Roughly one quarter of the billions in revenue lost by American businesses each year is stolen by employees. This is especially true for small-to-medium sized businesses, which sometimes lack the necessary security measures and infrastructure needed to convince employees that the risks of being caught outweigh the benefits of a little extra money.

A few things you can do to halt employee theft in its tracks:

1. Do your homework, before you hire. Check references, ask questions and get feedback on each person you bring onto your team. This is the best way to head off potential thieves.

2. Once you’ve made the hire, use the buddy system to keep employees accountable. If possible, there should never be a situation in which an employee closes alone. Closing time is the best time for theft to occur.

3. Know your employees as well as you can. If your company is too large for this, then make sure your managers and supervisors know what warning signs to watch: chronic lying, tendency to disregard corporate policy, substance abuse, overspending, and resentment or a feeling that they have been deprived of something.

4. If you are in retail, set up strict limits for when and how one employee can ring up another employee, and do not let employees ring up friends or relatives. All the most significant cash transactions and deposits should be made by you, or a trustworthy manager. If employees tend to consume some of your products, such as food items, tell them to keep the receipts all day long, ready to present at a moment’s notice.

5. The most effective method of prevention is a closed circuit video feed (CCTV), which monitors employee transactions from open to close. With the risk of being caught so high, employee theft becomes too dangerous to risk.