California Code, Elections Code - ELEC § 8902

(a) Notwithstanding any other law, the name of a candidate for Governor shall not be printed on a direct primary election ballot, unless the candidate, at least 88 days before the direct primary election, files with the Secretary of State copies of every income tax return the candidate filed with the Internal Revenue Service in the five most recent taxable years, in accordance with the procedure set forth in Section 8903.

(b) If the candidate has not filed the candidate's income tax return with the Internal Revenue Service for the tax year immediately preceding the primary election, the candidate shall submit a copy of the income tax return to the Secretary of State within five days of filing the return with the Internal Revenue Service.

(c) The requirement in subdivision (a) does not apply to any year in which the candidate was not required to file the candidate's income tax return with the Internal Revenue Service.