The individual or solo 401(k) plan lets you sock away much greater amounts for retirement at a smaller salary base. It has two parts: One is the employee salary deferral. The other is an employer profit-sharing contribution. Since self-employed people are both employer and employee, they're eligible for both parts.
In 2015 you can park up to $18,000 (plus $6,000 if you're 50 and older) in addition to 20 percent of your compensation, up to a total limit of $53,000 (or $59,000 if you're over 50).
Let's say you earn $150,000 and are over 50. You can contribute $24,000 through the salary deferral portion. Then you can set aside 20 percent (or 25 percent if you are incorporated) of your salary minus your 401(k) contributions and self-employment tax, which amounts to about $8,900. In this example, you would be able to contribute a total of about $47,000.
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"If you're self-employed and have no employees, I really like the solo [IRA] because it's flexible," said Alex Mojica, a wealth management strategist with Zions Bancorporation.