A plan administrator is a person or entity that manages employee plans at behest of the employer. A good example of a plan administrator would be a company that offers 401ks. The employer and employee would both have a relationship with this company. The plan administrator will have their own EIN, because they are a separate entity. But that doesn’t mean the plans themselves will fall under that EIN. Rather, 401ks have their own EIN, to separate it from the business and the employee.
The plan administrator is the person who will set up the EIN for the accounts that are under them, and the EIN will be referenced on the documents for the accounts. The actual employee doesn’t need to worry about the EIN for the plan, though they may need to log it for information during tax time. Understanding which accounts require tax IDs and why can be important for managing taxes and finances, and it’s something that the plan administrator can discuss with the employee. Unlike employer plans, independent retirement accounts (such as IRAs) usually don’t need EINs, though there are some rare situations in which they do.