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