reserve bank vs banking company

reserve bank and banking company both are nouns.

Word	Noun	Adjective	Verb	Adverb
reserve bank	Yes	No	No	No
banking company	Yes	No	No	No

As nouns, banking company is a hypernym of reserve bank; that is, banking company is a word with a broader meaning than reserve bank:

reserve bank: one of 12 regional banks that monitor and act as depositories for banks in their region
banking company: a financial institution that accepts deposits and channels the money into lending activities

Other hypernyms of reserve bank include bank, banking concern, depository financial institution.

reserve bank (noun)	banking company (noun)
one of 12 regional banks that monitor and act as depositories for banks in their region	a financial institution that accepts deposits and channels the money into lending activities