Are you sure that none of your employees have a criminal background? Honest and sincere employees are very crucial to your business because they work like a team in order to improve your overall business. Hence, you have to be very sure that your team does not have any one with criminal background. Though, a lot of people claim that interviews are the best way to judge the character of a person, it is certainly not enough to find out if the employee is telling the truth or everything they say is fabricated with false documents and fake certificates.
Giant corporations and multinationals who are more worried about their business are more worried about hiring better employees because they have a large scale business to handle and therefore they have thousands of workers and employees who are working for them, but that is exactly where the chances of making mistakes are more likely to happen. People with criminal backgrounds prefer such large scale organizations because they are easy to penetrate. These companies often do not hire their employees directly but they hire a third party recruiter who does the hiring part and than selects the employees. Hence, there are less background checks and investigations in this scenario.
On the other hand, smaller businesses prefer to keep away from background checks because they feel that they are too small for that. Employers who have just started their business would not go for criminal background investigation because they feel that their organization is too young for all that processes. Many people who are expert in social engineering prefer to stick to smaller companies because they have more chances of going up the corporate ladder quickly and since they are working for a company from very initial stages they have access to almost all the information and trade secrets.