Trademarks, specifically word marks, are generally not case-sensitive. The protection of a word mark extends to the specific wording and combination of letters, regardless of the case used.
When you register a word mark, the focus is on protecting the distinctive textual content of the mark itself, rather than the case sensitivity. This means that trademarks are typically considered to cover all variations of capitalization, including all uppercase, all lowercase, or a mix of both.
For example, if you register a word mark in all uppercase letters, you would still have protection for that mark if someone else attempted to use it in all lowercase or a combination of uppercase and lowercase letters.
However, it's important to note that this general rule applies to the textual content of the mark. If your mark includes design elements or stylization that are case-specific and contribute to its distinctiveness, those elements may be protected as part of the overall mark.