California RSU Source Rules: Vesting Income for Movers and Nonresidents

California starts from a plain idea. A restricted stock unit is pay for services, so the state taxes the part of that pay earned while working inside California. The California RSU vesting income source rules turn that idea into a ratio. Count the business days between the grant date and the vesting date, then apply the share of those days worked in California to the value of the shares delivered at vest. The measuring period closes at vest for a restricted stock unit, which is a different window from the one used for a nonstatutory stock option, where the count runs all the way to exercise. Residency on the vesting date matters, though not the way most people expect. A California resident on that date is taxed by California on the entire amount, because a resident owes tax on income from every source. A nonresident on that date is taxed only on the California slice the ratio produces. Someone who changed residency during the year files as a part year resident and reports both pieces on one return. The Franchise Tax Board publishes its guidance for nonresidents and for equity pay at ftb.ca.gov, and the allocation itself is carried on the California nonresident return through Schedule CA, a form with no federal counterpart.

Here is the arithmetic. An engineer receives 4,000 units with a four year vest and works 1,000 business days between grant and the final tranche, 600 of them at a California office. That is 60 percent. When the shares deliver at 25 dollars, the vest is worth 100,000 dollars and California claims 60,000 dollars of it. At a 9.3 percent marginal rate the state tax on that slice comes to 5,580 dollars, and the upper California brackets run past 12 percent before the additional 1 percent tax on income above 1,000,000 dollars. California is a high tax state. It gives no preferential rate to long term capital gain, so the eventual sale of those same shares is taxed by the state at ordinary rates even though the federal return applies the lower rate through Schedule D. California also runs its own alternative minimum tax, which can surface in a heavy vesting year and surprise a household that has never seen it before. The vest carries a payroll tax bill that ignores the state ratio entirely, since Social Security and Medicare apply to the full delivered value.

The common mistake is treating the vesting date as the only date that counts. A taxpayer who moved to Nevada in March and vested in June often assumes the whole vest is now beyond California. It is not, because the ratio looks backward across the entire grant to vest window. The opposite error costs just as much. A person who moved into California late in the vesting period sometimes reports the full amount to the state and overpays by thousands. Federal reporting is not in dispute either way, since the whole vest is wages in box 1 of the Form W-2 and flows to Form 1040 no matter which state collects. Employers almost never revisit a prior year allocation, so the correction happens on the taxpayer’s own return or it does not happen at all. Our individual tax return work handles the federal and multi state filings as one job, and the planning around a vesting calendar sits inside tax strategy consulting. Anyone holding a grant that began in California should build the workday record now, because reconstructing three years of travel from memory is the part that falls apart under review. Keeping that file along the lines the IRS describes in its recordkeeping guidance costs almost nothing today.

Payroll and sourcing answer to different masters. A payroll system withholds state tax for the state where the employee is working right now, using the address and work location loaded in the employer record. The sourcing formula looks at the whole grant to vest history instead. Those two views agree only by accident. An employee who transferred from San Jose to Seattle in year three usually sees state withholding stop the moment the work location changed, even though most of the vest was earned in California. Some large employers do run a workday allocation and withhold to more than one state, which is better but rarely exact, because the allocation is often built from the payroll address history rather than an actual travel record. Remote work widens the gap further. An employee whose payroll record says Denver but who spends one week a month in a Sunnyvale office is generating California workdays that no system is counting. California applies a flat supplemental withholding rate above 10 percent to bonus and equity wages it treats as sourced to the state, so the number can also swing the other way and overshoot. The state boxes on the Form W-2 tell you what the employer decided. They do not tell you what the state is owed.

Run the numbers on the same 100,000 dollar vest. California source income is 60,000 dollars and the state tax is roughly 5,580 dollars. If the employer withheld nothing to California because the employee now sits in Washington, that entire amount is due with a nonresident return, plus interest and possibly an underpayment penalty. If the employer instead withheld on the full 100,000 dollars, about 9,300 dollars went to Sacramento and roughly 3,720 dollars of it comes back only after a nonresident return is filed and processed. The same mismatch appears for a taxpayer who never lived in California at all but travelled there for a project during the vesting window. Neither outcome is a filing error by the employer. Both are the predictable result of a payroll system doing the job it was built to do. The federal side has its own gap in the same year, since the flat 22 percent supplemental rate on the vest rarely covers a taxpayer in a higher bracket, a point Publication 505 covers in detail.

The repair is a mid year review rather than an April discovery. Model the year with the IRS Tax Withholding Estimator, cover the federal shortfall through a revised Form W-4 or a payment with Form 1040-ES, and make a separate California estimated payment through the Franchise Tax Board at ftb.ca.gov for the state slice. California expects those payments on its own quarterly rhythm, with installment percentages that differ from the federal pattern. Federal penalty exposure is computed on Form 2210 and California runs a parallel calculation. The mistake we see most often is assuming that a large withholding number on the pay stub means the year is covered, when the stub was never measuring the right base. A short worksheet listing each tranche against its vest date and running workday split takes twenty minutes and settles the question for the whole year. Employees who also run a side business should fold that income into the same projection, which is where clean bookkeeping earns its keep, and the filing itself runs through individual tax returns. Check the first vest of the year against the formula in the same month it happens, and the remaining tranches can still be corrected while there is payroll left to adjust.

Yes, for the portion earned inside the state. Under the California RSU vesting income source rules the move changes the taxpayer’s residency, not the history of where the work was performed. Income already earned by California workdays keeps its California character even though the shares deliver years later and the taxpayer now lives in Texas or Florida. This is the single point that generates the most disagreement, and it is also the point the Franchise Tax Board is most consistent about in its published guidance at ftb.ca.gov. The residency change does help going forward. Workdays after the move belong to the new state, so a longer post move stretch inside the vesting window shrinks the California ratio for every tranche that vests afterward. It also means each tranche has its own percentage. A grant with four annual vests can easily produce four different California ratios, falling year by year as the out of state workdays accumulate. Deferred compensation of other kinds can behave differently, so a cash bonus plan and an equity grant should never be allocated with the same worksheet without checking each arrangement on its own terms.

Take a manager who was granted 8,000 units in California and moved to Austin exactly two years into a four year vest. Roughly half the workdays in the full window were California days. On a final tranche worth 200,000 dollars, about 100,000 dollars is California source and the rest is not. The first tranche that vested while the manager still lived in California was taxed by the state in full as resident income. Later tranches are reported on a nonresident return with only the sourced share. A tranche that vests during the year of the move itself can carry a resident piece and a nonresident piece on the same return. The mistake that costs the most is silence. Some taxpayers stop filing in California entirely after a move, and the state later matches the employer wage report to a missing return. California has a long look back window for a taxpayer who never filed, and the notice usually arrives with interest attached. The payroll department is generally out of the picture by then, which leaves the taxpayer carrying the burden of proof. Federal reporting continues unchanged on Form 1040 using the same Form W-2 figures.

Residency itself has to be documented rather than asserted. California looks at where the home is, where the family lives, where vehicles are registered, where professional licenses are held, and how the days actually break down across the year. A taxpayer who keeps a house in Palo Alto and returns for two weeks a month is a difficult case, whatever the driver license says. Selling the shares right after a vest does not change the sourcing of the wage element, though it does start a separate holding period for any later gain. Anyone who filed on the assumption that a move ended all California exposure can correct earlier years, using Form 1040-X federally when the federal numbers also move and the state amended return for California itself. We build these multi year positions inside tax strategy consulting and then carry them into the returns through individual tax returns, keeping the support organized the way the IRS describes in its recordkeeping guidance. Anyone planning a move within the next year should count the remaining vesting workdays before choosing a departure date, because the calendar is one of the few levers still available.

Relief comes through a credit, not by leaving the income off a return. The state where the taxpayer lives at vest taxes the whole amount as resident income. California taxes its sourced share as nonresident income. The resident state then allows a credit for the tax paid to California on the doubly taxed portion, capped at the resident state tax on that same income. California residents claim the mirror image credit on Schedule S when another state taxes income they also report at home, and a handful of states use a reverse arrangement where the credit is claimed on the other state’s return instead of the California one. Some states compute the credit from a percentage of income rather than from tax actually paid, which changes the result when the two rate schedules differ sharply. The order of filing matters in practice, because the credit needs the other return finished first. None of this reduces the federal bill, which is computed once on Form 1040 from the wage figures on the Form W-2 without regard to any state allocation.

The arithmetic decides how much the credit is worth. Suppose 100,000 dollars of vest income is sourced to California and the taxpayer now lives in a state with a 5 percent flat rate. California collects about 9,300 dollars. The home state computes 5,000 dollars on the same income and allows a credit of 5,000 dollars, so the home state collects nothing on that slice. Total state cost is 9,300 dollars rather than 14,300 dollars. The credit protects against paying twice, and it never refunds the difference between a high rate state and a low rate one. A taxpayer who moves to a state with no income tax has no credit to claim at all, and the California tax is simply a cost of the years worked there. Timing adds friction, because California processes a nonresident refund on its own schedule and the home state credit sometimes needs an amended filing once the final California number is known. Selling the shares afterward opens a separate calculation, reported federally on Form 8949 with the basis rules explained in Publication 550.

Two California specifics deserve attention. The state does not follow every federal rule, so a return that copies federal numbers will be wrong in places. It decouples from parts of the federal depreciation regime and gives no deduction for qualified business income, which leaves a household with any business activity looking at two different profit figures. It also applies ordinary rates to capital gains rather than the federal preferential rate. Anyone who owns a California limited liability company carries an 800 dollar minimum franchise tax plus a fee based on gross receipts, and that bill lands in the same year as a large vest. The mistake we correct most often here is a return that excludes the California income from the resident state return instead of reporting it and claiming the credit. That approach draws a notice from the home state and forfeits the credit. High earners should also watch the 3.8 percent net investment income tax on Form 8960, since wages sit outside that tax while a large vest lifts the income measure that pulls investment income into it. We coordinate the two state returns inside tax strategy consulting and file them together through individual tax returns. Model both states before the next tranche vests, because the credit math often changes which month a planned move should happen.

The formula is only as good as the day count behind it. Keep the grant agreement and every vest confirmation, since those two documents fix the beginning and the end of each measuring period. Keep a workday calendar for each year of the vesting window, supported by something objective such as travel bookings, office badge records, or a calendar export. Badge data and airline records age out of most systems quickly, so pull them during the vesting years rather than when a letter arrives. Keep pay stubs showing which state received withholding in each period, along with every Form W-2 including the state boxes at the bottom. Keep prior returns for both states. A short memo written at the time of a move, describing the reason and the date, carries real weight years later. A taxpayer who can produce these files answers a Franchise Tax Board letter in one exchange, and a taxpayer who cannot usually accepts the state’s version by default. The Franchise Tax Board explains what it expects to see at ftb.ca.gov, and the federal habits described in the IRS recordkeeping guidance work well for the state file too.

The dollars justify the filing cabinet. On a grant that produces 200,000 dollars of vest income with half sourced to California, the state tax runs near 9,300 dollars. A workday record that moves the ratio from 50 percent to 40 percent saves roughly 1,860 dollars on that tranche alone, and the same correction repeats on every remaining vest. Where an earlier year was filed on a wrong assumption, an amended return can recover the difference within the open period, four years for California in most cases. When the federal figures shift as well, that correction runs on Form 1040-X. Interest accrues from the original due date on any state balance, which is why a voluntary correction beats waiting for the state to find the gap. An IRS account transcript is the fastest way to confirm what employers actually reported before an amendment is prepared. If a notice arrives first, read it against Understanding Your IRS Notice or Letter and answer with documents rather than argument.

A note on our role, because equity questions tend to drift. The Reed Corporation is a CPA and tax firm and not a registered investment adviser. We do not manage portfolios and we do not tell anyone whether to hold shares after a vest or sell them the same morning. We handle the tax side, we build the workday allocation, and we work with the client’s own licensed advisors so the tax plan and the financial plan point in one direction. Grants issued before a move and grants issued after it should be tracked separately, since only the older ones carry a California history. A vest that lands in the same year as a home sale or a large bonus needs the whole picture modeled at once rather than one item at a time. Households with a side consulting entity should also remember that a California limited liability company owes the 800 dollar minimum franchise tax and a gross receipts fee regardless of the equity income, which is one more reason the monthly numbers matter and where our bookkeeping work fits. Clients facing a first large vest can request a consultation before the shares deliver rather than after. Build the workday file in the first year of every grant and the California RSU vesting income source rules become an arithmetic exercise rather than an argument, whichever state the household ends up calling home. Our individual tax return team keeps that file current from one year to the next.