Microsoft has built a big business selling artificial intelligence models to Chinese companies despite the growing rivalry between the U.S. and China over the technology.

Social media and AI giant ByteDance has generally been Microsoft’s biggest AI customer in recent years, largely using OpenAI models, according to people familiar with the matter. The Beijing-based company is on track to spend more than $1 billion a year on Microsoft AI and cloud services, said some of the people, who requested anonymity to discuss a private matter.

Other Chinese tech firms, such as Ant Group, Meituan and Tencent Holdings are also significant spenders on AI models via Microsoft’s Azure cloud service, people familiar with the business said.