SEP IRA Versus Solo 401(k): Which is Best For You?

sep-ira-vs-solo-401kSelf-employed persons have two options when it comes to establishing a retirement account. If you are self-employed and you want to save for retirement, two of your primary options will be a SEP IRA or a Solo 401K. The SEP IRA is a super-charged IRA account that runs off of IRA rules while the Solo 401(K) is an employed based retirement plan used solely for the business owner(s) when they have no other employees.

Both a SEP IRA and a Solo 401(k) can be self-directed and invested into real estate, private company stock, or precious metals. Under a SEP IRA, you will have a self-directed IRA custodian. Under a Solo 401K, you can serve as your own trustee and administrator or you could use a custodian.

While a SEP IRA and a 401(k) can be used by business owners with employees other than the business owners, this article compares the two account options for those who are self-employed with no other employees other than themselves (and partners and family).


SEP IRA Solo 401K
Contribution Max $53,000 max annual contribution (it takes $265K of self-employment income to max out). Contributions are all employer contributions. $53,000 max annual contribution (it takes $140K of wage/se income to max out). Contributions are employee and employer.  Because a solo K is easier to max out each year on less income, it gives greater opportunity for utilization over the SEP IRA.
Traditional & Roth All SEP contributions are traditional dollars and all funds in a SEP must be traditional dollars. SEP IRA funds can be converted to a Roth IRA though. A solo 401(k) can have a traditional account and a roth account within the same plan. You can convert traditional sums over to Roth as well. Because you can have Roth accounts and Traditional account in the 401K, that provides more options in the solo 401(k).
Contribution & Establishment Deadline Date of the company tax return INCLUDING extensions. You may also establish a new SEP IRA at the time you make the first contributions even if that is for the prior tax year. For people making contributions for the first time for a prior year (e.g. in April of 2015 for 2014 contributions), this is a big benefit as a 401K) cannot be used unless it was set up in the tax year of the contribution. Date of the company tax return INCLUDING extensions. However, for new plans, they must be established by December 31 of the year you are seeking to make contributions. This means you have to plan ahead and establish the 401(k) before the end of the year.
Custodian Requirement An IRA must have a third party custodian involved on the account (e.g. bank. Credit union, trust company) who is the trustee of the IRA. A 401(k) can be self trustee, meaning the business owner can be the trustee of the 401(k). This provides for greater control but also greater responsibility.
Investment Details A SEP IRA is invested through the self directed IRA custodian. A SEP IRA can be subject to a tax called UDFI/UBIT on income from debt leveraged real estate. A Solo 401(k) is invested by the trustee of the 401(k) which could be the business owner. A solo 401(k) is exempt from UDFI/UBIT on income from debt leveraged real estate.


In sum, there are many differences between a solo 401(K) and a SEP IRA but the solo 401(k) has proven to be an excellent tool that provides greater flexibility when saving and investing for retirement.