Gov. Code, § 84305

(a) (1) Except as provided in subdivision (b), a candidate, candidate controlled committee established for an elective office for the controlling candidate, or political party committee shall not send a mass mailing unless the name, street address, and city of the candidate or committee are shown on the outside of each piece of mail in the mass mailing and on at least one of the inserts included within each piece of mail of the mailing in no less than 6-point type that is in a color or print that contrasts with the background so as to be easily legible. A post office box may be stated in lieu of a street address if the candidate’s, candidate controlled committee established for an elective office for the controlling candidate’s, or political party committee’s address is a matter of public record with the Secretary of State.

(2) Except as provided in subdivision (b), a committee, other than a candidate controlled committee established for an elective office for the controlling candidate or a political party committee, shall not send a mass mailing that is not required to include a disclosure pursuant to Section 84504.2 unless the name, street address, and city of the committee is shown on the outside of each piece of mail in the mass mailing and on at least one of the inserts included within each piece of mail of the mailing in no less than 6-point type that is in a color or print that contrasts with the background so as to be easily legible. A post office box may be stated in lieu of a street address if the committee’s address is a matter of public record with the Secretary of State.

(b) If the sender of the mass mailing is a single candidate or committee, the name, street address, and city of the candidate or committee need only be shown on the outside of each piece of mail.

(c) (1) A candidate, candidate controlled committee established for an elective office for the controlling candidate, or political party committee shall not send a mass electronic mailing unless the name of the candidate or committee is shown in the electronic mailing preceded by the words “Paid for by” in at least the same size font as a majority of the text in the electronic mailing.

(2) A committee, other than a candidate controlled committee established for an elective office for the controlling candidate or a political party committee, shall not send a mass electronic mailing that is not required to include a disclosure pursuant to Section 84502 or 84504.3 unless the name of the committee is shown in the electronic mailing preceded by the words “Paid for by” in at least the same size font as a majority of the text in the electronic mailing.

(d) If the sender of a mass mailing is a controlled committee, the name of the person controlling the committee shall be included in addition to the information required by subdivision (a) or (c).

(e) For purposes of this section, the following terms have the following meanings:

(1) “Mass electronic mailing” means sending more than 200 substantially similar pieces of electronic mail within a calendar month. “Mass electronic mailing” does not include a communication that was solicited by the recipient, including, but not limited to, acknowledgments for contributions or information that the recipient communicated to the organization.

(2) “Sender” means the candidate, candidate controlled committee established for an elective office for the controlling candidate, or political party committee who pays for the largest portion of expenditures attributable to the designing, printing, and posting of the mailing which are reportable pursuant to Sections 84200 to 84216.5, inclusive.

(3) To “pay for” a share of the cost of a mass mailing means to make, to promise to make, or to incur an obligation to make, any payment: (A) to any person for the design, printing, postage, materials, or other costs of the mailing, including salaries, fees, or commissions, or (B) as a fee or other consideration for an endorsement or, in the case of a ballot measure, support or opposition, in the mailing.

(f) This section does not apply to a mass mailing or mass electronic mailing that is paid for by an independent expenditure.