California Code, Financial Code - FIN § 14766

(a) An officer, as described in Section 14500, a director, or an employee of a credit union shall not purchase, directly or indirectly, or be interested in the purchase of, any of the credit union's obligations for an amount less than the book value thereof, unless all the directors of the credit union previously approve the purchase by resolution and a copy of the resolution is delivered to the commissioner immediately after adoption. Every person who violates this section shall be liable to the people of this state for each offense in an amount of up to twice the book value of the obligations purchased.

(b) The method used for determining book value shall be set forth in a written policy governing the sale of credit union obligations established and approved by the board of directors. The method used shall be consistent with generally accepted accounting principles.