California Code, Insurance Code - INS § 1996

In marine insurance, where an insured has a demand against others for contribution, he may claim the whole loss from the insurer, subrogating the insurer to the insured's right to contribution.  But no such claim can be made upon the insurer after the separation of the interests liable to contribution, nor after the insured, having the right and opportunity to enforce contribution from others, neglects or waives the exercise of that right.