Tesla said in a filing that it received the subpoena on June 13. The regulator had initially subpoenaed the company in November related to a settlement that required Musk's tweets on material information to be vetted.
The company said on Monday it will cooperate with the government authorities. The SEC declined to comment.
The November subpoena came days after Musk asked his Twitter followers whether he should sell 10% of his Tesla stake to cover tax bills on stock options.
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.
The world's richest person, who calls himself a "free speech absolutist", has said his "funding secured" tweet was truthful, likening himself to rapper Eminem in seeking to throw out his 2018 agreement with the SEC. read more
Musk is also facing a lawsuit from Twitter for dropping his $44-billion offer to buy the social media company and is now preparing for a legal showdown in a trial set to begin in October.