The Employee Retirement Income Security Act (ERISA) is federal legislation that allows government officials to maintain oversight over different employee-administered welfare plans and benefits. Some of the programs that federal officials oversee include health insurance policies and pensions. ERISA only covers two types of retirement plans, including defined contribution and benefit ones.
Administrators of defined contribution plans, including 401(k)s, employee stock ownership, 403(b) and profit-sharing ones, generally don't promise employees any specified benefit amount when they retire. Employers may contribute a certain percentage to complement what an employee invests into such an account, though. Employers generally take pre-tax deductions from their employee's pay and invest those funds into the retirement account on their worker's behalf.