Texas Estates Code - EST § 1161.002. Standard for Management and Investment of Estate

(a) In acquiring, investing, reinvesting, exchanging, retaining, selling, supervising, and managing a ward's estate, a guardian of the estate shall exercise the judgment and care under the circumstances then prevailing that a person of ordinary prudence, discretion, and intelligence exercises in the management of the person's own affairs, considering the probable income from, probable increase in value of, and safety of the person's capital. The guardian shall also consider all other relevant factors, including:

(b) In determining whether a guardian of the estate has exercised the standard of investment required by this section with respect to an investment decision, the court shall, absent fraud or gross negligence, consider the investment of all the estate assets over which the guardian has management or control, rather than considering the prudence of only a single investment made by the guardian.