When dealing with all plan assets, whether a bank account or title to real property, always use the Solo 401k Trust. Example:
If your 401k trust is named Johnson Software Trust, and your 401k is purchasing real estate, the purchase agreement should list Johnson Software Trust as buyer. If your 401k later sells this property, the purchase agreement should list Johnson Software Trust as seller. Your bank accounts and/or brokerage accounts should be in the name of Johnson Software Trust.
When supplying a Tax ID number for any 401k transactions (including the opening of a bank account), always supply the EIN (Employer Identification Number) assigned to your 401k trust – NOT the EIN for your business. This trust EIN can be found in your 401k plan documents on your Solo 401k dashboard.