Here's why:
* Punctuation marks the end of a phrase or sentence.
* The trademark symbol is a modifier, indicating a brand name.
Think of it like this:
* You wouldn't put a comma or period *inside* a word.
* Similarly, you wouldn't put punctuation inside the trademark symbol's "modifier" role.
Examples:
* Correct: "This is a product of Brand Name™."
* Incorrect: "This is a product of Brand Name™,."
* Correct: "Did you see the new Brand Name® product?"
* Incorrect: "Did you see the new Brand Name®? product?"
Exceptions:
* If the trademark symbol is part of a larger phrase, like a tagline, the punctuation may go before or after it, depending on the specific phrase structure. For example, "Just do it.™"
* In some cases, specific style guides or company policies may dictate different placement.