Is the use of the ® symbol obligatory if the trademark is registered?
In the vast majority of countries, use of the ® symbol in conjunction with a registered trademark or service mark is not obligatory; this applies in particular to Switzerland and all surrounding countries. In a few countries of Latin America (e.g. Mexico), of Africa, of the Middle and Far East, use appears to be obligatory or a condition for demanding extensive compensation for damages. In Portugal, use of the ® symbol is apparently obligatory for certain categories of products (pharmaceuticals, watches, certain luxury foodstuffs).