Considering how big and complex the IRC is, it may be surprising to learn that there are no IRS rules or regulations that directly relate to how you should title or name your Solo 401(k) plan. In general, the common practice is to include some variation of the business name that adopted the plan with any of the following words or terms: 401(k) plan or 401(k), Solo 401(k), Individual 401(k) or IK plan, or Self-Employed 401(k).
For example, for ABC Corporation, the plan name could be the ABC Corporation Solo 401(k) plan, the ABC Corporation 401(k) plan, the ABC Corporation Individual 401(k) plan, the ABC Corporation Self-Employed 401(k) plan, or ABC Corporation IK plan. In other words, there is no right or wrong way to name your plan. It is a good idea from a banking and investment perspective, however, to have some reference to the fact that the account is associated with a tax-exempt retirement plan.