Elon Musk’s legal team has lost key motions targeting Microsoft’s decision rights in the OpenAI lawsuit, with a federal judge granting Microsoft’s request for summary judgment on claims of tortious interference and unjust enrichment, as of May 13, 2026.
Musk’s Lawyers Lose Ground Over Microsoft’s Role in OpenAI
In a setback for Elon Musk’s legal strategy, a federal judge in the Northern District of California has ruled against his attempt to challenge Microsoft’s major decision rights in OpenAI. The decision, handed down on May 13, 2026, grants Microsoft’s motion for summary judgment on Musk’s claims of tortious interference with contract and unjust enrichment, while denying the broader motion. This outcome effectively limits Musk’s ability to use the courts to overturn Microsoft’s influence over OpenAI’s operations and strategic direction.
The ruling stems from Musk’s $134 billion lawsuit against OpenAI, Sam Altman, and Greg Brockman, alleging breach of charitable trust and other claims. Musk’s legal team sought to implicate Microsoft, which has invested billions in OpenAI’s for-profit ventures, arguing that the tech giant interfered with OpenAI’s original nonprofit mission. However, the court found insufficient evidence to support Musk’s claims against Microsoft on the specific counts advanced.
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The Legal Battle Over OpenAI’s Governance
The dispute centers on Musk’s contention that OpenAI, initially founded as a nonprofit in 2015, violated its founding principles by transitioning to a for-profit model and accepting Microsoft’s investments. Musk, a co-founder and early donor, argues that OpenAI’s leadership reneged on promises to keep the organization nonprofit and publicly beneficial.
According to court filings, Musk donated approximately $38 million to OpenAI between 2016 and 2020, including $5 million per quarter from 2016 to 2017 and $12.7 million for office space. The founding documents emphasized that OpenAI’s technology would be “owned by the foundation and used for the good of the world,” with safety as a “first class requirement.”
Microsoft’s involvement escalated in 2019, when the company invested $1 billion in OpenAI, followed by additional investments totaling over $13 billion by 2023. This financial backing enabled OpenAI to develop and commercialize advanced AI models, including ChatGPT. Musk’s lawsuit alleges that Microsoft’s influence has distorted OpenAI’s original mission, but the court has now ruled that Microsoft’s actions do not constitute tortious interference or unjust enrichment as claimed.
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Why the Ruling Matters
The judge’s decision is a significant blow to Musk’s efforts to use legal action to regain control over OpenAI. By granting summary judgment on the specific claims against Microsoft, the court has effectively shut down Musk’s attempt to challenge the tech giant’s decision-making authority within OpenAI. This ruling does not, however, resolve the broader dispute over OpenAI’s governance or Musk’s claims against Altman and Brockman, which remain pending.
Legal experts suggest that Musk’s strategy may have been flawed from the outset. By focusing on Microsoft’s decision rights, his legal team may have overreached, as the court found that Microsoft’s investments and operational involvement do not rise to the level of wrongdoing alleged. The ruling underscores the complexity of litigating disputes over corporate governance, especially when major tech players are involved.
For Musk, the setback could further complicate his efforts to position himself as a champion of nonprofit AI research. The court’s decision may also embolden Microsoft to continue its strategic partnership with OpenAI, which has become a cornerstone of the company’s AI ambitions.
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What Comes Next
The trial between Musk and Altman is ongoing, with testimony from key figures including Microsoft CEO Satya Nadella already delivered. The next phase of the lawsuit will focus on Musk’s claims against Altman and Brockman, with the outcome potentially shaping the future of OpenAI’s governance and Musk’s influence in the AI space.
As of May 13, 2026, the legal landscape remains uncertain. Musk’s legal team may appeal the summary judgment ruling, but the immediate impact is clear: Microsoft’s role in OpenAI is now legally protected from Musk’s specific claims of interference and enrichment. The broader implications for OpenAI’s mission, Microsoft’s investments, and Musk’s ambitions in AI will continue to unfold in the courtroom and beyond.