I'm looking to open a solo traditional 401k but can only fund it using after tax dollars since I'll be working as a contractor still getting a W2 and won't be generating an income from the business. I haven't been able to find anything online saying there's a form I fill out specifically for solo 401ks nor is there a clear answer if it's double taxed, and if there are ways I can avoid that. The obvious answer is to open a solo Roth 401k, but I'm trying to open it with Schwab since all my other investments are held under them.
