Tesla Inc. CEO Elon Musk believes he had a verbal agreement in place with Saudi Arabia’s sovereign-wealth fund to help finance a plan to take the auto maker private, according to a person familiar with the matter, a contention that could preview how he will fight regulators’ accusation that he misled shareholders.
Mr. Musk was sued Thursday by the Securities and Exchange Commission, which alleged that he misled investors when he tweeted last month that he had funding secured to lead a Tesla buyout. The agency, which is seeking...