These plans are appealing if you intend to sock away large sums - you can contribute up to $53,000 in 2016. But 401(k) plans require more paperwork than SEP IRAs. If your account balance exceeds a certain amount, you have to file a special tax return for the plan, which can add slightly to tax-preparation costs and hassles.
In addition, some of the firms that will help you set up a solo 401(k) account levy setup charges (typically $100 to $375, depending on the level of service and the size of your account) as well as annual fees of up to $400.
