Your 2026 Tax Projection: Why November Is the Month to Run It

You log into your payroll and equity portals in November and look across ten months of pay stubs, bonus slips, and company stock vestings. With only a few pay cycles left on the calendar, cumulative income numbers are largely set, yet the withholding lines on those stubs tell only part of the story. An estimated 2026 tax projection completed in November shows where total tax obligations stand while the 2026 calendar year remains open. April 15 is when you report what happened, but December 31 is when your decisions permanently close.

A tax projection compares estimated annual income against cumulative payroll withholdings to verify whether safe harbor thresholds are met.

Why November Is the Time for a 2026 Tax Projection

Many high earners review their taxes only when tax season arrives in the spring. By April, every transaction from the prior year has hardened into history. If an employer withheld too little on equity compensation or bonuses, withholdings cannot be adjusted retroactively to avoid an underpayment penalty.

Reviewing a year-end tax planning checklist in November provides the necessary runway to calculate where you stand. Evaluating total income before December leaves time to adjust withholding on remaining paychecks or plan for the fourth estimated tax payment.

Why Withholding Gaps Create April Surprises

High-earning tech professionals frequently encounter unexpected tax liabilities due to how employers withhold on supplemental wages. Federal withholding on supplemental wages, such as bonuses, severance, and RSU vesting events, is set at a flat 22%, rising to a mandatory 37% only on supplemental wages exceeding $1 million in the year.

When an executive sits in the 32%, 35%, or 37% federal tax bracket, that flat 22% rate creates an immediate withholding deficit on every vesting batch. In addition, California RSU tax rates treat vesting shares as ordinary income, where top state rates can reach 12.3%, plus a 1% surcharge on taxable income over $1 million. When withholding falls short across multiple employers, taxpayers can owe substantial balances in April. The situation compounds when navigating severance and equity vesting in the same year, where multiple supplemental payouts push income into top tiers without matching withholdings.

Wages and supplemental compensation also trigger payroll taxes: Social Security tax applies up to the 2026 wage base of $184,500, alongside Medicare tax and the 0.9% Additional Medicare Tax on wages exceeding $200,000 for single filers or $250,000 married filing jointly.

How the Federal Estimated Tax Safe Harbor Works

Under IRS rules on underpayment penalties, taxpayers who underpay their obligations throughout the year may face additions to tax. The federal tax system operates on a pay-as-you-go basis, but the tax code provides safe harbor rules to protect filers from penalties.

Under federal statutory provisions under 26 U.S. Code § 6654, there is generally no federal underpayment penalty if withholding plus timely estimated payments cover the smaller of 90% of the 2026 tax or 100% of the 2025 tax. If 2025 adjusted gross income was over $150,000 ($75,000 married filing separately), the prior-year figure is 110% instead of 100%.

Timing plays a crucial role in meeting these standards. Withholding is generally treated as paid evenly through the year, even when it happens in December. Estimated payments count on the date they are paid. That is why extra withholding late in the year can cover earlier quarters and a late estimated payment cannot. The fourth federal estimated payment for 2026 is due January 15, 2027. Furthermore, California has its own estimated payment rules. California's rules differ and a strategist checks both.

Moving Parts That Shape Your Full-Year Liability

A projection evaluates several intersecting elements that dictate your final tax position:

• Equity Vesting and Share Lots: Year-end reviews often look at holding periods for ESPP share lots to distinguish qualifying from disqualifying dispositions.
• Charitable Strategies: High earners frequently evaluate timing for charitable gifts of appreciated shares before December 31 to optimize itemized deductions.
• State Residency and Sourcing: Multi-state wage allocations or recent relocations alter how California sources equity and compensation.
• Payroll Deferral Deadlines: Employee deferrals into company 401(k) plans must be processed from 2026 paychecks before year-end.

This planning applies directly to California tech professionals, executives, and high earners earning $300,000 or more with concentrated stock, bonuses, or equity grants. It does not apply to employees whose income consists solely of steady base salary fully covered by standard payroll allowances.

Questions to Bring to a Tax Strategist

When reviewing your year-end financial numbers, consider these targeted questions:

1. Does my total 2026 withholding meet the 110% prior-year safe harbor threshold based on my 2025 tax return?
2. If my equity compensation left a withholding gap, can increasing December payroll withholding eliminate earlier quarter underpayments?
3. How do California state estimated payment rules interact with my federal withholding balance?
4. What open decisions regarding equity lots, retirement plan deferrals, or charitable timing should be finalized before December 31?

Before December 31, comprehensive year-end tax planning evaluates personal and business income, equity positions, and cumulative withholdings to build a strategy for the decisions still open.

FAQ

What is the withholding tax rate on RSUs?

Under federal rules, supplemental wages such as RSU vesting events are subject to a flat 22% withholding rate, and a mandatory 37% rate on supplemental wages exceeding $1 million in the calendar year. Because high earners often sit in higher brackets, this flat withholding can create a shortfall.

Do RSUs have FICA taxes?

Yes. RSU vest income is treated as ordinary wage income. It is subject to Social Security tax up to the 2026 wage base of $184,500, regular Medicare tax, and the 0.9% Additional Medicare Tax on wages exceeding $200,000 for single filers or $250,000 married filing jointly.

What is the tax planning process?

The tax planning process evaluates projected income from wages, equity vesting events, and capital gains against cumulative tax withholdings. Strategists analyze state and federal safe harbor thresholds to determine whether estimated payments or withholding adjustments are required before the tax year closes.

How does the federal safe harbor protect against underpayment penalties?

Taxpayers generally avoid an underpayment penalty if withholding plus timely estimated payments cover the smaller of 90% of the 2026 tax or 100% of the 2025 tax. If 2025 adjusted gross income exceeded $150,000 ($75,000 married filing separately), the prior-year benchmark is 110%.

This article is for educational purposes only and does not constitute tax, legal, or investment advice.