Tesla boss Elon Musk is seeking to overrule a 2018 court ruling that partially took away control of his Twitter account.
The multi-billionaire was subpoenaed by the US Securities and Exchange Commission five years ago after tweeting false information about Tesla.
He wrote that funding had been secured to potentially take the EV firm private at $420 a share. However, no such buyout was close.
The post, which drove up Tesla’s share price, ended up costing Tesla and Musk $20m each in civil fines with restrictions placed on what he could write on the social media platform.
The agreement also forced Musk to resign as chairman of the board.
As per the court ruling, lawyers have since been allowed to vet some of Musk’s communications in advance.
The veto includes Twitter posts that could affect Tesla’s stock price but the boss has now moved to have the restrictions removed.
In a motion filed on Tuesday in US District Court in Manhattan, Musk’s lawyer Alex Spiro contends that the subpoena from the SEC has no basis in law.
He also says the regulator cannot take action about Mr Musk’s tweets without court authorisation.
Spiro says the SEC has used the court agreement ‘to trample on Mr Musk’s First Amendment rights and to impose prior restraints on his speech’.
The SEC has in the past denied issuing subpoenas in the Musk Twitter case.
Spiro’s motion asks Judge Nathan to scrap the agreement, alleging the SEC is using it and ‘near limitless resources’ to chill Musk’s speech.
It says Musk signed the agreement when Tesla was a less mature company and SEC action jeopardised the company’s financing.
It also claims the SEC subpoenaed Tesla in November after Musk tweeted about a plan to sell 10 per cent of his Tesla stock to pay taxes.
The subpoena sought information about whether he received approval from Tesla before his tweets, and how the firm complied with the court agreement.
Mr Spiro contends the subpoena is one in a ‘winding parade’ of investigations into Mr Musk and his companies that are being done without factual basis.