I invested my Solo 401k funds in notes. When the interest payments are made, should I deposit the payments into my Roth IRA? Is it correct that I cannot deposit more than the limit of $6,500? After the interest payments add up to $6,500, should I send the interest payments elsewhere?
First of all, all gains and profits from investing funds from the Solo 401k plan must be deposited back into the Solo 401k. If the Solo 401k plan paid for and now owns the notes, you cannot send the interest payment to any other account, even if it is your IRA. Plus, you cannot transfer funds from a regular Solo 401k account to a Roth IRA. The first only accepts pre-tax amount, while the latter takes after-tax amount only.
If your Solo 401k account owns notes and receives interest payments, all interest should be deposited into the plan. The limit you mention is contribution limit, which is different from investment earnings. Every year, you can only deposit a maximum of $6,500 into an IRA, and $54,000 into a Solo 401k account. However, once these contributions are in the plan and earning interest, there is no limit on how much interest can be deposited. In fact, all interest amounts have to be deposited back into the Solo 401k.