When e-filing a business tax extension, should I provide my SSN or EIN?

If you file a separate tax return for your business and you’re required to provide the business’ EIN (employer identification number) on the return, you should also provide the EIN on your tax extension request. Note that most businesses are required to obtain an EIN, which the IRS uses to identify a business entity. However, if you have a single-member LLC — which is considered a “pass-through entity” (or “disregarded entity”) — you should use your SSN (Social Security Number) instead of an EIN. Pass-through entities are reported as part of the owner’s personal tax return, which means you only need one (1) personal tax extension (IRS Form 4868) to cover both yourself and your business.