The equity is irrelevant.Hiring a part-time employee is another option.

The second criteria you must meet is that you can not have full time employees (over 1,000/yr) work for you in any business that you own.If you qualify - you can set up truly self-directed Solo 401k plan.

I am the only employee

I was a licensed employee broker in both Colorado and California DECADES ago.

For example, perhaps you cannot access your employee deferrals, but can roll out other accounts while employed?

The licensed listing agent (an employee of the Cook County Land Bank, IL) violated many rules licensed agents everywhere adhere to.

Learn more here:https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-prohibited-transactionsHope this helps!

The government employment center is a huge factor in this with something like 40,000 government employees.

You could setup your own 401k plan with a company you setup and rollover the funds into that 401k, provided you both are employees of that company, but the funds would still be separate accounts within the 401k. 

I’ve been fortunate and blessed to have been employed by a company who has employee stock options over the last 10+ years.