Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
Subsidiary is regular. It follows the -ies Conversion rule.
Use plural verbs: "The subsidiaries are ready" (not "is ready").
Yes. The plural subsidiaries is standard across all English variants.
The word subsidiary follows the standard English pluralization rule. When forming the plural, subsidiary becomes subsidiaries. This follows the -ies Conversion pattern, which is one of the most common plural rules in English.
Understanding why subsidiary becomes subsidiaries helps with spelling and pronunciation. Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
When using subsidiaries in writing, remember that it functions as a plural noun in sentences. It pairs with plural verbs and pronouns. For example: "The subsidiaries are ready" (not "is ready"). This subject-verb agreement is essential for grammatical correctness.