. Since December 2025, spending on open-weight models has grown by over 70 times, while spending on proprietary frontier models increased by 'only' ten times during the same period.

The data also highlights significant shifts in market structure. Anthropic's share of gateway spending fell below 50% for the first time in a long period, dropping from 63.7% in the previous month to 43.9%. However, token usage does not directly equate to spending due to vast price differences. For instance, DeepSeek-V4.1-Flash processed nearly half of all open-weight tokens in September but accounted for only 2.6% of open-weight spending, as its token price was roughly one-fifth of the average.

A striking trend is the record-high frequency of 'model switching.' In September, nearly half (48%) of teams changed their most-used model, and almost one-third (28.6%) switched their most-used provider. Both metrics have risen for the fifth consecutive month. Vercel interprets this as a sign that AI models are increasingly becoming interchangeable components. Furthermore, 68% of teams that increased spending on open-weight models also raised their spending on closed-weight models, indicating that hybrid strategies remain dominant.