How to regulate nanotechnology and the application of nanomaterials has been quite a controversial issue in recent years. While for instance non-governmental organizations (NGOs) like Greenpeace and Friends of the Earth consider the existing regulatory situation to be inadequate and are urging a strictly precautionary approach, industry representatives are instead seeking the development of specific guidance and standards to support implementation of existing regulations, which are generally seen as adequate. Researchers have used Multicriteria Mapping (MCM) to study why some regulatory options - bans, moratoriums, voluntary measures, etc. - are deemed to be acceptable/unacceptable by various stakeholders in the U.S. and the criteria they use to evaluate the different regulatory options. Not surprisingly, the largest difference in ranking of the policy options can be observed between environmental NGOs and the representatives from the industrial companies and the trade association.