This is really interesting. I'd considered a solo 401k at one point because a made a small amount of self-employment income in one year, but decided against it because it wasn't enough to be worth the hassle, and I didn't expect to keep having self-employment income. Now I wish I had gone through it, just so I'd have a place to roll over this old 401k. (Of course, now that I look, Vanguard doesn't do solo 401ks anymore and redirects to Ascensus, so might just be frying pan to fire anyway.)

> now that I look, Vanguard doesn't do solo 401ks anymore

Vanguard wouldn't need to know it was a solo 401k, they would just see a trust being signed up. There are other institutions that you can go into mutual funds or get similar exposure from who are more acclimated to solo 401k entities though.