Elon Muskwill testify in court again as part of the Securities and Exchange Commission's investigation into his $44-billion takeover ofTwitter.

Laurel Beeler, federal judge in San Francisco, told lawyers representing theTeslaCEO that Musk will have to endure another day in court. Musk's legal team argued the SEC does not have the authority to issue subpoenas, a claim that was quickly rejected by Beeler.

Lawyers for the regulator argued the SEC has new documents relating to the takeover and that Musk must answer further questions.

Beeler said that the SEC has "broad investigative powers" and...