mercantile agency vs commercial agency

mercantile agency and commercial agency both are nouns.

Word	Noun	Adjective	Verb	Adverb
mercantile agency	Yes	No	No	No
commercial agency	Yes	No	No	No

As nouns, mercantile agency and commercial agency are synonyms defined as:

mercantile agency and commercial agency: an organization that provides businesses with credit ratings of other firms

mercantile agency (noun)	commercial agency (noun)
an organization that provides businesses with credit ratings of other firms	an organization that provides businesses with credit ratings of other firms