Spanish to English Bus/Financial Law: Taxation & Customs Certificate of Inscription

This term appear on a certificate of inscription that details the tax information of a business in Peru. The full phrase reads "GRAN ACTIVIDAD: SERVICIOS". I understand that this indicates that the business is primarily in the service industry, but I can't quite come up with the appropriate English translation. "ACTIVIDAD PRINCIPAL" is listed separately, which leads me to believe "Primary activity" would not be the best translation of "gran actividad".

Thanks for input on this.