Civ. Code, § 731.08

Where any part of the principal consists of bonds or other obligations for the payment of money, they shall be deemed principal at their inventory value as fixed by the appraiser or appraisers regularly appointed by the court, or, in default thereof, at their market value at the time the principal was established, or at their cost where purchased later, regardless of their par or maturity value; and upon their respective maturities or upon their sale or other disposition any loss or gain realized thereon shall fall upon or inure to the principal, except in the case of property referred to and defined by Section 731.14, in which case the provisions of Section 731.14 shall govern. Where any part of the principal consists of a bond or other obligation for the payment of money, bearing no stated interest but redeemable at maturity or a future time at an amount in excess of the amount in consideration of which it was issued, such accretion, as when realized, shall inure to income.