From the article:
An employee stock ownership plan (ESOP) is a qualified retirement plan which is designed to hold stock of the company which sponsors the plan as its primary asset for the benefit of the company’s employees. According to the ESOP Association, there are over 11,500 employee-owned companies in the United States covering approximately 10 million employees with more than $600 billion in employee asset value. The significant majority of these companies are closely held, privately owned businesses that formed an ESOP as a vehicle for ownership succession, as opposed to public companies that implement employee-ownership programs as a pure employee benefit and retention tool. Although ESOPs have been around for decades, favorable tax laws and numerous success stories have increased their popularity.