California - Business Entity Identifying Number

California has three identifying numbers for business returns.

  • California Corporation Number is an eight-digit number beginning with C. In TaxAct, enter the seven digits following the C.
  • Secretary of State (SOS) Number is a 12-digit number beginning with 19 or 20.
  • LLC Temp Number is a none-digit number.

Visit the California Secretary of State website to determine your entity's California ID number and type.

Special Circumstances

California Corporation Number starting with 4: In March of 2017, the California Secretary of State began issuing California Corporation Numbers that begin with a 4. The California electronic filing schema doesn’t allow for returns for 2014, 2015, or 2016 to be e-filed if the California Corporation Number begins with anything other than C. If your number starts with 4, and you need to file a return for any of those years, it must be paper filed.

Returns with a California Corporation Number beginning with 4 may be electronically filed for 2017 and years after.

If the California Franchise Tax Board states requires that you e-file but you have a number that begins with 4, you need to file a Business Entity e-file Waiver Request and indicate you cannot file electronically due to technology constraints. For additional questions, contact your account manager or an e-file coordinator at