From the SEC website: Who is an insider? An “insider” is an officer, director, 10% stockholder and anyone who possesses inside information because of his or her

From the SEC website: Who is an insider? An “insider” is an officer, director, 10% stockholder and anyone who possesses inside information because of his or her relationship with the Company or with an officer, director or principal stockholder of the Company. A principal shareholder is a person that directly or indirectly owns or controls more than 10% of any class of voting shares or securities of a company. The principal shareholder has the authority to vote using those voting shares. Elon has less than 10% share (9.2%), so he's not an insider. Probably he stayed under 10% because of this law.