California Nonconformity to Federal Retirement Rules

California sets its conformity date by statute, currently January 1, 2015, and then enacts selective updates. The result is a tax code that resembles the federal code in broad outline but diverges meaningfully in retirement-relevant areas. For a high-earner California resident the nonconformity issues add up to real money. Below are the rules that most often surprise transplants from no-tax or full-conformity states.

Health savings accounts: fully taxable

California does not conform to Internal Revenue Code §223. For California income tax purposes:

• HSA contributions are not deductible from California taxable income.
• HSA earnings (interest, dividends, capital gains within the account) are taxable annually on the California return.
• Qualified medical distributions are tax-free for both federal and California purposes.

Practical effect: a Californian in the 9.3% bracket loses approximately $400 per year on a maxed family HSA ($8,550) versus a resident of a conforming state. The HSA still wins on a federal-only basis, but the after-state-tax internal rate of return is materially lower.

Mental Health Services Tax (Proposition 63)

Cal. Rev. & Tax Code §17043 imposes a 1% surtax on California taxable income exceeding $1,000,000. The threshold is not indexed for inflation and applies to all income, including retirement-plan distributions and Roth conversions. Combined with the top regular rate of 12.3%, the marginal California rate at high incomes is 13.3% — the highest state rate in the United States.

Roth conversions and lump-sum distributions

California taxes Roth conversion income in the year of conversion at full marginal rates. There is no state-level §1411 Net Investment Income Tax, but conversions can trigger the 1% mental health surtax. California also does not recognize the federal §402(d) 10-year averaging election for lump-sum distributions (repealed federally for most filers but preserved for those born before 1936); residents who relied on it before moving to California should expect different treatment.

Pension source-tax shield

Federal Public Law 104-95 (4 U.S.C. §114) prohibits states from taxing the retirement income of nonresidents based on services performed while a resident. A Californian who moves to Nevada in retirement is immune from California tax on subsequent IRA, 401(k), and pension distributions — even though contributions were made while resident in California. This is the strongest argument for pre-retirement domicile change for California residents holding large traditional balances.

OBBBA conformity status

California has historically taken multi-year intervals to enact federal conformity bills. As of 2025 California has not conformed to:

• The OBBBA permanent $15M federal estate exemption (no California estate tax to begin with, so largely moot).
• OBBBA's permanent 100% bonus depreciation under §168(k) — California still allows only state-law depreciation methods.
• OBBBA's permanent §199A QBI deduction — California does not allow QBI.
• The $40,000 SALT cap. California has its own elective pass-through entity tax (Cal. Rev. & Tax Code §§19900–19906) to work around the federal cap — still in effect and now valuable as a permanent OBBBA feature.

State-level retirement-account exemptions from creditors

California is a debtor-favored state for retirement accounts. Cal. Code Civ. Proc. §704.115 exempts ERISA-qualified plans without limit and IRAs to the extent "necessary for the support of the judgment debtor when the debtor retires" — a fact-specific inquiry that has produced inconsistent case law. For high-balance IRAs, California's creditor protection is materially weaker than Texas, Florida, or Nevada.

Worked example: HSA over 20 years

A California family contributes $8,550 annually to an HSA for 20 years and earns 7% annually. Federal: balance grows to approximately $375,000 tax-deferred; tax-free for qualified medical. California: each year's earnings (averaging ~$13,000 in later years) are taxed at the 9.3%–13.3% marginal rate. Cumulative additional California tax: roughly $20,000–$30,000 over the 20-year horizon, depending on bracket and turnover.

Common mistakes

• Holding high-turnover funds inside an HSA in California. Capital gains realizations are state-taxable annually. Buy-and-hold ETFs minimize state-level drag.
• Forgetting to track HSA basis for California. California gives a state-level basis for contributions; on withdrawal of nonqualified amounts, the federal taxable portion differs from the state taxable portion. File Schedule CA carefully.
• Assuming federal conformity for §199A or bonus depreciation. California disallows both.
• Failing to establish nonresidency cleanly before a large Roth conversion. California aggressively contests domicile changes. See our domicile-planning article.

Sources

• California Revenue & Taxation Code §17131.4, HSA nonconformity: leginfo.legislature.ca.gov §17131.4
• California Revenue & Taxation Code §17043, mental health services tax: leginfo.legislature.ca.gov §17043
• 4 U.S.C. §114, source-tax limitation on pensions: law.cornell.edu/uscode/text/4/114
• California Franchise Tax Board Publication 1005, Pension and Annuity Guidelines: ftb.ca.gov pub 1005
• California Code of Civil Procedure §704.115, retirement-plan creditor exemption: leginfo.legislature.ca.gov §704.115

California-specific drag affects every retirement projection. Explore the free educational tool.