ESPP Basis Mistakes That Change Your Tax Bill

An employee stock purchase plan (ESPP) lets you buy company stock at a discount, often through payroll. Tax timing depends on whether the sale is a qualifying disposition or disqualifying disposition, and where the bargain element appears (W-2 vs. only on the sale). Broker-reported basis on 1099-B is often wrong because it may omit ordinary income already taxed on your W-2.

TL;DR

Qualifying vs. disqualifying dispositions change how much ordinary income you recognize and when.
Discount may be taxed as compensation (often on W-2) and affects stock basis.
1099-B may understate basis; use Form 8949 adjustments with the correct code.
Keep plan statements for every purchase lot.

Qualifying disposition (high level)

If you hold shares long enough after purchase (and after grant, depending on plan type), you may get preferential treatment for part of the gain—rules are strict; read IRS Publication 525 and your plan document.

Disqualifying disposition

More common in practice for quick sales: you may recognize ordinary income for the bargain element in addition to capital gain/loss on the sale.

Document proof callout: Your ESPP purchase confirmation shows grant date, purchase date, FMV, and discount.

Why brokers mis-report basis

Brokers may not know how much ordinary income your employer put on your W-2 for the same shares. Result: Basis too low → capital gain too high → overpaid tax if you do not adjust.

Worked example (illustrative)

Purchase at $85 when FMV was $100 (15% discount).
Ordinary income piece may be $15/share taxed as wages (timing depends on disposition).
Sale at $110: capital gain should not tax the $15 again if basis was stepped up correctly.

FAQ

Do I attach explanations to the return?
Software often handles codes; keep PDFs for audit.

What if I have multiple lots?
FIFO vs. specific identification—broker rules vary.

How to act on this today

Verify your W-2 + 1099-B + ESPP statements in one trace, or register to compute Schedule D with document-backed basis.

Educational content only—not individualized tax advice.