Prob. Code, § 16336

(a) A unitrust plan shall provide the method for determining the fair market value of an asset for the purpose of determining the unitrust amount, including both of the following:

(1) The frequency of valuing the asset, which need not require a valuation in every period.

(2) The date for valuing the asset in each period in which the asset is valued.

(b) Except as otherwise provided in paragraph (2) of subdivision (b) of Section 16338, a unitrust plan may provide methods for determining the amount of the net fair market value of the trust to take into account in determining the applicable value, including all of the following:

(1) Obtaining an appraisal of an asset for which fair market value is not readily ascertainable.

(2) Exclusion of specific assets or groups or types of assets.

(3) Exceptions or modifications of the treatment of specific assets or groups or types of assets.

(4) Identification and treatment of money or property held for distribution.

(5) Use of either of the following:

(A) An average of fair market values over a stated number of preceding periods.

(B) Another mathematical blend of fair market values over a stated number of preceding periods.

(6) A limit on how much the applicable value of all assets, groups of assets, or individual assets may increase over either of the following:

(A) The corresponding applicable value for the preceding period.

(B) A mathematical blend of applicable values over a stated number of preceding periods.

(7) A limit on how much the applicable value of all assets, groups of assets, or individual assets may decrease below:

(A) The corresponding applicable value for the preceding period.

(B) A mathematical blend of applicable values over a stated number of preceding periods.

(8) The treatment of accrued income and other features of an asset that affect value.

(9) Determining the liabilities of the trust, including treatment of liabilities to conform to the treatment of assets under paragraphs (1) to (8), inclusive.