Microchip maker NVIDIA more than doubled its revenue in the second quarter thanks to just a few “whales” that account for almost half of the company’s total revenue. Fortune writes about it.

The four customers, whose names were not disclosed, directly purchased goods and services for 46% of NVIDIA’s $30 billion in revenue. This amounts to approximately US$13.8 billion, according to the company’s quarterly report.

NVIDIA’s business ties with these customers are so significant that the company notes them in a section of its quarterly reports called “revenue concentration” dedicated to cluster risks.

The company’s most popular products are AI chips such as H200. They are needed to train large language models. They are also used to provide inference, the process that ChatGPT or Sora uses to generate answers to text queries.

This reliance on a few large customers also underscores market concerns about how sustainable such sharp growth in just one line of business can be. Some investors, such as Elliott Management and Citadel, have expressed skepticism about how long this can last.