When you file California business tax returns, the California Franchise Tax Board requires that you put your filing number on the tax forms. The filing number is not your company's tax identification number. It is a separate number that was assigned by the California Secretary of State when you registered with that office. If you don't know the filing number, there are a couple of ways to look it up.
Find any receipt or paperwork from the California Secretary of State pertaining to your business.
Look for a 12-digit number that begins with the year your organization was registered with the Secretary of State. For example, if your business was registered in 2006, look for a number that begins with 2006. This is your filing number.
Call or e-mail the Secretary of State's office to request the filing number for your company. Include your full name, the company's name, its address and tax identification number. The office staff will look up the number and give it to you.