CA Gov't Code Section 84503

(a)

Any advertisement for or against any ballot measure shall include a disclosure statement identifying any person whose cumulative contributions are fifty thousand dollars ($50,000) or more.

(b)

If there are more than two donors of fifty thousand dollars ($50,000) or more, the committee is only required to disclose the highest and second highest in that order. In the event that more than two donors meet this disclosure threshold at identical contribution levels, the highest and second highest shall be selected according to chronological sequence.