Regulatory knowledge, as the ensemble of experiences, information, data or simulations that constitute regulatory objects, or qualify medicines for regulatory intervention, come from a potentially diverse set of fields - from the pharmaceutical industry itself to the product testing industry, through academic or regulatory science centers and to a lesser extent health professionals and patients. The talk will outline a framework to analyze the relative weight of the actors pertaining to these fields in the selection of regulatory knowledge, and the dependence of public experts on privately produced regulatory knowledge.