OpenAI Buys Startup Neptune for AI Training Tool
By Reuters | 03 Dec, 2025

The Microsoft-backed company is beefing up its AI capabilities in preparation for a 2026 IPO that may value it at $1 trillion.

OpenAI has agreed to acquire Neptune, a startup that provides tools that help companies track their AI model training, the ChatGPT maker said on Wednesday. 

While OpenAI did not disclose the financial terms of the deal, The Information reported that OpenAI is paying less than $400 million in stock, citing people with knowledge of the deal.

OpenAI did not immediately respond to a Reuters request for confirmation on the deal value. 

The Sam Altman-led firm is already a Neptune customer, using Neptune's tracker to monitor and debug training of its GPT large language models. Some of Neptune's other clients include Samsung, Roche and HP. 

Initially an internal tool at Deepsense, Neptune was spun off as an independent startup in 2018. The company has secured more than $18 million in funding, according to its website. 

OpenAI reached a valuation of $500 billion in October, following a deal in which current and former employees sold roughly $6.6 billion worth of shares.

Microsoft-backed OpenAI is preparing for what could rank among the largest IPO ever, with a potential valuation of up to $1 trillion. The firm is laying the groundwork to go public and may file with securities regulators as early as the second half of 2026, Reuters has reported.

However, OpenAI's chief financial officer, Sarah Friar, said later in November that a listing is not in the startup's near-term plans.

OpenAI has taken a stake in Thrive Holdings as part of a partnership to embed artificial intelligence into traditional industries such as accounting and IT services.

(Reporting by Deborah Sophia in Bengaluru and Juby Babu in Mexico City; Editing by Alan Barona)