The Securities and Exchange Commission inquired about the delay in revealing Musk's purchase of a stake in Twitter.

In a letter dated April 4 but only published by the SEC on Friday, Musk is asked a series of questions about his stake in the social media platform that he has offered to buy for $44 billion.

On April 4, Musk revealed a 9.2% stake in the company, the same day that the SEC sent a letter to the company.

He joined the board a day later, but reversed his decision before his $54.20 a share bid was accepted by the board.

Musk stated in his initial filing that he had purchased more than 73 million shares on March 14. He had to reveal his filing 10 days after the purchase.

Please advise us why the Schedule 13G does not appear to have been made within the required 10 days from the date of acquisition as required by Rule 13d-1(c), the rule upon which you relied to make the submission, according to the letter.

A 13G filing needs to be made when a shareholder has more than 5%. Musk did not state in his original filing that a 5% holding had been exceeded.

Musk made a number of comments in the aftermath of his purchase but before it was publicly disclosed, including running a poll asking users about their perception of free speech on March 25, which the SEC highlighted.

Your response should address, among other things, your recent public statements on the Twitter platform regarding the issuer, including statements questioning whether the issuer complies with free speech principles.

One shareholder has sued Musk for market manipulation after weeks of public criticism of the company and put the deal on hold pending confirmation of the number of fake accounts on the platform.

Insider was told that Musk may be trying to lower the price to as little as $23 billion.

A request for comment from the SEC was not immediately responded to.