So the company is owned by 3 companies, which in my understanding should be a joint venture. Shall we use proportionate instead of consolidation method?
no, in a joint venture you have JOINT CONTROL
consolidation = acquisition method.
since Cupercino has CONTROL, not JOINT CONTROL , you use Ac. Method.
the other are equity since they do not have joint control or control. anyway since it’s a US GAAP probleme even if they had JOINT control they would have been consolidated with Equity method
Joint control is usually a 50%/50% split between 2 companies. However, this control could be shared equally 1/3 between 3 investors, 1/4 between 4 investors etc