California Code, Business and Professions Code - BPC § 17075

In any action where it is alleged and shown that the person complained against is selling below his cost of doing business, and such person is including labor at less than the prevailing wage scale in the trade in which such person is engaged for the locality or vicinity in which he is doing business, evidence of such prevailing wage scale shall be admissible to prove the intent or purpose of such person to violate this chapter.