MOUNTAIN VIEW, CALIF. — OpenAI, the artificial intelligence (AI) giant behind ChatGPT and the $500 billion Stargate Project, has signed a lease with KKR Real Estate Finance Trust Inc. (NYSE: KREF) and TMG Partners to fully occupy 350-380 Ellis, a Class A office campus in the Silicon Valley city of Mountain View.
The five-building asset offers 450,000 square feet of office space with move-in ready finishes, indoor and outdoor work environments, meeting/conference rooms, rooftop decks, an executive briefing center, kitchen/break areas on each floor and collaborative space. The campus also features a full-service gastropub restaurant and cafeteria, multi-story parking structure, a tennis court and a sand volleyball court.
The property is owned by KREF and capital accounts advised by the REIT’s parent company, KKR & Co. Inc. (NYSE: KKR). In 2024, TMG was selected to reposition 350-380 Ellis into a future-ready office campus.
Jon Mackey, Mike Saign and Phil Mahoney of Newmark represented the landlord in the lease negotiations, while Mike Ino, Jon Moeller, Dan Johnson, Rich Duff and Bridget Fahey of JLL represented OpenAI.
Founded in 2015, OpenAI has a current market valuation of $840 billion based on its latest fundraising campaign that closed in late February. Sam Altman is the CEO of the San Francisco-based company, which comprises a nonprofit division (OpenAI Foundation) and a for-profit division structured as a public benefit corporation (OpenAI Group PBC). OpenAI Foundation currently has a 26 percent equity stake in OpenAI Group following the company’s recapitalization.
KKR Real Estate Finance Trust maintains more than $86 billion in assets under management as of Dec. 31, 2025. The REIT’s stock price closed on Monday, March 23 at $6.41 per share, down from $11.41 a year ago, a 43.8 percent decline.
Founded in 1984, TMG Partners is based in San Francisco and maintains a 33 million-square-foot portfolio in the Bay Area valued at $6.8 billion. The portfolio includes mixed-use developments, office, retail, residential and industrial properties.
— Amy Works and John Nelson