Two symbols, two different meanings
™ (Trademark)
Use this symbol on a mark that has not been registered. It signals that you are claiming the mark as yours.
® (Registered Trademark)
This symbol is reserved for marks that have been officially registered with the USPTO or CIPO. Do not use it before registration is complete.
In short: ™ is for marks you are claiming, while ® is only for marks that are registered.