Learn

Tax guides for investors

Number-first guides to the rules that surprise investors at filing. Every guide links the calculator that runs the same math — free, no sign-up.

Equity compensation · 9 min readThe complete guide to RSU taxes in 2026Why 22% withholding rarely covers the bill — and the W-4 fix that closes the gap.

Estimated tax · 7 min readSafe harbors, explainedThe 90% and 100%/110% targets that zero the underpayment penalty.

Estimated tax · 5 min readThe 110% safe-harbor rule, explainedLast year's AGI over $150k? Your harbor is 110% of last year's tax.

Estimated tax · 8 min readQuarterly estimated tax dates for 2026The four 2026 deadlines, what each covers, and what missing one costs.

Investing · 8 min readHow the 0/15/20% capital-gains brackets workWhere your next dollar of gains lands — with 2026 breakpoints.

Capital gains · 7 min readLong-term vs. short-term capital gainsThe one-year line: what the same sale costs held 8 months vs 14.

Capital gains · 8 min readThe 3.8% NIIT: when the investment surtax actually bitesWho pays the 3.8% surtax, on what income, above which frozen thresholds.

Equity compensation · 9 min readWhy the 22% RSU withholding falls shortThe flat 22% covers you inside the 22% bracket and leaks above it.

Original data · 4 min readThe RSU withholding gap index50 computed scenarios: where the flat 22% breaks, and by how much.

Equity compensation · 6 min readSell-to-cover, explained (and why it still leaves you short)Your broker sells enough shares for 22% — not your real rate.

Supplemental wages · 8 min readHow bonuses are taxed: the 22% withholding rule22% on the check is a placeholder, not your rate. The 37% rule above $1M.

Penalties · 7 min readThe underpayment penalty: how §6654 actually worksHow §6654 computes the charge, the 2026 rate, and three ways out.