capital gain vs financial gain

capital gain and financial gain both are nouns.

Word	Noun	Adjective	Verb	Adverb
capital gain	Yes	No	No	No
financial gain	Yes	No	No	No

As nouns, financial gain is a hypernym of capital gain; that is, financial gain is a word with a broader meaning than capital gain:

capital gain: the amount by which the selling price of an asset exceeds the purchase price; the gain is realized when the asset is sold
financial gain: the amount of monetary gain

capital gain (noun)	financial gain (noun)
the amount by which the selling price of an asset exceeds the purchase price; the gain is realized when the asset is sold	the amount of monetary gain