Small business retirement plans come in a number of different shapes and sizes. Some are easy to set up and use, while others offer scalability and flexibility. Whether you’re a sole proprietor or have hundreds of employees, there’s a retirement plan to suit your specific needs. Here are the four main types:

Self-employed 401(k)

If you are self-employed and have no other employees, except for perhaps a spouse, a self-employed 401(k) may be right for you, especially if you never anticipate hiring other employees. Brokerage houses or financial institutions typically don’t charge you an initial setup or annual maintenance fee for a self-employed 401(k) account.

A self-employed 401(k) features generous contribution limits. You may contribute up to 25 percent of your eligible compensation, up to a maximum of $55,000 in 2018. You may also make up to $18,500 in salary deferrals ($24,500 if age 50 or older).

There are some administrative tasks related to self-employed 401(k)s that you need to pay attention to, though nothing too burdensome. For example, once your plan assets exceed $250,000, you must file an Annual Form 5500 with the IRS. You may also need to adjust your plan periodically for any legislative changes that may arise. Any withdrawals you take from them are subject to current federal income taxes and possibly to a 10 percent penalty if you are under 59½.

SEP IRA

For self-employed individuals or owners of small businesses, including those with employees, a SEP IRA might be your best option. A SEP (“self-employed pension”) IRA (“individual retirement account”) is easy to set up and maintain. As with self-employed 401(k)s, there’s usually no initial setup or annual maintenance fee for a SEP IRA.

With a SEP IRA, employers can contribute up to 25 percent of eligible employee compensation, up to a maximum of $55,000 in 2018. The employer must contribute the same percentage to employee accounts in years they contribute to their own account.

The administration of a SEP IRA is simple. Only employers can contribute to a SEP IRA plan, though you never have to file a Form 5500 with the IRS. You do need to notify employees of your employer contributions, if you make them.

Simple IRA

Companies with 100 employees or fewer, that do not have any other retirement plan, may find a Simple (Savings Incentive Match Plan for Employees) IRA best for their business. Some fees may be charged for opening and maintaining a Simple IRA, but these are usually low.

Both employers and employees can contribute to a Simple IRA, with the employer setting up a traditional IRA for each employee. Employers can either (1) match the first 3 percent deferred (match may be reduced to 1 percent in 2 out of 5 years) or (2) make a 2 percent non-elective contribution on behalf of all eligible employees. No additional business contribution may be made and the contribution may not exceed $12,500 for 2018.

Catch-up contributions of up to $3,000 (2018) available for those age 50 or older

No Form 5500 filing

Certain annual employee notifications

Withdrawals any time. If employee is under age 59½, withdrawals may be subject to a 25% penalty if taken within the first 2 years of beginning participation, and possibly to a 10% penalty if taken after that time period.

401(k) Plan

(better for larger companies given setup costs, administration, fiduciary responsibilities, etc.)

Employees are immediately 100 percent vested in any of the above retirement accounts, meaning they can take all funds with them if they leave work there. No matter your business entity—sole proprietor, partnership, S corporation, C corporation—a small business retirement plan can help you save for the future and can allow you to hire and retain good employees.