There is a 'coincidence of' interests between the companies. [=the companies share the same interests]
It was mere/pure/sheer 'coincidence' that brought them together so far from Chicago.
It was no 'coincidence' that he quit his job at the bank a day after the robbery.
(..) I thought of something. Hmm, for instance? Well, uh, for instance, supposing I told you that your fly was undone? By remarkable coincidence, so is yours. Oh, no, not again. Ah, I see you are familiar with the "open fly" ploy. Well, so am I. (..)1975 The Return of the Pink Panther