In addition to such other investments that are authorized by this article, the retirement board may, in its discretion, invest the assets of the retirement fund in deeds of trust and mortgages. Investments made under this section shall not exceed, in the aggregate, an amount equal to 25 percent of the assets of the system.
Source:
Section 12365.6, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=PUC§ionNum=12365.6..