Tesla has received a second subpoena from the US Securities and Exchange Commission over its Chief Executive Elon Musk's tweets in 2018 about taking the company private, the electric automaker disclosed in a regulatory filing.

The company said it received the subpoena on June 13 and will cooperate with the government authorities.

The regulator did not immediately respond to a Reuters request for comment.

In November last year, the regulator had subpoenaed Tesla related to a settlement that required Musk's tweets on material information to be vetted.

Musk had in 2018 settled a lawsuit by the regulator over his go-private tweets by agreeing to let the company's lawyers pre-approve tweets with material information about the company.

In June, Musk appealed a judge's refusal to end this 2018 agreement with the SEC.

Separately, Tesla said it has converted about 75% of its bitcoin holdings into fiat currency and has recorded an impairment charge of $170 million related to the asset.

As of June 30, the fair market value of its digital assets was worth $222 million, it said in the filing