401(k) retirement plan is an employment, tax- advantaged, benefits program. The plan carries a defined contribution from both the employer and the employee. It is not an investment. It is a type of account that has special benefits that allow you to build wealth by investing in employer-determined plan assets such as mutual funds, stocks, index funds, and real estate investment trusts.

There are several different types of 401(k) plans, each with unique advantages and drawbacks ranging from tax rules to bankruptcy protection. Some of these plans include the traditional 401(k), a self-directed plan, a safe-harbor plan, a SIMPLE 401(k), Roth 401(k), and the tiered-profit sharing plan structure.

If you work for a government agency or non-profit, you will not be eligible for a 401(k) account. Instead, you might have something known as a 403(b) plan.