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 ($8,750) 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 California also does not recognize the federal §402(d) 10-year averaging election for lump-sum distributions (repealed federally for most filers but preserved for those born before 1936); residents who relied on it before moving to California should expect different treatment.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 2026 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 $8,750 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.