Engineer accused of insider trading tied to Microsoft's reboot of Three Mile Island nuclear plant
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Engineer accused of insider trading tied to Microsoft's reboot of Three Mile Island nuclear plant
SEC claims former Constellation employee made $1.4M trading options before the restart deal was announced
Lindsay Clark
Lindsay<br>Clark
Published<br>fri 26 Jun 2026 // 11:44 UTC
A former Constellation Energy engineer has been accused of making $1.4 million from insider trading ahead of the company's announcement that it would restart a reactor at Three Mile Island to supply power to Microsoft.<br>The Securities and Exchange Commission (SEC) and federal prosecutors allege in their lawsuits that Casey Muggleston purchased share options based on knowledge officially deemed material non-public information (MNPI).<br>In September 2024, Microsoft and Constellation Energy – which owns the Three Mile Island facility – signed a 20-year power purchase agreement to bring TMI Unit 1 back online after it was retired in 2019. Earlier this month, the Nuclear Regulatory Commssion made a preliminary finding [PDF] that the proposed restart would not significantly affect the environment. The assessment remains subject to public comment and a final determination.
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According to a filing in the US District Court for the District of Delaware, Muggleston knew he was barred from trading on MNPI or buying options in Constellation stock.<br>The criminal indictment claims that in May 2024, he became aware of the plan for the company to restart the Three Mile Island reactor through his work as a nuclear engineer at Constellation.<br>He "exploited that MNPI in violation of the duties of trust and confidence owed to the energy company and its shareholders," the filing alleges, through a series "call options" on company shares between June and September for a total of around $66,595.
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In July 2024, directors authorized the $1.5 billion restart project. On September 20, the company issued a public statement about its plans to reopen the facility, along with Microsoft's involvement. The company's shares started the day trading at $181.80 and ended the day at $254.98.<br>"After the announcement, Muggleston sold all his Constellation call options. In so doing, he made approximately $1.4 million," the SEC filing said.<br>The SEC also said that the engineer "continued to express an interest in trading on material nonpublic information in violation of his duty to Constellation."<br>Representatives of the parties are not responding to requests for comment.<br>In the federal case, taking place in Wilmington, Delaware, Muggleston is set to make an appearance on July 2 before Judge Sherry R Fallon. ®
microsoft<br>nuclear power<br>systems
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