401(k) Plan
A 401(k) plan is an employer-sponsored, tax-advantaged retirement savings plan. These plans fund with pre-tax employee- (and often matching employer-) contributions. Then, the accounts grow tax-free until withdrawal. 401(k) plans often provide employees with a choice of investment options--typically mutual funds.
403(b) Plan
A 403(b) plan is a tax-advantaged retirement savings program. It is available to employees of public education organizations, certain non-profits, and some self-employed ministers. Employees make pre-tax salary deferrals into the plan. These contributions grow tax-deferred until withdrawal.
457 Plan
The 457 Plan is a non-qualified, tax-advantaged, deferred-compensation retirement program. It is available for governmental and some tax-exempt non-governmental organizations. The employer sponsors the plan and the employee defers compensation into it on a pretax or after-tax (Roth) basis. This plan operates similarly to 401(k) and 403(b) plans. However, a key difference is that—unlike those plans—it has no 10% penalty for withdrawal before the age of 55. Still, the withdrawal remains subject to ordinary income taxation.
Qualified Retirement Plan
A qualified retirement plan is an employer-sponsored plan that meets the requirements of Section 401(a) of the Internal Revenue Code. Thus, such plans are eligible for certain Internal Revenue Service (IRS) tax benefits. Examples of qualified retirement plans include 401(k), 403(b), and profit-sharing plans.