Accountants for RSUs: What a CPA Should Handle for a High-Income Family

By Kevin Luu, Co-Founder and Chief Learning Officer. Reviewed on 2026-09-30.

If your household earns $750,000 or more and RSUs vest every quarter, you usually need an accountant who prepares equity-compensation returns every week, not a general preparer. The right CPA or enrolled agent does three things a software package will not: corrects the cost basis your broker reports so the same income is not taxed twice, closes the gap between what was withheld at vest and what you actually owe, and handles California allocation when anyone in the family has moved. RSUs do not need an exotic tax strategy. They need someone who checks the details every year.

This page explains what to expect from an accountant for RSUs, how that role differs from the person who plans when you sell, the questions that separate the two kinds of preparer, and a worked example of what a missed basis adjustment costs at this income level.

Why RSU households outgrow a general tax preparer

RSUs themselves are simple: the value of the shares on the day they are delivered is wages, reported on your W-2, and there is no 83(b) election for them (Treas. Reg. §1.83-3(e)). The trouble is everything around the vest:

• Withholding is a flat rate, not your rate. Employers usually withhold 22% federal on supplemental wages, and 37% only on supplemental wages above $1,000,000 from that employer in the year (IRS Publication 15, 2026). For California, many employers use the 10.23% flat supplemental rate that the 2026 EDD guide sets for bonuses and stock options, though an employer may instead figure withholding on the combined regular and supplemental pay (EDD DE 44, 2026). For 2026, a married couple filing jointly pays 35% federal from $512,450 of taxable income and 37% above $768,700 (Rev. Proc. 2025-32).
• Sales generate a Form 1099-B that can be wrong. When shares are sold, the broker may report a cost basis that leaves out the income already taxed on your W-2. Unless someone corrects it on Form 8949 (Form 8949 instructions), the return taxes the vest a second time.
• Estimated payment rules get stricter at the top. Federally, paying 110% of last year’s tax generally avoids a penalty when prior-year AGI was over $150,000 (Form 1040-ES). California does not allow the prior-year safe harbor once current-year California AGI reaches $1,000,000; estimates must be based on 90% of this year’s tax (FTB).
• Moves create allocation work. California taxes nonresidents on equity compensation tied to work performed in California (FTB Publication 1100). A family that relocates to Seattle mid-grant typically still owes California tax on the part of each later vest tied to California workdays.

Each of these is routine for a preparer who sees fifty RSU returns a season. Each is easy to miss for one who sees five.

Worked example: what a missed basis adjustment costs a $1.05 million household

Assumptions (illustrative, 2026): Priya is an engineer at a Cupertino tech company with a $350,000 salary and $450,000 of RSUs vesting during the year. Her husband Sam is a hospital-employed physician earning $250,000. They file jointly with W-2 wages of $1,050,000, and assume federal taxable income of about $1,000,000 and California taxable income of about $1,020,000 before any errors. They have two children, ages 4 and 8.

In March, 1,000 shares vest at $180, so $180,000 goes on Priya’s W-2. She sells them in May at $185. Her real gain is $5,000, short term. Her broker’s 1099-B shows the $185,000 of proceeds with a basis of $0.

The fix is a single adjustment on Form 8949 that raises the basis to $180,000, using the supplemental statement most stock plan administrators publish. The NIIT line uses the 3.8% rate on net investment income above $250,000 of modified AGI for joint filers (IRS). California taxes capital gains at ordinary rates, so there is no lower state rate even on long-term lots (FTB). Our guide on how to report RSUs on your tax return walks through the form line by line.

The second issue in the same household is the withholding gap. Assume Priya’s employer uses the flat supplemental rates. On her $450,000 of vests, 22% federal withholding is $99,000. Because the vests sit on top of both salaries, they fill federal taxable income from about $550,000 to $1,000,000: $218,700 at 35% and $231,300 at 37%, or $162,126 of federal income tax. That leaves about $63,126 of income tax unpaid by default. California is close to even at this income: 10.23% withheld is $46,035 against about $46,105 owed across the 9.3%, 10.3% and 11.3% brackets plus the 1% tax on taxable income over $1,000,000 (FTB 2025 schedules, the latest published). Because their California AGI is above $1,000,000, they also cannot rely on last year’s tax to avoid a California penalty. A good accountant spots that in a September projection, not in April.

What to ask before hiring an accountant for RSUs

Credentials tell you who is allowed to represent you before the IRS. CPAs, enrolled agents and attorneys all can, and the IRS keeps a public directory of preparers with credentials. Experience with equity compensation is a separate question. These six answers usually sort it out:

1. How many of your returns include W-2 equity compensation? You want a practice where RSUs, ESPP and options are normal, not occasional.
2. Do you reconcile every 1099-B against the stock plan’s supplemental statement? The answer should be yes, every lot, every year.
3. Do you run a mid-year projection? A projection in the third quarter, with real vest values and both spouses’ pay, is when the withholding gap can still be fixed with a new W-4 or an estimated payment.
4. How do you handle California AGI over $1,000,000? They should mention the current-year estimate rule and the 1% Behavioral Health Services Tax without prompting.
5. Have you prepared California nonresident allocations or Washington capital gains returns? Washington has no wage income tax for 2026 (WA DOR), but it taxes long-term capital gains at 7% above the standard deduction ($278,000 for 2025, the latest published) and 9.9% on taxable gains over $1,000,000 (WA DOR capital gains tax). It has also enacted a 9.9% income tax on AGI over $1,000,000 starting in 2028.
6. Will you work directly with our financial planner? The accountant reports what happened. Someone has to decide what happens next, and the two need to talk before December, not after.

Accountant versus planner: who plans RSU sales across several years

A common search is whether someone can plan RSU sales and withholding across multiple years to reduce taxes. Part of the answer is a hard limit: the vest itself cannot be moved. The shares are wages when they are delivered, whether you sell or hold. What can be planned across years is everything after the vest:

• Which lots to sell, and when. Selling right after vest typically produces little gain. Older lots with large gains can be spread across tax years, or matched against losses elsewhere in the portfolio.
• Which lots to give. Donating shares held more than a year, directly or through a donor-advised fund, can generally produce a deduction at fair market value (subject to AGI limits) without tax on the gain (IRS Publication 526). This works with old, appreciated lots, not with shares that just vested.
• How much income to shelter. Each spouse can defer $24,500 into a 401(k) or 403(b) for 2026 (IRS Notice 2025-67). For Priya and Sam, $49,000 of deferrals removes income taxed at 37% federal and 11.3% California, plus the 1% California tax on the $20,000 that sat above $1,000,000 of taxable income: roughly $23,867 of income tax for the year.
• How concentrated to stay. Holding vested shares is the same decision as taking a cash bonus and buying your employer’s stock. That is an investment question, covered under investment risk management, more than a tax one.

In most families, the accountant prepares the return and the projection, and a fee-only planner owns the multi-year sale and giving schedule. What matters is that one person is responsible for coordinating them. For a family of delegators, that coordination is usually the thing missing. Our tax management work at Age Five Family Office™ starts there.

Common mistakes with RSU tax preparation

• Importing a 1099-B into tax software and accepting the basis it shows.
• Assuming the 22% withheld at vest settled the tax. At 35% or 37% federal, it rarely does. Our comparison of withhold to cover and sell to cover explains where the withheld shares go.
• Holding shares a full year to get “capital gains treatment” on the vest. Only growth after vest can be a capital gain.
• Meeting the accountant once a year, in March, when every number is already final.
• Leaving California allocation until the year after a move, when the records are harder to rebuild.

What to write down for your kids

The record that helps your children most is not the return. It is a short note on how you handled equity pay: what you did on vest day, how you set aside taxes, how much of one company you were willing to hold, and who you trusted to check the work. Kept in the family’s FamilyKnowledge® Library, that note shows them how a decision was made, not just what it cost.

Frequently asked questions

Do I need a CPA if my only complication is RSUs?

Not always. A single vesting schedule with sell-at-vest and no state moves can be handled carefully in software, provided you correct every 1099-B basis. Once you hold shares across years, have two earners above $500,000, cross $1,000,000 of California AGI, or have moved states, an accountant who regularly prepares equity-compensation returns usually earns the fee.

Can an accountant reduce the tax on my RSU vest?

Not on the vest itself. The share value on delivery is wages at your marginal rate. An accountant can check that you are not taxed twice on a sale, time estimated payments to help avoid penalties, and that retirement deferrals and gifts of appreciated shares are used. The larger savings usually come from decisions made before year end.

Is an enrolled agent as good as a CPA for RSU returns?

Both are credentialed to prepare returns and represent you before the IRS. For RSUs, experience matters more than the letters: ask how many equity-compensation returns they prepare, whether they reconcile supplemental statements, and whether they run mid-year projections. A specialist enrolled agent is often a better fit than a generalist CPA.

Next step

Pull last year’s Form 1099-B and your stock plan’s supplemental statement and check one sale: does the reported basis match the vest value on your W-2? If it does not, ask your preparer whether it was adjusted. If you would like a second set of eyes on the return and the year ahead, that review is part of our Tax & Wealth Assessment.

This is general education, not individual tax advice. The right move depends on your family’s full picture, including both incomes, grant schedules and state residency.

Written by

Kevin Luu

Co-Founder and Chief Learning Officer, Bright Advisers

Kevin has advised high-income W-2 tech and biotech families since 2015, and leads the education-first Age Five Family Office from Brea, California.

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