Credit card for my Solo 401k plan

Now that I set up my Solo 401k, can I get a credit card for my plan to pay for the investment related expenses and to earn rewards?

Answer:

No. If the bank offers a credit card for your Solo 401k Trust, then you personally will be required to sign the guarantee. You are not allowed to extend any credit to the plan since you are considered a "Disqualified Person" with respect to your 401k. If you did so, it would constitute a "Prohibited Transaction," and your plan would be deemed disqualified. 

Be sure to review the Prohibited Transaction section to ensure that you have good understanding of it. As a fiduciary of the plan, it is your responsibility to avoid any prohibited transactions.