If the brand name has the TM symbol as a suffix, this means that the trademark is not registered. You can use only the TM symbol, even if you have started the process of registering your trademark, not the ® sign. The trademark symbol sends a signal to potential infringers that you are claiming the right to a trademark. If someone infringes a trademark, the remedy is not a legal remedy prescribed by law, this is a common law remedy.
The symbol ® means that the trademark is registered (the registration process is completed). Once your trademark registration has been approved by the appropriate authority and published in the Trademark Registry, you can use the ® symbol. This means that any violation will mean that the injured party can resort to legal remedies prescribed by law and demand compensation from the violator.
It is important to remember that you cannot use the ® symbol for an unregistered trademark. In particular, you cannot use the ® symbol in your trademark until it is registered. You can use only the TM symbol for an unregistered trademark.
It is regulated by common practice worldwide. Despite on it is not regulated by law in Ukraine. It's the right of the trademark owner but not the obligation.