Free Tax Guide
What Income Sources Are Subject to California State Tax?
Key Takeaway
Four categories of income are subject to California state tax: (1) all worldwide income for CA residents; (2) California-source income for non-residents; (3) pass-through income from CA partnerships/S-corporations; and (4) retirement income based on residency status. The short version is that CA residents pay tax on all income earned anywhere. Non-residents pay only on CA-source income (wages from CA services, CA real estate, CA business). Residency determines the entire tax picture.1
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California income tax by residency status.
California taxes all income from every source — worldwide — for California residents. For nonresidents, California taxes only California-source income. California-source income includes wages earned in California, income from California businesses and partnerships, California real property income, and income from intangibles with a California business situs. For residents, out-of-state income, foreign income, and investment income are all subject to California tax regardless of where they arise. The resident vs. nonresident distinction depends on domicile and the length and purpose of California presence.
The Four Categories of CA-Taxable Income
ResidentsWorldwide IncomeNon-ResidentsCA-SourcePass-ThroughCA Partnership / S-CorpRetirementResidency-Based
| Category | CA Tax Treatment2 |
|---|---|
| Resident Worldwide | All sources taxed |
| Non-Resident CA-Source | Only CA-source |
| Pass-Through | CA apportionment rules |
| Retirement | Residency-based with exceptions |
Quick Reference
Jump to: resident, non-resident, pass-through, or retirement.
1. Residents: Worldwide Income
CA residents pay CA tax on all income.
If this is you: CA resident. All income — wages, investment, business, retirement — subject to CA tax. Credit for taxes paid to other states may apply.
Resident Income Strategy
- Report all income on CA return.
- Claim credit for taxes paid to other states.
- Apply federal conformity.
- Watch for CA-specific adjustments.
- Consider residency change for material savings.
2. Non-Residents: CA-Source Income
Non-residents pay only on CA-source income.
If this is you: Non-resident with CA income. Wages from CA services, CA real estate income, CA partnership/S-corp income all taxable. Form 540NR.
3. Pass-Through Entity Income
CA apportionment rules apply to pass-through income.
If this is you: CA partnership or S-corporation. Income apportioned using CA formula. Non-resident partners taxed on CA-source portion.
4. Retirement Income
Retirement income taxation varies by source and residency.
If this is you: Retired taxpayer. Pensions from CA employment typically CA-taxable for residents; non-residents get tax credits.
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CA Income Source Document Lookup
| Document | Purpose |
|---|---|
| Form 540 | Resident return |
| Form 540NR | Non-resident return |
| Schedule S | Other state tax credit |
| RTC §17041 | CA income tax imposition |
| FTB Publication 1100 | Out-of-state residents |
CA Income Tax Statute
- 4-year assessment statute.
- Unlimited for fraud.
CA Income Audit Patterns
| Situation | Audit Risk |
|---|---|
| Non-resident claiming no CA-source | Elevated |
| High-income resident | Moderate |
| Retirement income with CA ties | Variable |
CA Income Tax Escalation
Return Filed
Reviewed for CA-source completeness.
Audit Risk
Residency and source allocation reviewed.
Assessment
Additional tax on undisclosed CA-source income.
First 48 Hours of Income Sourcing
- Determine residency status.
- Identify CA-source income.
- Compute CA tax obligation.
- File Form 540 or 540NR.
- Engage counsel for complex sourcing.
★Brotman Law analyzes California income sourcing. Based in San Diego.
The ROI Question
Correct income sourcing prevents costly assessments. Professional analysis essential for multi-state high-income taxpayers.
If FTB is taxing income you earned in another state — or sent a notice about your income sourcing:
California income sourcing disputes are among the most contested areas in state tax — FTB’s position is often aggressive, and the rules for different income types differ significantly. A free 15-minute call covers whether FTB’s position on your income is legally supportable, and what a protest or response looks like.
Talk to Sam About Your CA Income Sourcing Issue — Free → Or call: (619) 378-3138
When to Engage
- Multi-state income.
- Non-resident with CA ties.
- Pass-through CA apportionment.
- Retirement sourcing.
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Frequently Asked Questions
What income is subject to California tax?
Residents pay CA tax on worldwide income. Non-residents pay on California-source income only. Four categories: resident worldwide, non-resident CA-source, pass-through entity income, and retirement income with residency-based rules.
What is California-source income?
Wages from services performed in CA, CA real estate income, CA partnership/S-corp income, CA business operations. Non-residents taxed on these even without CA residency.
Do CA residents pay tax on out-of-state income?
Yes. Residents pay CA tax on worldwide income. Credit for taxes paid to other states (Schedule S) prevents double taxation.
Does CA tax retirement income?
Residents pay CA tax on pensions. Non-residents generally not taxed on prior CA employment pensions (4 U.S.C. §114 federal statute). Specific analysis required.
What is Schedule S?
Other State Tax Credit. Used by CA residents to claim credit for taxes paid to other states on same income. Prevents double taxation.
Is Form 540 or 540NR correct?
Form 540 for CA residents. Form 540NR for non-residents and part-year residents. Residency status determines form.
Do non-residents file CA return?
Only if CA-source income exists. Even minimal CA-source income typically requires filing. Threshold depends on type and amount.
How is partnership income taxed?
CA apportionment using single-sales factor (post-2013). Non-resident partner’s share of CA-source partnership income taxable. Resident partner’s share fully taxable.
Are stock options CA-source income?
Varies. Option grant-to-exercise period location matters. Complex allocation for multi-state employment. Fact-specific.
Does CA tax capital gains?
Yes for residents on worldwide gains. Non-residents pay on CA real estate gains; financial asset gains generally not CA-sourced unless physical-presence work.
What is CA apportionment?
Formula dividing multi-state business income among states. CA uses single-sales factor. Market-based sourcing for services.
Can I avoid CA tax by moving?
Prospectively yes if residency actually changes. Retroactive CA tax on prior residency still applies. Careful documentation of move essential.
Does CA tax trust income?
Residency of beneficiary matters for some trusts. Non-California trusts with California beneficiary may have CA tax. Fact-intensive analysis.
Does California tax Social Security benefits?
No. California does not tax Social Security income. Unlike the federal government, which taxes up to 85% of benefits depending on income, California fully exempts Social Security benefits from state income tax. This applies to both residents and nonresidents receiving Social Security.
Are out-of-state municipal bonds taxable in California?
Yes. Interest on bonds issued by other states and their municipalities is taxable in California. Only interest on bonds issued by California state and local governments is exempt from California income tax. This is a significant difference from federal treatment, where all state municipal bond interest is exempt from federal tax.
Are US Treasury bonds and federal obligations taxable in California?
No. Interest income from U.S. government obligations — including Treasury bills, notes, bonds, and savings bonds — is exempt from California income tax under federal statute (31 U.S.C. § 3124). California must follow federal law on this exemption. However, federal obligations are subject to federal income tax.
Do I have to pay California income tax if I live out of state?
Only on California-source income. Nonresidents owe California income tax on wages for services performed in California, income from California businesses and partnerships, California real property income, and certain intangible income with a California business situs. If you have no California-source income, you have no California filing requirement — regardless of whether you were once a California resident.
Are unemployment benefits taxable in California?
No. California does not tax unemployment compensation. This is a significant difference from federal treatment — the federal government taxes unemployment benefits as ordinary income. California residents who receive unemployment must include it in federal gross income but exclude it from California gross income when filing Form 540.
Are RSUs and stock options taxable in California for nonresidents?
Yes, in part. California taxes the California-source portion of RSU and stock option income for nonresidents — the portion attributable to services performed in California during the vesting or option period. The FTB applies an apportionment formula: California workdays during the relevant period divided by total workdays. Former California employees receiving RSU or option income years after leaving California may still owe California tax on a prorated share.
What is FTB Publication 1100?
FTB Publication 1100 (“Taxation of Nonresidents and Individuals Who Change Residency”) is the FTB’s official guide to California income sourcing for nonresidents and part-year residents. It covers how the FTB determines California-source income for each income category, how to apportion income when you move into or out of California during the year, and how to complete Schedule CA (540NR). It is the primary reference document for nonresident California tax analysis.
Next Steps
Income sourcing? 15-min consultation free.
- CA income tax: RTC §17041 et seq.
- Sourcing rules from FTB Publication 1100.
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