If a consolidated return is made subject to the provisions of this article, the tax imposed under this chapter shall be computed as a unit upon the consolidated net income of the group except as hereinafter provided. The parent corporation and each subsidiary, a member of the group during any part of a consolidated period, shall be severally liable for the tax, including any deficiency in respect thereof, computed upon the consolidated net income of the group. If a subsidiary by reason of a bona fide sale of stock for fair value has ceased to be a member of the affiliated group, its liability shall remain unchanged, except that if such cessation occurred prior to the date
upon which any such deficiency is assessed, such deficiency, in the case of such former subsidiary, shall be reduced to an amount equal to such part as may be allocable to it upon the basis of the consolidated net income properly assignable to it. In no case, however, shall any demand for the payment of any deficiency be made, or any proceeding in court for the collection thereof be begun against such former subsidiary prior to the determination by the Franchise Tax Board that the amount of the deficiency cannot be collected from the parent corporation and the corporations, if any, remaining members of the affiliated group.