US Tax Tools

Equity Compensation Tax Hub

Every calculator and guide for equity compensation tax — from RSU vesting and ISO AMT planning to 83(b) elections and pre-IPO double-trigger structures. Pick the calculator that matches your grant type below, or read the in-depth guides for the strategy behind the math.

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RSU (Restricted Stock Units)

Taxed as ordinary income at vest; capital gains on sale of held shares.

Stock Options (ISO & NSO)

Bargain element at exercise (ordinary for NSO, AMT preference for ISO), capital gain on sale.

ESPP (Employee Stock Purchase Plan)

§423 qualified plans: lookback, qualifying vs disqualifying disposition, no FICA.

83(b) Election & Early Exercise

30-day window to convert future ordinary income at vest into capital gain — for RSAs and early-exercised options.

QSBS (Section 1202)

Up to 100% federal exclusion on qualifying C-corp stock held 5+ years, capped at greater of $10M or 10× basis per issuer.

AMT & Credits

ISO bargain element AMT planning and the multi-year Form 8801 credit carryforward.

Supporting Calculators

Capital gains, NIIT, quarterly estimates — used downstream of equity sale events.

In-depth guides

Strategy and worked examples behind the calculators.

RSU Multi-State Allocation Explained: Workday Fraction Method

How RSU vest income is allocated across US states when you change state between grant and vest. Workday-fraction method, IRS guidance, CA + NY + 14-state grid.

2026-05-02

RSU Trailing State Tax Explained: CA + NY After You Move

When you sell RSUs after moving states, your former state may still claim the W-2 portion. Learn CA FTB Pub 1004 + NY 14-day rule + Form 540NR / IT-203 filing.

2026-05-02

83(b) Election Deadline 2026: 30 Calendar Days, No Extensions

Section 83(b) election must be postmarked within 30 days of grant — the Tax Court has rejected every late-filing excuse. Step-by-step filing guide for 2026.

2026-04-26

Double-Trigger RSUs Explained: Pre-IPO Tax, IPO Day, and the 22% Trap

Most private tech companies grant double-trigger RSUs that defer income recognition until both time vest AND a liquidity event. The structure protects employees from owing tax on illiquid stock — but creates a multi-million-dollar single-day income event at IPO with a punishing supplemental-withholding gap.

2026-04-26

ESPP Qualifying vs Disqualifying Disposition: Lesser-of Rule, FICA Exemption, and the Lookback

§423 Employee Stock Purchase Plans use a 'lesser-of' rule on qualifying dispositions that trips up most tax software defaults. Plus the FICA exemption that survives both qualifying AND disqualifying treatment, and how the 15% lookback discount produces ordinary-income recognition that exceeds the actual gain.

2026-04-26

The $100,000 ISO Limit Explained: When ISOs Auto-Convert to NSOs

IRC §422(d) caps the aggregate fair market value of stock that can become first-exercisable in any one calendar year as ISO at $100,000 per employee. Anything above is automatically reclassified as NSO regardless of grant agreement. How to detect when you trip the cap and what changes when you do.

2026-04-26

QSBS Exemption Guide: How Section 1202 Excludes Up to 100% of Founder Gain

Qualified Small Business Stock under IRC §1202 lets eligible founders and early employees exclude federal capital gains tax — up to the greater of $10 million or 10× basis per issuer — when selling C-corp stock held five years. The qualification tests, the 5-year hold, the $50M aggregate-asset cap, and which states refuse to conform.

2026-04-26

RSU 1099-B Cost Basis Correction: Form 8949 Code B Walkthrough

Brokerages routinely report $0 cost basis on Form 1099-B for RSU and ESPP sales — even though you already paid ordinary income tax on the vest-day FMV. Without a basis correction on Form 8949, you pay tax twice on the same dollars. Step-by-step on the code B adjustment.

2026-04-26

RSU Sell-to-Cover Explained: How Many Shares Disappear at Vest

Sell-to-cover withholds shares at vest to pay federal tax (typically 22% supplemental), Social Security, Medicare, and state. Why your net-share count is always less than you expected, the supplemental withholding gap, and when same-day-sale or cash withholding is the better choice.

2026-04-26

RSU Tax Guide: How Restricted Stock Units Are Taxed at Vesting and Sale

Restricted stock units are taxed twice — once as ordinary income at vest, again as capital gains at sale. A complete guide to withholding, double-taxation traps, and the tax-smart way to manage your RSU grant.

2026-04-17

Alternative Minimum Tax (AMT) Explained: Who Pays It in 2025

Understand how the Alternative Minimum Tax works, the 2025 AMT exemption amounts, income triggers, and strategies to avoid or minimize AMT liability.

2026-03-18

Last updated June 24, 2026 Tax year 2025-26

Data sources: IRS (irs.gov), Social Security Administration

This tool is general information only, not financial advice.

Reviewed by USTax Tools Editorial Desk

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