Enterprise Resource Planning (ERP) represents a general business application software solution which is applicable in different business operations. Therefore, it covers areas which are common to a certain group of business operations (e.g. manufacturing, services, financial services, public services, etc.). However, business operations, no matter if they belong to the same or different group, have specific areas which are not supported in general ERP solutions. This paper attempts to reveal which business operations are supported by specialized ERP solutions, how to measure the size of specialized ERP producers, how many business operations are supported by ERP producers on average, and whether there are any classifications of ERP producers based on the number of supported business operations.