One of the most common misconceptions when registering a trademark is believing that IMPI grants exclusivity over a word throughout Mexico. It does not. Exclusivity operates within the line of business the mark was registered in.
Internationally, goods and services are grouped into 45 categories under the Nice Classification. If one company sells clothing (Class 25) and another opens a restaurant (Class 43) under the same name, both marks can legally coexist: because they do not compete for the same consumer, no confusion arises.
The best-known example in Mexico is Corona. The beer is registered in Class 32. The laundry soap, in Class 3. The hardware tools, in Classes 6, 7 and 8. They are identical marks, with different owners and different industries, and all three are valid because they live in different classes.
The real risk is not that someone else uses your word. The real risk is choosing the wrong class. If you registered in a category that does not match what you actually sell, your flagship product may be unprotected against competitors — and you will find out when it is already too late.
That is why choosing your classes is not an administrative formality: it is a strategic decision that defines how far your protection reaches.
When coexistence is the right answer
Two businesses can hold the same word in different classes, and often the commercially sensible outcome is not a fight but a written coexistence agreement: who uses what, in which classes and territories, with what visual differences, and an undertaking not to oppose each other.
That is usually cheaper and faster than an opposition, which in any case has to be filed within one month of the application being published (article 221 of the Mexican Industrial Property Law).
Two cautions before relying on class separation. The grounds in article 173 cover goods or services that are similar, not only identical, so neighbouring classes are not automatically safe. And a mark the Institute considers or has declared notoriously known or famous is protected against any products or services (article 173, fractions XVI and XVII), which overrides the class logic entirely.