Cal. Probate Code § 2401

(a) The guardian or conservator, or limited conservator to the extent specifically and expressly provided in the appointing court’s order, has the management and control of the estate and, in managing and controlling the estate, shall use ordinary care and diligence. What constitutes use of ordinary care and diligence is determined by all the circumstances of the particular estate. (b) The guardian or conservator: (1) Shall exercise a power to the extent that ordinary care and diligence requires that the power be exercised. (2) Shall not exercise a power to the extent that ordinary care and diligence requires that the power not be exercised. (c) Notwithstanding any other law, a guardian or conservator who is not a trust company, or an employee of that guardian or conservator, in exercising their powers, may not hire or refer any business to an entity in which the guardian or conservator or an employee has a financial interest. For the purposes of this subdivision, “financial interest” shall mean (1) an ownership interest in a sole proprietorship, a partnership, or a closely held corporation, or (2) an ownership interest of greater than 1 percent of the outstanding shares in a publicly held corporation, or (3) being an officer or a director of a corporation. (d) Subdivision (c) does not prohibit a professional fiduciary appointed as a guardian or conservator from hiring and compensating individuals as employees, with court approval. (e) (1) Notwithstanding any other law, a guardian or conservator who is a trust company, in exercising its powers may not, except upon authorization of the court, invest in securities of the trust company or an affiliate or subsidiary, or other securities from which the trust company or affiliate or subsidiary receives a financial benefit or in a mutual fund, other than a mutual fund authorized in paragraph (5) of subdivision (a) of Section 2574, registered under the Investment Company Act of 1940 (Subchapter 1 (commencing with Sec. 80a-1) of Chapter 2D of Title 15 of the United States Code), to which the trust company or its affiliate provides services, including, but not limited to, services as an investment adviser, sponsor, distributor, custodian, agent, registrar, administrator, servicer, or manager, and for which the trust company or its affiliate receives compensation. (2) Before authorization from the court, the guardian or conservator shall disclose to the court in writing the trust company’s financial interest.