By Arsheeya Bajwa and Krystal Hu

(Reuters) -Amazon.com pumped another $4 billion into OpenAI competitor Anthropic, as the e-commerce giant goes up against Big Tech rivals in a race to capitalize on generative artificial intelligence technology.

This doubles Amazon's investment in the firm known for its GenAI chatbot Claude, but it remains a minority investor, the startup said on Friday. Similar to Amazon's previous $4 billion investment, it comes in the form of convertible notes and comes in phases, first at $1.3 billion.

Anthropic is also in talks with additional investors to raise more capital on the back of Amazon backing, sources added, who requested anonymity for discussing private matters. Anthropic declined to comment.

Amazon, which has gradually established itself as Anthropic's primary cloud partner, is fiercely competing with Microsoft and Alphabet's Google to offer AI-powered tools for its cloud customers. AWS is bringing significant revenue to Anthropic as a major distributor of its latest models.

"The investment in Anthropic is essential for Amazon to stay in a leadership position in AI," said D.A. Davidson analyst Gil Luria.

The e-commerce company's increased investment in Anthropic underscores the billions of dollars funneled into AI startups over the past year, as investors look to cash in on a boom in the technology, which became popular with the launch of OpenAI's ChatGPT in late 2022.

Microsoft-backed OpenAI raised $6.6 billion from investors last month, which could value the company at $157 billion and cement its position as one of the most valuable private companies in the world.

Anthropic plans to train and deploy its foundational models on Amazon's Trainium and Inferentia chips. The intensive process of training AI models requires powerful processors, making securing pricey AI chips a top priority for startups.

"It (partnership) also allows Amazon to promote its AI services such as leveraging its AI chips for training and inferencing, which Anthropic is using," Luria said.

Nvidia currently dominates the market for AI processors and counts Amazon among its long list of so-called hyperscaler customers.

Still, Amazon has been working to develop its own chips through its Annapurna Labs division, which Anthropic said it was "working closely with" to aid in developing processors. Amazon has also been trying to build its own AI model code-named “Olympus,” which it hasn't released.

Anthropic, co-founded by former OpenAI executives and siblings Dario and Daniela Amodei, said last year it had secured a $500 million investment from Alphabet, which promised to invest another $1.5 billion over time.