Registered trademark symbol

The registered trademark symbol, , is a typographic symbol that provides notice that the preceding word or symbol is a trademark or service mark that has been registered with a national trademark office. A trademark is a symbol, word, or words legally registered or established by use as representing a company or product. In some countries it is against the law to use the registered trademark symbol for a mark that is not officially registered in any country.
Unregistered trademarks can instead be marked with the trademark symbol, , while unregistered service marks are marked with the service mark symbol, . The proper manner to display these symbols is immediately following the mark; the symbol is commonly in superscript style, but that is not legally required. In many jurisdictions, only registered trademarks confer easily-defended legal rights.
In the US, the registered trademark symbol was originally introduced in the Trademark Act of 1946.
Because the symbol is not commonly available on typewriters (or ASCII), it was common to approximate it with the characters ' (or '). Example of legal equivalents are the phrase "Registered, U.S. Patent and Trademark Office", which may be abbreviated to "Reg U.S. Pat & TM Off." in the US.
Computer usage.
The registered trademark character was added to several extended ASCII character sets, including ISO-8859-1 from which it was inherited by Unicode as . This is a different character from as many fonts draw the registered trademark symbol smaller and possibly superscripted.