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County of Sonoma California
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Regulatory Guide – Business & Tax Reporting Requirements


Use this guide for becoming acquainted with the basic tax and license requirements for starting and operating a business. Basic filing requirements, deadlines, and key forms for appropriate agencies are included, but you should not depend on this guide as the only source for sole proprietorship and general partnership business structures. Contact all appropriate agencies directly for current and specific information on taxes and licenses. Limited partnerships, corporations, and limited liability companies should contact professionals such as lawyers and accountants for filing and reporting.

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Start-Up Forms

To start a business, the following forms are generally required:


  • IRS Businesses with Employees:
  • SS4: Application for Federal Employer (EIN)
  • W-4: Employee Withholding Allowance Certificate
  • I-9: Employee eligibility verification
    (resident status for Immigration and Naturalization Services INS)
  • W-5: Advanced Earned Income Credit

State of California

  • DE-1: Registration for new businesses with employees
  • Employment Development Department (EDD)
  • BT-400: Sales of tangible personal property:
  • Sales and Use Tax, Initial Registration Form
  • State Board of Equalization

County of Sonoma

  • Fictitious Business Name Statement
  • PRMD


  • Business license or tax permit in each city where you conduct business

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Calendar of Reporting Deadlines

The following forms must be filed with federal, state and local governments on a one-time, quarterly, or annual basis:

  • One Time Federal: SS-4 W-4
  • One Time State: DE-1 BT400
  • Quarterly Federal: 1040ES 8109B-FIT 8109B FICA 8109B-FUTA 941
  • Quarterly State : BT401* (See notes about BT401.) 540ES DE-6 DE-88
  • Annual Federal: W-2, W-2P, W3, 940, 1040, Schedule C,
  • Schedule. SE, 1065, Schedule. K-1,
  • Transmittal Form 1096 and Forms 1099, I-9
  • Annual State: W2, W-2P, DE7, 565, 1099-R
  • Annual Local: City Business Licenses/Tax Certificate, Fictitious Business Name Statement** (See notes.)
  • Annual Business Property Tax Statement 571-L is required
  • Firms with agricultural employees are required to file Form 943 “Employer’s Annual Tax Return for Agricultural Employees” annually.

* Depending on the size of your business, you may have to file these forms monthly, annually, or quarterly.

** This form must be refiled every five years.

Electronic Payment Options

Federal and state taxes can be paid by the Electronic Federal Tax Payment System (EFTPS). To enroll, employers can call (800) 945-8400 or (800) 555-4477. Even if an employer is not required to use this method, most find it easy and choose this filing method.

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Federal, State and Local Forms

Brief Description of Forms


  • I-9 Employee eligibility verification (resident status), Immigration and Naturalization Service (INS)
  • SS-4 Application for Federal Employer (EIN), Internal Revenue Service
  • W2 Wage and Tax Statement, IRS
  • W3 Transmittal of Wage and Tax Statements, IRS
  • W4 Employee Withholding Allowance Certificate, IRS
  • W5 Advanced Earned Income Credit, IRS
  • 940. Employer’s Annual Federal Unemployment Tax Return (FUTA), IRS
  • 941. Employer’s Quarterly Federal Tax Return, IRS
  • 1065. US Partnership Return of Income, IRS
  • 1066. Annual Summary and Transmittal of US Information Returns, IRS
  • 1067. Miscellaneous Income, IRS
  • 8109B Federal Tax Deposit Coupon IRS
  • 1040ES Estimated Tax For Individuals, IRS
  • Schedule C Profit of Loss Form, IRS
  • Schedule SE Self Employment Tax, IRS


  • BT400 Sales and Use Tax, Initial Registration Form, State Board of Equalization
  • BT 401 California sales and use tax, Periodic Reporting Form, State Board of Equalization
  • DE1378 Elective Disability Insurance, for business owner (optional), EDD
  • DE1378DI Application for DI Elective Coverage, EDD
  • DE4 CA Employee Withholding Allowance Certificate (may use IRS Form W-4 in lieu of this form), EDD
  • DE4P Withholding certificate for pension or annuity payments (may use IRS Form W-4P in lieu), EDD
  • DE6 Quarterly Wage and Withholding Report, EDD
  • DE7 Annual Reconciliation Statement, EDD
  • DE34 Report of New Employees
  • DE88 Payroll Tax deposit, EDD
  • LP-1 Certificate of Limited Partnership, Secretary of State
  • 540 Profit from business, sole proprietor, Franchise Tax Board
  • 540ES Income tax deposits, Franchise Tax Board
  • 565 To report miscellaneous income, State Franchise Tax Board (Send with Federal 1099)


  • City business licenses/tax certificate. Generally required for each incorporated city in which you do business (every year)
  • Fictitious Business Name Statement. Office of the Sonoma County Clerk. Must be filed at least every 5 years.

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