Dunnington v. State Fund [11/5/98] 1998 MTWCC 80 Claimant was injured while working for company with close ties to second company for which claimant had previously worked. Claimant argued the insurer should aggregate his earnings from both companies when calculating wage rate for purposes of permanent partial disability benefits. The Court refused. Under section 39-71-123(3), MCA (1995), the insurer is required to use the average actual earnings for the four pay periods immediately preceding injury unless the use of the last four pay periods does not accurately reflect the claimant's employment history with the employer and good cause requires use of additional weeks up to one year. Contrary to claimant's argument, the two companies were not the same employer where they were separate corporations and separate legal entities, kept separate accounts, paid their employees out of separate accounts, had their own employees – most of whom were not shared – and provided different services. The fact of common ownership is not sufficient to disregard the corporate veil where there was no evidence that one company was the alter ego, instrumentality or agent of the other or that one corporate entity was a subterfuge. The fact that, after injury, claimant was employed by one entity in a job created to accommodate him, and infrequently did work for the other entity, does not prove commingling where pre-injury he had been laid off by one company prior to beginning exclusive work for the other company.