stockholdings vs stockholding

stockholdings and stockholding both are nouns.

Word	Noun	Adjective	Verb	Adverb
stockholdings	Yes	No	No	No
stockholding	Yes	No	No	No

As nouns, stockholdings and stockholding are synonyms defined as:

stockholdings and stockholding: a specific number of stocks or shares owned

stockholdings (noun)	stockholding (noun)
a specific number of stocks or shares owned	ownership of stocks; the state or fact of holding stock
	a specific number of stocks or shares owned