The US Securities and Exchange Commission (SEC) has reopened its investigation into Neuralink, Elon Musk’s brain-implant company, alongside a probe into Musk’s acquisition of Twitter, now rebranded as X.

Maintaining its policy of secrecy about investigations, the SEC has not responded to the letter or confirmed the demands. According to Spiro's letter, federal law requires Musk to reveal his ownership in Twitter once it rises above 5%, but he did not do so. Musk apparently delayed openness for investors until his holding peaked at 9%, instead.

The U.S. Securities and Exchange Commission (SEC) this week has reopened an investigation into Elon Musk's brain-chip startup Neuralink, according to a letter shared by Musk on Thursday on social media platform X.

Elon Musk criticizes the SEC for its recent demands regarding his Twitter acquisition and the reopening of the Neuralink investigation.

Elon Musk renewed his longstanding feud with the Securities and Exchange Commission by posting a letter that said the agency is investigating his brain-computer interface company, Neuralink Corp.

Musk has long sparred with SEC and last year four lawmakers asked to investigate whether Musk committed securities fraud by allegedly misleading investors about brain implant developed by Neuralink.

The Dec. 12 letter from Musk's lawyer Alex Spiro and addressed to outgoing SEC Chair Gary Gensler also noted that the commission had issued a settlement demand and that Musk had been given 48 hours to accept a a monetary payment or face charges on multiple counts.

Elon Musk has reignited his feud with the Securities and Exchange Commission (SEC) in full view of the public as regulators take another look into his brain-chip venture Neuralink.

Tech mogul Elon Musk criticized the Securities and Exchange Commission (SEC) on Thursday over a settlement offer in the agency’s probe into his 2022 purchase of Twitter, now known as X. In a letter to SEC Chair Gary Gensler that Musk shared on X,