Source policy
What these links do and do not prove
- Official sources anchor the rule family behind a calculator or guide.
- They do not turn Equity Tax Lab into professional tax, legal, payroll, accounting, or investment advice.
- When official guidance is incomplete or unclear, pages should say so instead of filling the gap with personal advice.
Official sources
These links are used to verify the source family behind the page. They do not replace professional advice for personal facts.
- IRS Topic No. 427, Stock Options IRS · Checked 2026-05-20
Stock option tax treatment overview and ISO/NSO source family.
- IRS Publication 15-T (2026), Federal Income Tax Withholding Methods IRS · Checked 2026-05-20
Federal withholding method references and supplemental wage context.
- IRS Topic No. 409, Capital Gains and Losses IRS · Checked 2026-05-20
Capital gain/loss classification and holding-period context.
- IRS Publication 550, Investment Income and Expenses IRS · Checked 2026-05-20
Investment income, basis, and sale-related source family.
- IRS Publication 525, Taxable and Nontaxable Income IRS · Checked 2026-05-20
Restricted property and Section 83(b) source family.
- IRS Form 15620, Section 83(b) Election IRS · Checked 2026-05-20
Section 83(b) election form reference and deadline context.
- IRS Form 3921, Exercise of an Incentive Stock Option Under Section 422(b) IRS · Checked 2026-05-20
ISO exercise reporting context and Form 3921 records.
- IRS Instructions for Forms 3921 and 3922 IRS · Checked 2026-05-20
Information return context for ISO exercises and ESPP transfers.
- IRS Form 6251, Alternative Minimum Tax - Individuals IRS · Checked 2026-05-20
AMT form context for ISO planning and full-return AMT calculation.
- IRS 2026 Tax Inflation Adjustments IRS · Checked 2026-05-20
Tax year 2026 federal threshold update context.