Few cases in the antitrust canon have been invoked more frequently, for the wrong reasons, than the Third Circuit’s 1977 decision in Bogosian v. Gulf Oil. For four decades now – culminating in the recent release of a decision certifying class in the long-running Mushrooms case – litigants and courts have cited a “presumption” or “short-cut” embedded in Bogosian and argued about whether it suffices to warrant class certification in a given case. This short-cut, however, is more fantasy than reality.