GM crops are concentrated within a few seed companies, allowing them to control the worldwide food supply. Other reasons are based on ethics or religion (Finucane and Holup, 2005). Labeling of GM Food Products So far, none of the GMOs that farmers commercially cultivate has been demonstrated to be more unsafe for human consumption or the environment than their non-GM counterparts (National Academies of Sciences and Medicine, 2016). Nevertheless, many consumers are concerned for various reasons. As with most safety and process attributes, consumers cannot distinguish GM from non-GM products before or after consumption, which makes the GMO attribute a credence attribute (Caswell, 1998; Darby and Karni, 1973). For example, consumers cannot reliably judge whether the maize chips they are buying were produced from GM or non-GM maize, or whether the sugar in their soda comes from GM or non-GM sugar beet. Inspection tests can identify the GMO attribute in the first example if the chips were produced from GM maize, but these tests cannot identify the GM attribute in sugar because sugar from GM sugar beet does not contain (or contains very small amounts of) DNA. First-generation GM and non-GM products are often considered to be vertically differentiated, as consumers are either indifferent or prefer the non-GM product if offered at the same price as the GM product (e.g., Fulton and Giannakas, 2004; Lapan and Moschini, 2007). Independent of whether the product contains the GMO or not, the EU GMO regulation requires that manufacturers label all products from GM crops (European Commission, 2003a, ,b). The EU GMO regulation on positive mandatory labeling has been in place since the early 2000s. Shortly after the import of the first GMOs into the European Union, some retailers began to exclude GM store brands from their shelves (Kalaitzandonakes and Bijman, 2003). Already in the early 2000s, most EU retailers and manufacturers excluded most GM products to avoid protests by anti-GMO activist groups and the risk of boycotts (Gruère, 2006). The United Kingdom is one of the EU Member States with a few GM-labeled products (GM Freeze Online, 2017). Labeling of Non-GMO Food Products Even though retailers hardly offer any GM-labeled products in Europe, GM crops are widely used in food production. These GM crops are mostly used for feeding animals. Feeding GM crops to animals does not require labeling of the final livestock product because the GMO regulation exempts products that are derived with (the help of) GMOs (i.e., products in which manufacturers use GMOs in the production process only) from positive mandatory labeling 6 (European Commission, 2003b). For example, fresh milk derived from cows that consumed GM soybean meal is not required to be labeled as a GM product. The exemption also concerns the use of GM enzymes or other GM additives. However, some EU Member States have developed voluntary non-GMO certification standards to label products that limit the use of GMOs in the production process. In the European Union, the curren...