ByteDance Trains 10 Trillion-Parameter AI Model to Rival Anthropic's Mythos

ByteDance is pretraining a large model with up to 10 trillion parameters, a scale the Financial Times reports could put it in the same class as Anthropic's most advanced systems. The model, still in early pretraining, would be more than three times the size of Moonshot AI's Kimi K3, currently the largest Chinese model at 2.8 trillion parameters. Three people familiar with the project told the FT the model is in pretraining, a phase that typically lasts three to six months before full training a

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August 7, 20262 min

ByteDance Trains 10 Trillion-Parameter AI Model to Rival Anthropic's Mythos

Model scale comparison showing ByteDance's reported 10T-parameter target against current Chinese and US frontier models

Three people familiar with the project told the FT the model is in pretraining, a phase that typically lasts three to six months before full training and evaluation. Parameter counts are a rough measure of capacity rather than a guarantee of capability, since output quality also depends on training data and methods.

Industry estimates cited by the FT place Anthropic's Mythos 5 at roughly 8 trillion parameters and its Fable 5 at around 5 trillion. Neither Anthropic nor OpenAI discloses parameter counts for its flagship systems, which makes direct comparisons with private US models difficult. ByteDance's reported target sits close to the estimated size of Mythos.

The project sits with ByteDance's Seed research team, the roughly 2,000-person lab behind the company's frontier model work. Founder Zhang Yiming has told the team to aim for world-leading model capabilities over the long term, according to one of the sources. The source also said ByteDance has avoided distillation, training on outputs from other companies' models, for over a year.

xAI is pursuing comparable scale. Elon Musk has said the company is training Grok variants with six and ten trillion parameters on its Colossus 2 cluster.

China's largest AI model is being developed at ByteDance, and the company is publicly positioning around scale. It launched SeedRealtime, a full-duplex audio-visual LLM, in early August, and its Doubao assistant app has one of the largest user bases among Chinese AI products. A 10 trillion-parameter pretraining run, if completed, would mark a step up in the scale of Chinese frontier models.