Musk’s X Sues Former Engineer Alleging Trade Secret Theft

Elon Musk’s X Corp. sued a former lead engineer, alleging she used the company’s trade secrets to build her own company after she made social media posts critical of Musk and was fired.

Former head of Infrastructure Optimization and Performance Yao Yue is accused of downloading to USB drives 6 million lines of the social media company’s proprietary source code to build her own company.

The code includes tools to run the X platform with “maximum efficiency and minimal resource expenditure—the very reason for X Corp.'s value and competitive success,” according to the complaint filed Thursday in the US District Court for the Northern District of California.

“Yue then launched IOP systems just days after her willful and malicious exfiltration occurred, offering customers services using those same specialized tools,” the complaint said.

Yue was fired in 2022 shortly after a post about Musk on social media that said, “Don’t resign, let him fire you.” A National Labor Relations Board judge in 2024 tossed her claims that X illegally fired her, saying she was a supervisor unprotected by federal law.

X said Yue took advantage of changes during Musk’s acquisition of the company to take the code undetected. She “bragged” to her former supervisor about taking the code, and tried to get employees to open source parts of the code after her firing, the complaint said.

Yue didn’t immediately respond to a request for comment.

The case is X Corp. v. Yue, N.D. Cal., No. 3:25-cv-10423, 12/4/25.