Read the email to Satya Nadella and Bill Gates that shows Microsoft's CTO was 'very worried' about Google's AI progress in 2019

• Microsoft's OpenAI investment may have been prompted by concerns over Google's AI progress.
• In a 2019 email, a Microsoft exec said he was "very, very worried" about Google's AI capabilities.

In 2019, Microsoft became "very, very worried" about Google's capabilities in artificial intelligence, newly unearthed emails show, and that may have been what spurred it to invest in OpenAI.

In one lengthy email, Microsoft's chief technology officer, Kevin Scott, told CEO Satya Nadella and Bill Gates that Google's AI-powered "auto-complete in Gmail" was "getting scarily good."

He added that Microsoft was "multiple years behind the competition in terms of ML scale," referring to machine learning.

The emails, which had the subject line "Thoughts on OpenAI," were made public on Tuesday as part of the Department of Justice's antitrust case against Google. A large section of Scott's email was redacted.

In response, Nadella said the email highlighted "why I want us to do this" and copied Microsoft's chief financial officer, Amy Hood, into the chain.

Microsoft didn't immediately respond to a request for comment from Business Insider, made outside normal working hours.

In 2019, Microsoft made an initial $1 billion investment into its now multi-billion-dollar partnership with OpenAI.

Microsoft has since benefited from its well-timed investment.

After public and investor interest in AI surged post-ChatGPT, Microsoft was able to move quickly, incorporating OpenAI's buzzy tech into existing products such as Bing and Microsoft 365.

The speed at which Microsoft released AI products even left some wondering whether its arch-rival Google had been left behind.

Google, a pioneer of AI technology, has been trying to counter the narrative that it has fallen behind Microsoft ever since. The company released several products to compete with OpenAI's releases, including Bard, an AI-powered chatbot, and an AI model named Gemini.

The 2019 email exchanges also show how Microsoft was keeping tabs on its rivals, with Scott saying the scale of OpenAI, DeepMind, and Google Brain's AI ambitions were "interesting." Among some of the mentions of what its competitors were doing, Scott mentioned Google's data-center designs and distributed-systems architecture.

Discussing Microsoft's AI talent, Scott said it had "very smart" people with machine-learning expertise in its Bing, vision, and speech teams. He added that the teams faced constraints on scaling up their ambitions, which suggests why Microsoft saw potential in partnering with OpenAI to bring its AI aspirations to fruition.

Scott added that when Open AI, Deep Mind, and Google Brain were competing to see who could achieve "the most impressive game-playing stunt," he was "highly dismissive of their efforts," but "that was a mistake."

Read the unredacted portions of the emails below. RL refers to reinforcement learning, NLP is natural language processing, and BERT is bidirectional encoder representations from transformers.