If you have no common law employees, those that are not spouses, owners or partners, the best plan is the Individual (k), which permits the highest aggregate percentage of contributions and flexibility in defined contribution plans. The administration is straightforward and self-directed: you are the trustee, custodian and administrator, unlike any IRA plans. The SEP-IRA is also a common and easy plan for employers, but percentage limitations on contributions, and lack of flexibility makes it less favorable, overall. The SIMPLE IRA is a small form of a plan allowing employee deferral, but limits the amount of contribution. The SIMPLE can be a good plan for those who have lower income. These employer based IRAs must always have a trustee or custodian as permitted by the IRS code, and may not be self-trusteed. These plans do not provide features of the qualified plan, such as being able to borrow from the IRA, and in some states are not creditor proof, among other things, The defined benefit plan has even higher contribution levels depending on your age and retirement criteria. These are expensive plans to administer, but under the right circumstances are excellent plans for people who have the money to contribute, and are late in making the decisions to start making retirement contributions. In all cases, you may always make contributions to IRAs if you have received compensation as outlined by the IRS.