Harper Tax CPA

Converting to an S Corporation in California: A Practical Guide (2025)

Thinking about switching your business to an S corporation (“S-corp”)? This can be an excellent move for many California entrepreneurs—especially once net profit grows beyond what a sole proprietorship or single-member LLC can efficiently shelter through self-employment tax planning.

This guide from Harper Tax CPA explains, using only official sources, how California taxes S-corps, how to make the federal S-election properly, what “reasonable compensation” really means under IRS guidance, and why California professionals often must use a Professional Corporation (PC) instead of a standard LLC.

What You’ll Learn

  • The 1.5 % California S-Corp tax, the $800 minimum franchise tax, and the first-year waiver.
  • How and when to file your IRS Form 2553 S-election—and what happens if you miss the deadline.
  • How the IRS defines “reasonable compensation” for shareholder-employees.
  • California’s restrictions on LLCs for licensed professions.
  • Which return to file (Form 100-S) and when payments are due.
  • How the Pass-Through Entity Elective Tax (PTET) can restore part of your federal SALT deduction.

How California Taxes S-Corporations

At the federal level, an S-corp is a corporation (or eligible LLC) that elects Subchapter S treatment under the Internal Revenue Code. Income generally “passes through” to shareholders, avoiding double taxation.
However, California does not fully follow federal treatment—the state imposes its own 1.5 % tax on S-corp net income and an annual $800 minimum franchise tax.

According to the Franchise Tax Board (FTB):

“We tax every S corporation that has California source income 1.5 %. Your minimum franchise tax ($800) is due the first quarter of each accounting period. We waive the minimum tax on newly formed or qualified S corporations filing an initial return for their first taxable year.”
— FTB S Corporations

That means a new corporation formed in 2025 owes no minimum tax in its first taxable year, though profits remain subject to the 1.5 % entity-level tax. After year 1, the $800 minimum applies annually even if the business has a loss.

The FTB’s Business Tax Rates chart confirms the 1.5 % rate for S-corps.
👉 FTB Business Tax Rates

S-corps operating in and out of state must apportion income to California using Schedule R, included with Form 100-S.

How California Recognizes the Federal S-Election

California automatically honors the federal S-election. Once the IRS accepts Form 2553, California treats the entity as an S-Corp and requires filing Form 100-S.
👉 California Tax Service Center – S Corporations

That applies whether you formed a traditional corporation or an LLC that elected corporate treatment. An LLC taxed as an S-corporation for federal purposes files Form 100-S just like a standard corporation.

The Form 100-S instructions state:

“All federal S corporations subject to California laws must file Form 100-S and pay the greater of the minimum franchise tax or the 1.5 % income or franchise tax.”
— FTB Form 100-S Booklet (2024)

Step-by-Step: Making the S-Election

1. Form Your Entity

  • Corporation route: Form a California corporation with the Secretary of State and then file Form 2553 with the IRS.
  • LLC route: An LLC can also make an S-election. If filed timely, Form 2553 alone is sufficient to be treated as a corporation and S-Corp under federal rules (Treas. Reg. § 301.7701-3(c)(1)(v)(C)). You do not always need a separate Form 8832. California then treats this LLC as an S-corporation and requires Form 100-S.

👉 IRS Form 2553 Instructions (PDF)

2. File Form 2553 on Time

For calendar-year taxpayers, the filing deadline is March 15 of the year you want S-status (the 15th day of the 3rd month).
If you missed it, you may qualify for late-election relief under Revenue Procedure 2013-30. The IRS provides step-by-step instructions and examples.
👉 IRS Rev. Proc. 2013-30 Guidance

3. Register for Payroll in California

Because S-Corp shareholder-employees must receive wages for their services, your corporation becomes a California employer. You must:

  • Register with the Employment Development Department (EDD) within 15 days of paying wages.
  • Withhold and remit payroll taxes (state income tax, SDI, and UI/ETT).
  • Report new hires within 20 days of the employee’s start date.

👉 EDD – Employer Registration
👉 EDD – New Hire Reporting

4. File and Pay California Taxes

  • File Form 100-S by the 15th day of the 3rd month after year-end (March 15 for calendar-year filers).
  • Pay the greater of $800 or 1.5 % of net income.
  • Corporations must make estimated payments during the year when the total tax exceeds $500.

5. Consider the Pass-Through Entity Elective Tax (PTET)

California allows certain pass-through entities, including S-corporations, to elect an optional entity-level tax that owners can claim as a credit on their personal returns. This can restore part of the federal SALT deduction lost under the 2017 TCJA.

Key forms:

  • FTB 3804 – Computation of PTE Tax
  • FTB 3893 – Payment Vouchers
  • FTB 3804-CR – Owner Credit

👉 FTB PTET Overview & Forms

Elections and payments must be timely: typically a first payment by June 15 of the taxable year and final payment by the original due date of the return.

Reasonable Compensation: What the IRS Expects

The IRS closely scrutinizes how S-Corp shareholder-employees pay themselves. You must pay a reasonable salary (W-2 wages) before taking non-wage distributions.

Official IRS sources explain:

“S corporations must pay reasonable compensation to a shareholder-employee in return for services that the employee provides to the corporation before non-wage distributions may be made.”
— IRS – S Corporation Compensation and Medical Insurance Issues

The IRS lists key factors:

  • Duties and responsibilities
  • Training and experience
  • Time devoted to the business
  • Comparable wages for similar roles
  • The company’s dividend history and profitability

The IRS Fact Sheet FS-2008-25 and the Reasonable Compensation Job Aid (used by IRS examiners) provide detailed analysis frameworks.
👉 IRS Fact Sheet FS-2008-25 (PDF)

Practical steps:

  1. Benchmark salary data (e.g., labor statistics or job postings).
  2. Document your reasoning.
  3. Pay wages through payroll with withholding and payroll tax deposits.

Maintaining documentation protects you during audits and supports the wage deduction.

Professional Services and Entity Restrictions in California

Unlike many states, California restricts professional services from operating through standard LLCs.
Under California Corporations Code § 17701.04(e):

“Nothing in this title shall be construed to authorize a domestic or foreign limited liability company to render professional services, as defined in Section 13401.”

“Professional services” include law, medicine, accounting, architecture, and engineering (Corp. Code § 13401(a)).
👉 Cal. Corp. Code § 17701.04
👉 Cal. Corp. Code § 13401

Therefore, licensed professionals must generally form a Professional Corporation (PC) or, in some fields, a Registered LLP.
Professional corporations file ARTS-PC with the Secretary of State and are subject to the same FTB $800 minimum tax and 1.5 % S-Corp rate once electing S-status.
👉 CA Secretary of State – ARTS-PC Form

Should You Convert Now?

Here’s how to think through the S-corp crossover point:

  1. Entity-level taxes — 1.5 % of profit plus $800 minimum.
  2. Payroll overhead — software, payroll service, EDD compliance.
  3. Reasonable salary — must be paid regardless of profit volatility.
  4. PTET election — can offset state taxes for high-income owners.

S-corp status tends to help once your profit after owner wages exceeds roughly what you’d otherwise pay self-employment tax on (around $60k+ profit for many). However, the right threshold varies by case. At Harper Tax CPA, we model each scenario with state taxes, payroll, and PTET factored in.

Implementation Checklist (California-Ready)

Step

Action

Source

1

Form a CA corporation or PC; obtain EIN

CA Secretary of State

2

File Form 2553 by deadline or apply for late relief

IRS Form 2553 Instructions

3

Register for payroll within 15 days of paying wages

EDD – Employer Registration

4

Report new hires within 20 days

EDD – New Hire Reporting

5

File Form 100-S; pay 1.5 % + $800 minimum

FTB Form 100-S Instructions

6

Consider PTET election (FTB 3804/3893/3804-CR)

FTB PTET Page

7

Document reasonable compensation

IRS Fact Sheet FS-2008-25

Frequently Asked Questions (California S-Corps)

1. What is California’s S-corp tax?
1.5 % of net income or $800 minimum, whichever is greater. (FTB)

2. Does California recognize my federal S-election automatically?
Yes, per the California Tax Service Center.

3. Can an LLC be taxed as an S-corp?
Yes—file Form 2553 timely; no separate Form 8832 needed if deemed election applies (IRS regs).

4. Do licensed professionals need a Professional Corporation?
Yes. California prohibits professional services LLCs (Corp. Code § 17701.04(e)).

5. When is Form 2553 due?
By March 15 for calendar-year taxpayers; relief available under Rev. Proc. 2013-30.

6. What is “reasonable compensation”?
A market-based wage for your duties, paid via W-2, per IRS guidance.

7. When must I register with EDD?
Within 15 days of paying wages; also file new-hire reports within 20 days.

8. Which return do I file?
Form 100-S by March 15 for calendar-year filers (FTB).

9. What is the PTET election?
An elective tax letting S-corps pay California tax on behalf of owners (FTB 3804 series).

10. Do QSubs exist in California?
Yes—California follows federal QSub rules; the parent S-corp pays the $800 annual tax (CA Tax Service Center).

How Harper Tax CPA Helps California Businesses

  • Entity & Election Setup – We handle CA PC formations, Form 2553, and Rev. Proc. 2013-30 relief filings.
  • Reasonable Compensation Planning – Market-based comp analysis aligned with IRS expectations.
  • Payroll & EDD Compliance – Full setup, new-hire reporting, and payroll integration.
  • California Tax Planning – Form 100-S preparation, estimates, PTET modeling, and multi-state apportionment.

 

Get Started

Ready to make your S-Corporation more efficient?

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Verified Source List (for reader reference)

  1. FTB S Corporations
  2. FTB Business Tax Rates
  3. FTB Form 100-S Instructions (2024)
  4. CA Tax Service Center – S Corporations
  5. IRS – S Corporation Employees, Shareholders & Officers
  6. IRS Fact Sheet FS-2008-25
  7. IRS – S Corporation Compensation and Medical Insurance Issues
  8. IRS Form 2553 Instructions
  9. IRS Rev. Proc. 2013-30
  10. EDD – Employer Registration
  11. EDD – New Hire Reporting
  12. CA Corporations Code § 17701.04
  13. CA Corporations Code § 13401
  14. CA Secretary of State – ARTS-PC Form
  15. FTB PTET Program