The Coca-Cola Company has been trying to register the trademark ZERO for its low calorie, zero sugar version of Coca-Cola, but is facing opposition from Dr Pepper Snapple Group (known for SCHWEPPES), although a decision from the United States Patent and Trademark Office (USPTO) is expected during this year.
If Coca-Cola manages to win the case and register the trademark, they will be able to prevent other competitors from using the word ZERO or other confusingly similar signs to identify related good. On the other hand, if Coca-Cola loses the case, competitors will be free to use the word ZERO to identify their own goods.
One of the main claims is that ZERO is merely describing that the drink contains zero sugar and is thus not distinctive, although Coca-Cola might try to argue that ZERO is a suggestive mark and does not necessarily describe low calorie products.
All things considered, even if there is a low probability of having ZERO registered as a trademark, the increasing market for low calorie drinks makes it worth the risk.