RSU tax rate in California: state, federal, and FICA on vest income

Searches for an RSU tax rate in California usually mean you want one percentage to plan cash for a vest — but California does not publish a separate equity rate. RSU vest FMV is taxed as ordinary wages under progressive FTB brackets, and your effective rate depends on total taxable income for the year, not the vest alone.

Federal progressive income tax and FICA apply on top of California state tax. FICA runs nationwide on vest wages with Social Security stopping at the annual wage base and Medicare applying to the full amount. California SDI and other payroll items may appear on your vest pay stub as separate lines from state income tax withholding — check the stub rather than assuming one combined state rate.

Employer supplemental withholding on RSU vests often uses flat methods under IRS Pub. 15 and California supplemental rules that can under-withhold compared with your true stacked marginal rate on salary plus vest. A Bay Area employee planning a large quarterly vest should model California marginal rate with all income, not a single bracket snippet from a rate table.

California adds a meaningful state layer that no-tax states like Texas, Washington, and Florida do not impose on vest wages for typical residents. Moving from California to a no-tax state mid-year triggers a part-year California return on pre-move connected income; vests while you were a CA resident generally stay California-connected. Remote CA residents working for out-of-state employers still typically owe California tax on vest wages as resident income.

The practical planning number is a combined estimate: California marginal state rate plus federal marginal rate plus remaining FICA and SDI on the vest FMV. Use the California RSU tax guide for mechanism detail and the California RSU tax estimator for a stacked-income estimate rather than a single flat percentage from an old source.

• ✓CA state withholding on vest pay stub.
• ✓W-2 Boxes 16–17 CA wages and tax.
• ✓Vest FMV in Box 1 and state boxes.
• ✓CA marginal rate estimate with all income.
• ✓Withholding gap for CA plus federal.
• ✓Move date if part-year resident.
• ✓FTB allocation if multi-state W-2.

• ✓CA vest pay stub state lines.
• ✓W-2 CA wage boxes.
• ✓Vest confirmation.
• ✓CA Form 540 inputs if filing resident return.
• ✓Move documentation if part-year.

• ✓Multi-state vest with CA allocation dispute.
• ✓Part-year resident CA return with large equity income.
• ✓Employer withheld wrong state on CA resident vest.
• ✓Deferred compensation or cross-border CA situation.