Private professional fiduciaries are typically individuals who hold themselves out as experts in serving as Trustees of trusts. These individuals may come from a variety of backgrounds, including accounting and law. To be a private professional fiduciary in California, the individual must adhere to the requirement of the Professional Fiduciaries Act as provided in California Business and Professions Code Sections 6500 to 6592. (See also California Probate Code Section 2340). 

Despite licensing requirements, private professional fiduciaries may have different levels of competence and capability, so interviewing and determining a candidate's qualifications is important. 

It's important to also note that private professional fiduciaries may not be expected to provide the full range of services that a corporate trustee would, such as investment advisory. As a result, utilizing a private professional fiduciary may require additional fees for ancillary services. That being said, a private professional fiduciary may be more flexible in terms of dealing with sensitive family dynamics involving beneficiaries as they are typically individuals who are directly dealing with the relevant parties.

You can find a list of licensed private professional fiduciaries on the website of the Professional Fiduciary Association of California (www.pfac-pro.org).