You keep seeing the TM or R-in-a-circle in superscript beside a trademark, but what does it really mean?
When a trademark is in the application stage, or is in use in an unregistered trademark sense, then the TM (™) works well to provide notice that the name is being used as a trademark. Unregistered marks are useful for subset brands, or when the marks are too descriptive to be entered into the Principal Register.
When the trademarks are registered in the US Federal Register, they may be used with the R-in-a-circle ®. This is the only registration that allows the use of that symbol, not state trademark registrations nor foreign registered trademarks. If you see misuse of the R-in-a-circle, it can be reported to the Federal Trade Commission and, in some cases, is a federal offence.