This research is the first to empirically analyse the characteristics of firms that defer the social security contribution for their employees to the Vietnam Social Security Agency, which is a chargeable offense starting 2018 as the Vietnam government focuses on ensuring worker welfare. Using data on 873 public firms headquartered in four major cities (Ha Noi, Ho Chi Minh, Da Nang, and Hai Phong), we find that non-state-owned firms and firms with lower profitability and higher debts are more likely to be in arrears on social security contribution. On the other hand, the roles of foreign ownership, size, number of employees, and number of branches/offices are insignificant. We further show that being social security contribution indebted would negatively affect shareholders’ interest as it is associated with lower firm market values.