A series does not need an Employer Identification Number (EIN), unless any of the following are true:

• the series has W2 employees,
• the series will elect to be taxed like a corporation,
• the series will have a different tax classification than the Series LLC,
• the series will be taxed like a partnership (i.e., has multiple owners), and your CPA wants to file separate returns for each series rather than a combined return for the LLC and all of its series (see more below); or
• the series has excise tax obligations (excise taxes are commonly levied on cigarettes, alcoholic beverages, soda, gasoline, insurance premiums, amusement activities, and betting).

Another reason a series might need an EIN is if your bank requires one. Banks will want to see an EIN when setting up a bank account. For more on this topic, see our article titled "Does each series need a separate bank account?".