A profit-sharing plan is a defined contribution plan in which the company agrees to make substantial and recurring though generally discretionary contributions. This means the employer decides how much or how little to contribute each year, based on the profitability of the company.
A money purchase plan is a defined contribution plan where the employer is required to make an annual contribution on behalf of all eligible employees, regardless of the profitability of the company.
A Savings Incentive Match Plan for Employees (SIMPLE) allows employees to make pretax salary deferrals and requires employers to make matching contributions into the 401(k) plan.
A 401(k) plan is a type of retirement plan where both the employee and the employer have an opportunity to make contributions. No federal income taxes are paid on pretax contributions going into the plan, and all the money in the plan has the potential to earn tax-deferred earnings. Some plans allow for Roth 401(k) contributions, which are contributions made on a post-tax basis but may have tax-free earnings when distributed if certain conditions are met.