Cal. Civ. Code § 1916.6
A security document, or evidence of debt issued in connection therewith, executed pursuant to Section 1916.5 may provide that the rate of interest shall not change until five years after execution of such document or documents, and not more frequently than every five years thereafter. In every security document, or evidence of debt issued in connection therewith, executed pursuant to this section all the provisions of Section 1916.5 shall be applicable, except those provisions specifying the frequency of interest rate changes and limiting rate changes to one-fourth of 1 percent in any semiannual period. For the purposes of this section "five years" means each of the successive periods of five years commencing with the first day of the calendar month in which the instrument creating the obligation is dated.
Ca. Civ. Code § 1916.6