Spouse contributions to Solo 401k

[Jim P.]

I'm planning to set up a Solo 401K, but I'm having trouble finding information about married couples with Solo 401K's.  Should my wife and I have separate Solo 401K's?  Can one Solo 401K be shared between spouses (both contributing to the same account)?

I'm self-employed with no employees and my business will net about $100K this year.  My wife actively helps with the business, but I've never explicitly paid her with a W-2 or anything like that.  What's the best way to maximize the amount we can contribute to a Solo 401K?

[Mark Nolan]

@Jim P. 

With a solo 401k plan, each spouse can contribute $53,000 and each can contribute a catch-up amount of $6,000 if age 50 or older. Therefore, both spouses can supercharge their retirement savings by contributing a combined amount of $118,000.

If you are both owner-employees of the self-employed business sponsoring the solo 401k plan, both of you can participate in the same solo 401k plan. 

The following covers the self-employment rules. 

https://www.irs.gov/businesses/small-businesses-self-employed/self-employed-individuals-tax-center