This report describes the laws of eight European countries—Belgium, Ireland, Italy, Liechtenstein, Luxembourg, the Netherlands, Spain, and Switzerland—that prohibit investment in certain controversial weapons.Controversial weapons are those that are either prohibited under international conventions or are deemed particularly controversial because of their humanitarian impact. They include weapons of mass destruction such as nuclear, chemical and biological weapons, and weapons that fail to discriminate between civilians or combatants or cause disproportionate harm, such as cluster munitions or anti-personnel mines. International conventions that regulate or prohibit controversial weapons include those covering nuclear weapons, chemical weapons, biological weapons, cluster munitions, anti-personnel mines, and inhumane conventional weapons. One of these conventions, the Convention on Cluster Munitions, has language that has been widely interpreted as requiring States Parties to prohibit investment in producing such weapons.